Megasquirt MS3 Competition Installation

The Megasquirt MS3 competition is our top-of-the-line unit at the moment. It is very versatile and allows for many different configurations. Several features have been improved, which we believe were necessary, such as:

• The inputs for crankshaft position sensors, main camshaft sensor, and secondary camshaft sensor.
• The ignition outputs, which allow most digital coils to function, even the famous VAG coils installed in TFSi and TSI engines.
• It allows for the installation of ignition controllers for high-power coils inside, eliminating the need for expensive external modules.
• It directly includes inputs and outputs in the connectors that were inaccessible on the V3 board.
• Pre-installed inputs and outputs are provided in the connector for future expansions.
• It is possible to install internal circuits for inductive ABS sensors.

In this manual, you will find the schematics for installation. If you have any doubts about the use of this unit or the correct configuration for your project, please consult us, and we will advise you.

General recommendations for installation: do not skip this point; it is very important.

Before starting the ECU connection, there are some general recommendations on how to perform the electrical installation. Ignition and electronic injection systems can cause many problems due to electromagnetic interference if certain considerations are not taken into account. All of them are equally important. Once a problem occurs, it is very difficult to diagnose. Please follow these instructions. Symptoms include voltage spikes from the battery, noise in sensor signals, unstable RPM signals, and loss of connection between the ECU and the PC. All of this causes frustration for the user. Read carefully and try to do a good job with your installation. This will make you happy, and you won’t go crazy looking for electronic ghosts.

• Do not connect the grounds to the chassis or bodywork. The grounds must be connected to the engine block, preferably at the same point where the battery is grounded to the engine. The battery usually has two cables connected to the negative terminal: one goes to the chassis, and the other goes to the engine block. It is at this point on the engine block where the ECU grounds should be connected. If you have previously modified the battery’s location, you should run a cable from the battery to the engine block, just like it was connected originally. If the distance is long, try using a thicker cable than the original.
• Clean this point thoroughly, removing paint, grease, or dirt, before connecting the grounds.
• Do not combine all the pins marked as ground into a single cable and run it to the block. For each pin marked as ground on the ECU connector, run a separate cable to the chosen ground point. At this point, you can join all the cables into a terminal and screw it to the block.
• Separate the ECU wiring from the rest of the vehicle wiring (alternator cables, starter motor, etc.). These cables draw significant power and can create interference in the injection and ignition system, which is very difficult to diagnose. It is even advisable to separate the wiring from the ECU that connects to the coils and their grounds from the rest of the wiring. As you will see, we have tried to separate these connections in all our units when possible. The ignition coils draw significant power, between 6 and 8 Amperes, compared to just a few milliamperes drawn by the ECU itself. Additionally, the pulses that activate and deactivate the coils, along with their high intensity, are a source of problems on their own. Try to run this wiring and its grounds through a different path from the sensor wiring and the ECU power supply.
• Avoid routing the ECU wiring close to any engine component that generates electromagnetism, has a high energy consumption, or works with high voltages (starter motor, alternator, ignition coils, spark plug cables, etc.).
• Check the condition of the alternator, starter motor, ignition coils, spark plug cables, etc. Many of the problems we have found in installations are caused by malfunctioning of these components.
• Do not use spark plug cables like those used in carburetor systems. These do not have any protection against interference. Always install spark plug cables designed for fuel injection systems and check their condition.
• Wiring diameter and distribution: If you bought automotive wiring from our store, you will see that it has wires of two different diameters. These are designed for the consumption of each component.
• If you are using a USB to RS232 adapter, install a DB9 to DB9 cable or connect three cables (preferably shielded) in the connector and use the adapter directly on the PC. If you connect the adapter directly to the ECU, you may lose communication with the PC at any time. The quality of the adapter is important. Many adapters work intermittently, so try to buy one of acceptable quality.
• The wideband connection is usually made through 4 cables in most cases, but today it is typically 3 cables:

- Power +12V: It is recommended that the sensor does not operate until the engine is running. If this happens, water condensation in the exhaust or unburned fuel from startup could enter the sensor and destroy it. For this reason, we recommend connecting the power supply of the sensor to the fuel pump relay. This will only activate when the engine is running.

- Electronic ground: This is the ground for the internal electronic circuit. It should go to the same point as the ECU ground, with a separate cable running to the block.

