ECM CAN Messages
- Make
- Land Rover
- Model
- Freelander System Description and Operation (UK)
- Section
- Description and operation › ECM CAN Messages
Engine management system - siemens (all except NAS)ECM CAN Messages
Controller Area Network (CAN) Bus: The ECM is connected to the Anti-lock Braking System (ABS) modulator, EAT ECU and the instrument pack by the CAN bus. The CAN bus is a serial communications data bus, consisting of a pair of wires twisted together, that allows the high speed exchange of digital messages between control units.
ECM CAN Messages
| Inputs | Outputs |
|---|---|
| A/C request. Instrument pack requests A/C on when A/ C switch and blowers are on. Used for condenser clutch and cooling fan control. | Actual engine torque. Current engine torque including any torque reduction. Expressed as a percentage of maximum engine torque. Used by EAT ECU for gear change scheduling. |
| Cooling request. Request by EAT ECU for additional cooling of the transmission fluid. The ECM switches on, or increases the speed of, the cooling fans. | Engine coolant temperature. Used by EAT ECU for diagnostic functions and to detect when the engine has completed a 'warm up' cycle. Used by instrument pack to drive engine temperature gauge. |
| Current/Target gear. EAT ECU informs the ECM what gear is currently engaged or, if a gear change is in progress, the gear to which the gearbox is changing. Used for engine load change prediction. | Engine friction. Informs the EAT ECU of the current frictional torque losses within the engine. Expressed as a percentage of maximum engine torque. Used for gear change scheduling. |
| Fuel level. Instrument pack informs the ECM of the level of fuel in the tank. Used for misfire monitoring. | Engine management fault. Indicates that a non emissions related fault has been detected. |
| Gear selector lever position. EAT ECU informs the ECM of the gear selector lever position selected by the driver. Used for idle speed control. | Engine speed. Used by EAT ECU to calculate gearbox oil pressure to assist with gear change scheduling. Also used by instrument pack to drive tachometer. |
| Gear change in progress. EAT ECU informs the ECM when a gear change is in progress. Used at idle speed to compensate for engine load changes during the gear change. | Engine speed error. Informs the EAT ECU if there is a fault with the engine speed calculation. If necessary, the EAT ECU adjusts gearbox operation to prevent possibility of mechanical damage. |
| Gearbox fault. EAT ECU informs the ECM there is a transmission fault that requires the MIL to be illuminated. | Engine torque error. Informs the ABS modulator and EAT ECU if there is an engine torque measurement error. |
| Rough road signal. From ABS modulator for use in misfire monitoring. | Fuel consumption. Used by instrument pack to calculate service intervals. Derived from fuel injection dwell times. Broadcast every 10 milli-seconds as cumulative volume used. Measured in micro-litres and begins counting from zero again when value reaches 65535 micro-litres. |
| Torque reduction request. ABS modulator requests the ECM to reduce engine torque to assist with traction control. Amount of torque reduction required expressed as a percentage of maximum engine torque. | Ignition switch status. Used to initiate the EAT ECU power-down routine at ignition off. |
| Torque reduction request. EAT ECU requests the ECM to reduce engine torque for a gear change (equivalent to lifting off the throttle in manual gearbox models). Amount of torque reduction required expressed as a percentage of maximum engine torque. | Indexed engine torque. Theoretical maximum engine torque for current engine operating conditions. Expressed as a percentage of maximum engine torque. Used by ABS modulator and EAT ECU for torque reduction request calculations and gear change scheduling. |
| Torque increase request. ABS modulator requests a minor increase in engine torque when brakes are off and ABS function is triggered by engine braking. Amount of torque reduction required expressed as a percentage of maximum engine torque. | MIL status. Indicates to instrument pack if MIL should be on or off. Used by EAT ECU to discontinue emissions related OBD. |
| Vehicle speed. Current vehicle speed as calculated by ABS modulator using mean wheel speeds. | Throttle angle. Used by EAT ECU for gear change scheduling (kickdown) and ABS modulator for hill descent control. |
| Brake intervention activity status. ABS modulator informs ECM when ABS, ETC or HDC functions use brake intervention. ECM suspends misfire detection during brake intervention. |
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