Circuit Description
The engine control module (ECM) is the control center of the fuel injection system. If constantly looks at the information from various sensors, and controls the systems 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), and store a 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 Setting the DTC
| • | No immobilizer message identification for the ECM release time window, 1.5 or 2.0 seconds. |
| • | The ignition switch is turned to ON. |
| • | The vehicle speed sensor (VSS) is less than 512 km/h (318 mph). |
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will 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. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect 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 |
Is the repair complete? | Go to Step 3 | -- |
3 |
Does the scan tool indicate that his diagnostic has run and passed? | Go to Step 4 | Go to Step 2 |
4 | Are any DTCs displayed that have not been diagnosed? | System OK |