- Heater ground: Today’s systems have combined the electrical ground and heater ground, so they will only have one ground. If there is one, it is better to run this ground through a separate cable to the engine block.

- AFR signal: This should be connected to the ECU to read the air-fuel ratio.

1- General Diagram and Connection.

The following image shows the distribution of the unit connectors and the function of each pin. The connectors are labeled with the number of each pin on the side where the cable is inserted. Ensure the correct position before starting:

Next, we show the diagram for a correct battery installation, ignition switch, relay distribution, and ECU fuse. This is the recommended way to provide power and ground. The ground points should be connected to the engine block, as explained earlier.

The diagram shows the connectors that have ground, power, or activate any relay. This is how you should perform the installation, and it has been simplified to make it clear that it is very important to connect the relays, power, and ground in this manner.

As explained earlier, the ECU grounds and the battery negative should be connected to the engine block, all at the same point but with each one running a separate cable, as follows:

• 20-pin connector: one cable from pin 4 to the engine block, one cable from pin 5 to the engine block, one cable from pin 6 to the engine block.
• 24-pin connector: one cable from pin 10 to the engine block, one cable from pin 11 to the engine block, one cable from pin 12 to the engine block, one cable from pin 16 to the engine block.
• 18-pin connector: (only for 5, 6, and 8-cylinder engines), one cable from pin 5 to the engine block, one cable from pin 6 to the engine block.
• Battery: a thick cable from the battery negative to the engine block. It is also recommended to connect the battery negative to the chassis or frame with another thick cable.

It is emphasized again: from each pin of each ECU connector, run a separate cable to the engine block, and from the battery negative, run a thick cable to the engine block, all at the same point on the engine block. Any other way of connecting the grounds is incorrect and can cause problems that are difficult to resolve. 

Relay and fuel pump grounds can be connected to the chassis or frame, but try to keep the ground as close as possible to the component in question. If you need to pass the ground through the body, it is advisable to clean the area where the bolt connects to remove paint and grease. This will provide a solid connection.

Always use a separate wire for each component’s ground connection. Try to avoid combining all grounds into a single wire, which is an incorrect practice.

Next, we show a diagram of how to connect the components. You must follow these instructions to ensure a correct and stable installation:

We hope this installation guide helps you make a successful and interference-free installation. If you follow these instructions closely, you will avoid future headaches and your car’s ECU will function optimally.

Optical or Hall sensors have 3 wires: power, signal, and ground. Our wiring includes 3 wires and a protective shield.

• The wire connected to pin 9 is connected to the sensor signal.
• The wire connected to pin 10 is free, without connection.
• You will find a wire not connected; this wire is intended to provide power to the optical or Hall sensor. Take this wire to the output (pin 87) of the relay that powers the ECU.

If you do not need the input for a camshaft phase sensor, you can connect an ABS sensor or a speed sensor so that the unit shows the vehicle's speed. Once speed is indicated, you can make other configurations, such as gear indicator, turbo pressure control by speed, and many other features. It can also be used as a switched output to ground, requiring a Pull-Up resistor to 5V.

11-Table Switch IN. Its function is to activate or deactivate two different maps. For other uses, more information can be found in point 6.2.

12-Air Temperature Sensor. Temperature sensors used in injection systems have two terminals: one terminal is connected to pin 12, and the other terminal is connected to pin 7 (sensor return). These sensors are not polarized.

13-Oxygen sensor or wide-band input signal. Read the device instructions for connection; the ECU only needs a signal between 0V and 5V. The probe should not be turned on before starting the engine, or it will suffer premature failure. The controller power is connected to a relay that supplies power only when the engine is running. The ground of the controller should go to the engine block, same as the rest of the ECU grounds.

14-Throttle Position Sensor (TPS) signal. The TPS is polarized and has three terminals, which are:

• +5V power, to pin 8 of the ECU connector.
• Ground, to pin 7 of the ECU connector (sensor return).
• Signal, to pin 14 of the ECU connector.

To identify each terminal of the TPS, you need to perform some tests with a tester. By measuring resistance, you should look for two terminals that do not vary their resistance when opening or closing the throttle. These will be +5V and ground. The remaining terminal is the signal terminal.

