ENGINE CONTROL MODULE (ECM)
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The ECM is located behind the secondary bulkhead panel in the centerline of the vehicle. The ECM is attached to a bracket with four screws which is secured to the bulkhead panel. The ECM receives inputs from various sensors and outputs reference voltages and signal information to other sensors for engine control.
The ECM receives and processes information from the following input sources:
Outputs:
The ECM is connected to the vehicle harnesses via two connectors. The ECM contains data processors and memory microchips. The output signals to the actuators and sensors are in the form of ground paths provided by driver circuits within the ECM. The ECM driver circuits produce heat during normal operation and dissipate this heat via the ribbed casing.
The ECM performs self-diagnostic routines and stores fault codes in its memory. These fault codes and diagnostics can be accessed using the approved diagnostic system. If the ECM is to be replaced, the new ECM is supplied 'blank' and must be configured to the vehicle using an approved diagnostic system. A 'flash' electrically erasable programmable read only memory allows the ECM to be externally configured, using an approved diagnostic system, with market specific or new tune information up to 14 times. If a fifteenth update is required the ECM must be replaced. The current engine tune data can be accessed and read using an approved diagnostic system.
When a new ECM is equipped, it must be synchronized to the Central Junction Box (CJB) and the Electric Steering Column Lock (ESCL) control module for immobilization purposes using an approved diagnostic system.
ECM's cannot be 'swapped' between vehicles.
The ECM is connected to the engine sensors which allow it to monitor the engine operating conditions. The ECM processes these signals and determines the actions necessary to maintain optimum engine performance in terms of driveability, fuel efficiency and exhaust emissions. The memory of the ECM is programmed with instructions for how to control the engine, this known as the strategy. The memory also contains data in the form of maps which the ECM uses as a basis for fueling and emission control. By comparing the information from the sensors to the data in the maps, the ECM is able to calculate the various output requirements. The ECM contains an adaptive strategy which updates the system when components vary due to production tolerances or ageing.
Some sensors receive a regulated voltage supplied by the ECM. This avoids incorrect signals caused by voltage drop during cranking.
The ECM receives a vehicle speed signal on the High Speed Controller Area Network (HS-CAN) powertrain systems bus from the Anti-lock Brake System (ABS) control module. Vehicle speed is an important input to the ECM strategies. The ABS control module derives the speed signal from the ABS wheel speed sensors. The frequency of this signal changes according to road speed. The ECM uses this signal to determine the following:
Crankshaft Position (CKP) Sensor
Electric Throttle
Fuel Rail Pressure
Control Valve (PCV)
Rear end Sheet Metal
Repairs Rear
Bumper Retaining
Rail (G1770947) / Removal
and Installation
Fluid Level and Condition
Checks