Chart 4 Service Engine Soon MIL Inoperative

Chart 4:

Service Engine Soon Circuit:

CIRCUIT DESCRIPTION
The "Service Engine Soon" Malfunction Indicator Lamp (MIL) is controlled by the Powertrain Control Module (PCM) through CKT 419. When the MIL lights, it indicates that the PCM has detected a problem that affects vehicle emissions and may cause powertrain damage or severely impact driveability.

SERVICE ENGINE SOON MIL ON
1. Malfunction: When certain PCM codes are current. Refer to, Diagnostic Trouble Code Description under Vehicle On-Board Diagnostics for those codes that turn "ON" the "Service Engine Soon" MIL. Diagnostic Trouble Code Descriptions

2. Diagnostic Mode: After the indicator and segment check, the telltale should remain "ON."

SERVICE ENGINE SOON MIL OFF
1. Key "ON," engine not running.

2. Engine running: No PCM codes current. The telltale can be off with PCM codes stored. Refer to Diagnostic Trouble Code Description under Vehicle On-Board Diagnostics for those codes that do NOT turn "ON" the "Service Engine Soon" MIL. Diagnostic Trouble Code Descriptions

NOTES ON FAULT TREE
1. Checking if "Service Engine Soon" MIL circuitry is OK and the PCM is unable to control output.

2. Checking CKT 419 for an open.

3. Checking for an open in CKT 39 or inside the Instrument Panel Cluster (IPC).