Once the signal terminal is identified, you must determine which of the two terminals that do not vary the resistance when opening or closing the throttle is +5V and which is ground. To do this, measure the resistance between one of them and the signal terminal. If the resistance is high with the throttle closed and decreases as it opens, it is the +5V terminal. If it behaves the opposite, it is the ground terminal.

15-Engine Temperature Sensor. Temperature sensors used in injection systems have two terminals: one terminal is connected to pin 15, and the other terminal is connected to pin 7 (sensor return). These sensors are not polarized.

16-PT4. More information can be found in points 6.3 and 6.4.

17-18-Crankshaft sensor input. Its original function is for the camshaft phase sensor input. It supports inductive sensors and optical or Hall sensors. Inductive sensors do not require voltage to operate, while optical or Hall sensors need voltage in both the power and signal for proper functioning. The default setup is for inductive sensors, but the ECU is designed to send a voltage to the signal if optical or Hall sensors are used. We need you to specify which type of sensor you will use so we can configure the unit for proper operation.

The connection of the different types of sensors is shown in the following image:

Inductive sensors have two signal wires. If there is a third wire, it is a shield to protect the signal from interference. Our wiring includes 3 wires and a protective shield:

• The shield is connected to a black wire that exits the harness and must be connected to ground, for example, to one of the holes that support the ECU. Make sure it's a good ground.
• The wires connected to pins 17 and 18 are the ones to connect to the sensor.
• You will find another wire not connected in case it is necessary for an optical or Hall sensor. In this case, it is not needed; leave it unconnected.

Optical or Hall sensors have 3 wires: power, signal, and ground. Our wiring includes 3 wires and a protective shield.

• The wire connected to pin 18 is connected to the sensor signal.
• The wire connected to pin 17 is free, without connection.
• You will find a wire not connected; this wire is intended to provide power to the optical or Hall sensor. Take this wire to the output (pin 87) of the relay that powers the ECU.

19-20-Camshaft sensor input. It supports inductive sensors and optical or Hall sensors. Inductive sensors do not require voltage to operate, while optical or Hall sensors need voltage in both the power and signal for proper functioning. The default setup is for inductive sensors, but the ECU is designed to send a voltage to the signal if optical or Hall sensors are used. We need you to specify which type of sensor you will use so we can configure the unit for proper operation.

The connection of the different types of sensors is shown in the following image:

Inductive sensors have two signal wires. If there is a third wire, it is a shield to protect the signal from interference. Our wiring includes 3 wires and a protective shield:

• The shield is connected to a black wire that exits the harness and must be connected to ground, for example, to one of the holes that support the ECU. Make sure it's a good ground.
• The wires connected to pins 19 and 20 are the ones to connect to the sensor.
• You will find another wire not connected in case it is necessary for an optical or Hall sensor. In this case, it is not needed; leave it unconnected.

Optical or Hall sensors have 3 wires: power, signal, and ground. Our wiring includes 3 wires and a protective shield.

• The wire connected to pin 19 is connected to the sensor signal.
• The wire connected to pin 20 is free, without connection.
• You will find a wire not connected; this wire is intended to provide power to the optical or Hall sensor. Take this wire to the output (pin 87) of the relay that powers the ECU.

If you do not need the input for a camshaft phase sensor, you can connect an ABS sensor or a speed sensor so that the unit shows the vehicle's speed. Once speed is indicated, you can make other configurations, such as gear indicator, turbo pressure control by speed, and many other features. It can also be used as a switched output to ground, requiring a Pull-Up resistor to 5V.

3-Injection.

The ECU has 8 injection outputs, each designed for a maximum of 5 Amperes. Free injection outputs (not used for controlling an injector) can also be used for other features, such as activating warning LED lights, relays, solenoids, or valves, etc. This makes the unit very flexible and will surely allow you to carry out several functions with just one unit. For example, you can use a second output to feed your water or methanol injector and control the power of the system based on boost pressure. For more advanced configurations, feel free to consult more details.

To activate an injector or other devices, connect the circuit to pins 1 to 8, depending on your needs. There is a logic in this case for ECU output operation. This works by switching the ground side of the device.

Each output also has an individual fuse protection, and the units already include these fuses so they don't have to be added separately. A simple fuse 5A is sufficient.

4-Ignition.

