Circuit Description
The engine control module (ECM) is the control center of the fuel injection system. It constantly looks at the information from various sensors, and controls the system that affect vehicle performance. The ECM also performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the malfunction indicator lamp (MIL) (Check Engine), and store a diagnostic trouble code (DTC) or DTCs which identify the problem areas to aid the technician in making repairs. The ECM detects communication link failure with immobilizer control unit.
Conditions for Running the DTC
| • | No immobilizer message identification for ECM release time window (1.5 or 2.0 seconds). |
| • | Ignition switch is turned to ON. |
| • | Vehicle speed sensor (VSS) is less than 512 km/h. |
Action Taken When the DTC Sets
| • | The MIL will not illuminate. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records buffers. |
| • | A history DTC is stored. |
Conditions for Clearing the MIL/DTC
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | DTC(s) can be cleared by using the scan tool. |
| • | Disconnecting the ECM battery feed for more than 10 seconds. |
Step | Action | Yes | No |
|---|---|---|---|
1 | Perform an On-Board Diagnostic (EOBD) System Check. Was the check performed? | Go to Step 2 | |
2 |
Did you complete the replacement? | Go to Step 3 | -- |
3 |
Does the scan tool indicate that this diagnostic has run and passed? | Go to Step 4 | Go to Step 2 |
4 | Are any DTCs displayed that have not been diagnosed? | Go to Applicable DTC table | System OK |
