Engine Control Module (ECM)
The Engine Control Module (ECM) is located on the RH side A post below the face panel inside the vehicle. See Fig 1. It has a cast aluminum case and is mounted on a bracket. The ECM has 5 independent connectors totalling 134 pins.
The ECM is available in 4 variants:
- NAS (North Americian Version)
- NAS Low Emission Vehicles
- UK/Europe/Japan/Australia
- ROW/Gulf
The ECM uses a FLASH electronic erasable programmable read only memory (EEPROM). This enables the ECM to be externally configured, to ensure that the ECM can be updated with any new information, this also allows the ECM to be configured with market specific data. Textbook/T4 must be used to configure replacement ECM's. The ECM can be reprogrammed, using TestBook/T4, with new engine tunes up to 16 times to meet changing specifications and legislation. The current engine tune data can be accessed and read using TestBook/T4.
The ECM memorizes the positions of the crankshaft and the camshaft when the engine has stopped via the CKP and CMP sensors. This allows immediate sequential fuel injection and ignition timing during cranking. This information is lost if battery voltage is too low (i.e. flat battery). So the facility will be disabled for the first engine start.