The ECU has 8 ignition outputs installed that send a 5V pulse for logic coils (with built-in amplifier). For high-current coils connected directly to the ECU, it is necessary to install ignition drivers inside the unit. These are optional and only required for this type of coil; if needed, they must be included when purchasing the unit. If you have questions about configuring the ignition outputs, please consult us.

Unused ignition outputs (not used to control ignition coils) can be used in various ways:

• Programmable outputs (something happens when a setpoint is reached).
• 2D Maps.
• 3D Maps.
• 3D Maps with closed loop.

This gives the ECU a lot of flexibility and allows you to implement your own adjustment strategies, activate warning LEDs, relays, solenoids, or valves, etc. Keep in mind that with the basic configuration, the unit sends 5V and very low current; you will not be able to use these outputs for components that require medium-high current or ground switching to operate. These outputs are designed for logic coils or sending signals to an external ignition module, although they can be used to activate warning lights, for example for failure, over-temperature, over-pressure, shift alert, etc. If you need these outputs to handle medium-high current or switch to ground, for example, solenoids, valves, etc., ignition drivers should be installed; remember they are optional. The following image shows some examples of how to connect components to these outputs depending on your configuration. If you have questions about how the unit is configured, you can test with a voltmeter to see if the output delivers 5V using the test mode.

The way to connect ignition coils will depend on the tone wheel and position sensors of the engine. To perform wasted spark ignition, a crankshaft tone wheel with missing teeth is needed, for example, 36-1, 60-2. For sequential ignition, a tone wheel and engine phase sensor on the camshaft or distributor are required. Some factory systems have their own designs, such as Mitsubishi, Subaru, Nissan, Toyota, etc., many of which are configured and can be used. Depending on the system, the ignition can operate in sequential or wasted spark mode; consult us if you have questions.

The following diagrams show the most common engines and ignition systems and the recommended connection for ignition coils between the unit and its power supply from the relay or relays. With a large number of coils, it is advisable to install a second relay to avoid overloads. Fuse installation is very important, ideally one per coil.

The diagrams shown are for coils without a built-in amplifier module, which usually have 2 connection poles: a positive (through a fuse) and a negative going to the unit. Logic coils or those with a built-in amplifier usually have 3 or 4 connection poles: a positive (through a fuse), one or two grounds to the engine block, and a signal going to the unit. In this case, it is only necessary to connect the coil signal to the unit as shown in the diagrams.

4.1-Distributor Ignition.

4.2-Wasted Spark Ignition in 4-Cylinder Engines. Firing Order 1-3-4-2:

The coils are individually connected to the unit according to the firing order.

• Coil for cylinders 1 and 4 to pin 24, SPARK A. 24-pin connector.
• Coil for cylinders 2 and 3 to pin 22, SPARK B. 24-pin connector.

4.3-Sequential Ignition in 4-Cylinder Engines. Firing Order 1-3-4-2:

The coils are individually connected to the unit according to the firing order.

• Coil for cylinder 1 to pin 24, SPARK A. 24-pin connector.
• Coil for cylinder 3 to pin 22, SPARK B. 24-pin connector.
• Coil for cylinder 4 to pin 20, SPARK C. 24-pin connector.
• Coil for cylinder 2 to pin 18, SPARK D. 24-pin connector.

4.4 - Sequential Ignition for 5-Cylinder Engines. Firing Order 1-2-4-5-3.

Coils are individually connected to the unit according to the firing order.

• Coil for cylinder 1 to pin 24, SPARK A. 24-pin connector.
• Coil for cylinder 2 to pin 22, SPARK B. 24-pin connector.
• Coil for cylinder 4 to pin 20, SPARK C. 24-pin connector.
• Coil for cylinder 5 to pin 18, SPARK D. 24-pin connector.
• Coil for cylinder 3 to pin 16, SPARK E. 18-pin connector.

4.5 - Wasted Spark Ignition for 6-Cylinder Engines. Firing Order 1-5-3-6-2-4.

Coils are individually connected to the unit according to the firing order.

• Coil for cylinders 1 and 6 to pin 24, SPARK A. 24-pin connector.
• Coil for cylinders 5 and 2 to pin 22, SPARK B. 24-pin connector.
• Coil for cylinders 3 and 4 to pin 20, SPARK C. 24-pin connector.

4.6 - Sequential Ignition for 6-Cylinder Engines. Firing Order 1-5-3-6-2-4.

Coils are individually connected to the unit according to the firing order.

