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 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) (Check Engine), and store diagnostic trouble code (DTC) or DTCs which identify the problem areas to aid the technician in making repairs. The ECM received incorrect message identification.
Conditions for Setting the DTC
| • | Wrong immobilizer message received. |
| • | Ignition switch is turned to ON. |
| • | Immobilizer option selected. |
| • | ECM release time window expired. |
| • | 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. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnecting the ECM battery feed for more than 10 seconds. |
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check-Engine Controls? | 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 |