• Coil for cylinder 1 to pin 24, SPARK A. 24-pin connector.
• Coil for cylinder 5 to pin 22, SPARK B. 24-pin connector.
• Coil for cylinder 3 to pin 20, SPARK C. 24-pin connector.
• Coil for cylinder 6 to pin 18, SPARK D. 24-pin connector.
• Coil for cylinder 2 to pin 16, SPARK E. 18-pin connector.
• Coil for cylinder 4 to pin 14, SPARK F. 18-pin connector.

4.7 - Wasted Spark Ignition for 8-Cylinder Engines. Firing Order 1-5-4-8-6-3-7-2.

Coils are individually connected to the unit according to the firing order.

• Coil for cylinders 1 and 6 to pin 24, SPARK A. 24-pin connector.
• Coil for cylinders 5 and 3 to pin 22, SPARK B. 24-pin connector.
• Coil for cylinders 4 and 7 to pin 20, SPARK C. 24-pin connector.
• Coil for cylinders 8 and 2 to pin 18, SPARK D. 24-pin connector.

4.8 - Sequential Ignition for 8-Cylinder Engines. Firing Order 1-5-4-8-6-3-7-2.

Coils are individually connected to the unit according to the firing order.

• Coil for cylinder 1 to pin 24, SPARK A. 24-pin connector.
• Coil for cylinder 5 to pin 22, SPARK B. 24-pin connector.
• Coil for cylinder 4 to pin 20, SPARK C. 24-pin connector.
• Coil for cylinder 8 to pin 18, SPARK D. 24-pin connector.
• Coil for cylinder 6 to pin 16, SPARK E. 18-pin connector.
• Coil for cylinder 3 to pin 14, SPARK F. 18-pin connector.
• Coil for cylinder 7 to pin 12, SPARK G. 18-pin connector.
• Coil for cylinder 2 to pin 10, SPARK H. 18-pin connector.

5 - Outputs

The unit has various outputs, some are dedicated to specific functions, while others are user-programmable. Below is a list of the current outputs, their primary function, operation, and maximum allowable current for each.

Some of these outputs are specific for their function, while others can be used in various ways:

• TACHO, designed to provide the signal to a tachometer. The current it can supply is small. This output can also be used to light a warning light or power small loads. Never use this output as a ground switch.
• FP (Fuel Pump), exclusively designed to activate the fuel pump relay.
• PK7 - PM2 - PK3 - PK1: These outputs are installed for future expansions or to connect external modules. If you connect any of these outputs directly, it will cause irreversible damage to the processor. DO NOT USE THESE OUTPUTS; LEAVE THEM UNCONNECTED. In the future, there may be modules available for connection to these outputs, in which case, follow the connection instructions provided.
• IAC1 - IAC2, designed for idle control valves with stepper motors. The connection for an IAC is shown below:

An IAC has two coils; other types exist, but these are the most common. To identify which two pins belong to the same coil, measure the resistance. If the resistance between two pins is 30 to 50 ohms, you are measuring the two poles of one coil. Connect one of them to IAC1A and the other to IAC1B. Measure between the remaining two pins of the IAC; the resistance should match the previous measurement. If so, connect one pin to IAC2A and the other pin to IAC2B. Test the IAC in test mode; if it works correctly, great. Otherwise, two things could happen:

1. The stepper motor does not work at all. In this case, one of the coil windings has incorrect polarity. To fix this, swap the cables around either of the coil windings to see if this helps (i.e., swap the blue wires). If that does not help, reconnect the cables as they were and try swapping the green cables on the other winding.
2. The stepper motor works in reverse, meaning it retracts when it should extend and vice versa. Swap the cables as follows:

Coil 1, pin IAC1A connect to coil 2, pin IAC2A.

Coil 1, pin IAC2B connect to coil 2, PIN IAC2B.

Coil 2, PIN IAC2A connect to coil 1, PIN IAC2A.

Coil 2, pin IAC2B connect to coil 1, PIN IAC2B.

If you are testing the IAC outside the throttle body, be careful not to accidentally eject the IAC plunger. If this happens, simply reinsert it into the casing, applying gentle pressure as you screw it back down (it usually screws in clockwise, like a bolt).

If you do not need these outputs to control an IAC, you can use them for other functions. Keep in mind that the IAC operates in pairs: IAC1A sends +12V when activated, while IAC1B switches to ground. The same applies to IAC2A and IAC2B. You have two connection options: connect the positive of the component to IAC1A and the negative to ground, or connect the positive of the component to a fused +12V and the negative to IAC1B. The same applies to IAC2A and IAC2B.

• IDLE - FIDLE are designed for idle valves through PWM (Pulse Width Modulation) and are ground switching inputs. Idle valves can be 2 or 3-wire, where one wire is +12V and the other wire(s) are signals. The connection method for these valves is as follows:

• The IDLE, FIDLE outputs, and other ground-switching outputs can be used in their original function or for other purposes, such as activating warning LEDs, relays, solenoids, or valves, among others. This makes the unit highly versatile and will likely enable you to carry out many of your ideas. They can be used in the following ways:

Programmable outputs (triggered upon reaching a set condition).

2D maps.

3D maps.

Closed-loop 3D maps.

Examples of how to connect them in their original or alternative functions, such as warning lights, valves, solenoids, or relays, are shown below:

6-Inputs.

In addition to sensor inputs, there are other inputs for specific functions or user-configurable options. These inputs can be used for their designated functions or, if not needed, for other functions as required. The following table shows these inputs, their functions, input type, and supported voltage. Further explanations on their usage follow. Some of these inputs can be used as outputs, but they do not have a Mosfet or transistor installed, making their current very low. We do not recommend using them as outputs unless you understand the risks, as it may cause irreversible damage to the processor.

NOTE: Never use JS10 as an output; it has a dedicated circuit for the engine position sensor input. Using it as an output will cause irreversible damage to the ECU.

6.1-ADC (Analog-to-Digital Converters).

The inputs JS4, JS5, SPARE ADC, EGO 2, and EXT MAP are of the ADC type, converting an analog signal into a digital signal, but they can also be used as ground-switching switches. If a second MAP sensor has been chosen for constant barometric correction, EXT MAP will be internally connected to this sensor and cannot be used externally. These inputs only accept 5V signals. Below are some examples:

• Sensors. They allow converting a sensor's voltage into a measurement, such as temperature, pressure, distance, etc. Most sensors will need a resistor connected to 5V.
• Potentiometers. They allow selecting a percentage of mixtures between different maps. For example, between two turbo pressure maps, between two ignition maps, between two fuel maps, etc. They also allow controlling the sensitivity of a map, such as a very soft traction control or nearly no traction control to a very aggressive traction control.
• Switches. They enable or disable a feature. For example, launch control, traction control, dual maps, etc...
• Accelerometers. They indicate the vehicle's acceleration on up to 3 axes.

The connection of sensors, potentiometers, switches, or pushbuttons is done as shown below:

6.2-Ground-Switching Inputs.

The inputs LAUNCH IN, DATALOG IN, TABLE SWITCH IN, PE1, and JS7 are ground-switching inputs, they have an internal Pull-Up to +12V. These inputs can be used in the following ways:

• Switches. Allows activating or deactivating a feature. For example, launch control, traction control, dual maps, etc.... Its installation is identical to the one shown in the previous image.
• Pulse detection. For example, from external modules such as a knock sensor, speed sensors, or wheel sensors (explained in section 6.5), etc...

6.3-Dedicated Inputs.

Some inputs are created for a specific feature, but if not needed, they can be used for other functions.

• FLEX. Designed for a Flex Fuel sensor, this sensor measures the percentage of ethanol in the fuel. Typically, this fuel is mixed with gasoline in a certain percentage. For example, E85 means 85% ethanol and 15% gasoline, but these amounts can vary from one gas station to another or if the previous tank was 100% gasoline and not fully emptied. The sensor will measure and send a signal to the ECU with the exact proportion of ethanol and gasoline. Based on this proportion, the fuel, ignition, and turbo pressure maps can be adjusted. If this feature is not needed, the input can be used by switching to ground or as a pulse input for other functions. It accepts 5V signals, never 12V.
• NITROUS IN. Designed to receive the signal from a nitrous system. These systems usually send a +12V signal when activated to change the maps in the ECU. Therefore, this pin expects +12V for activation, not a ground switch. If this feature is not needed, the input can be used as a pulse input or switched to +12V. Remember, it needs +12V for activation, not a ground switch. It only accepts +12V signals.
• CAM IN (CAM 2 IN +). Designed for a second camshaft position sensor, it works for inductive sensors, optical sensors, or Hall sensors. If not used as a second cam sensor input, it can be used for a speed or ABS sensor, see section 6.5. Finally, it can also be used as a pulse input or ground switch (a Pull-Up resistor is needed). It accepts 5V and 12V signals.
• JS10. (CAM 1 IN +). Designed for a camshaft position sensor, the circuit works for inductive sensors, optical sensors, or Hall sensors. If not used as a cam sensor input, it can be used for a speed or ABS sensor, see section 6.5. Finally, it can also be used as a pulse input or ground switch (a Pull-Up resistor is required). It accepts 5V and 12V signals.
• PT4. Direct input to the processor, designed for crankshaft signals with high-frequency optical or Hall sensors, will not work with inductive sensors. It can be used for pulse input or ground switch. It only accepts 5V signals.

6.4-IN-OUT Inputs.

The PT4 and JS11 inputs can be used as ground switch inputs or low current outputs.

NOTE: Never use JS10 as an output, it has a dedicated circuit for engine position sensor input, using it as an output will cause irreversible damage to the ECU. 

6.5-Connection of the vehicle's speed or ABS sensors to indicate speed or traction control.

There are several types of sensors in the vehicle's ABS and speed systems: Hall sensors, inductive sensors, and magnetoresistive sensors. For traction control, at least one signal from a front wheel and one from a rear wheel is required, ideally from all four wheels. To know the vehicle's speed, the signal from one wheel or a speed sensor installed in the gearbox or differential will be enough, as many vehicles have this sensor. It is important to configure the number of teeth on the installed toothed wheels, the differential gear ratio, and the wheel diameter for correct operation.

Identifying the type of sensor used by the vehicle and how to connect it to the unit requires testing and research. The way to ensure proper sensor operation is to check how it is connected at the original source before disassembling, measure voltages on the terminals, and check the signal sent to the unit with an oscilloscope. A very brief explanation of the types of sensors and their identification is as follows:

• Hall sensors usually have 3 wires: power, ground, and signal, although many ABS systems only have 2 wires: power and signal. The toothed wheel may be a disc with holes or a gear. These sensors send a square wave signal, so they can be connected directly to the unit without the need for an additional circuit.
• Inductive sensors have 2 wires and may include an anti-parasitic shield. They typically use toothed wheels but can also have discs with holes, in which case there is usually an iron base behind the holes that makes it toothed. The signal from these sensors is alternating, and its voltage varies with the wheel's speed, so a circuit is needed to adapt the signal to a square wave that the unit can accept. This circuit is installed inside the unit; its purchase and installation are optional. If needed, you should select it during purchase.
• Magnetoresistive sensors can be identified by the toothed wheel they use, which has no holes or teeth and uses a smooth disc or wheel, making it the easiest sensor to identify. These sensors require an external circuit to function, which is currently not available.

The connection of a speed signal from the vehicle can be made in the following ways:

Hall sensors are mostly ground switch sensors, and their connection is identical to that shown for crankshaft or camshaft Hall sensors, but with the signal connected to the pin indicated below. Depending on the voltage that can be applied to the signal, the connection can be made in the following ways:

• Signal +12V: the inputs NITROUS IN, JS7, PE1, LAUNCH IN, DATALOG IN, TABLE SWITCH IN, have an internal Pull Up to +12V, so no external resistor is needed. Keep in mind that these inputs are for low frequency, wheels with few teeth.
• Signal +5V: the inputs PT4, JS11, FLEX, are perfect for +5V signals and high frequency. You will need to install a 1K Pull Up resistor.
• The inputs CAM 1 IN and CAM 2 IN accept +5V or +12V and are high frequency, wheels with many teeth. You will need to install a 5.6K Pull Up resistor (only for Hall sensors). Remember, we need to know what type of sensor will be used on these inputs for proper installation.

Inductive sensors can only be connected to (JS10) CAM 1 IN or (PT2) CAM 2 IN, as long as they are not used for camshaft signal input. The connection method is identical to that shown for crankshaft or camshaft inductive sensors. These sensors are normally found in the wheels and are part of the ABS system.

The following image is an example of the connection for 4 ABS Hall or inductive sensors. For this, an internal circuit is needed, which we are working on and hope to have available soon: