Engine Controls - Tests W/codes: Other Mitsubishi Galant VIII

Hard Failures

Hard failures cause MIL to come on and remain on until failure is repaired. If MIL comes on and remains on (MIL may flash) during vehicle operation, cause of failure may be determined by using DTCs. See DIAGNOSTIC TROUBLE CODES (DTCS) . If a sensor fails, PCM will use a substitute value in its calculations to continue engine operation. In this condition (limp-in mode), vehicle is functional, but loss of good driveability may result.

Intermittent Failures

Intermittent failures may cause MIL to flicker or come on and go out after intermittent DTC goes away. However, corresponding DTC will be retained in PCM memory. If related DTC does not reoccur within a certain time frame, related DTC will be erased from PCM memory. Intermittent failures may be caused by a sensor, connector or wiring problems. See INTERMITTENTS in TESTS W/O CODES article.

SERVICE PRECAUTIONS

Before proceeding with diagnosis, following precautions must be observed

1. Ensure vehicle has a fully charged battery and functional charging system.
2. Visually inspect connectors and circuit wiring being worked on.
3. DO NOT disconnect battery or PCM. This will erase any DTCs stored in PCM.
4. DO NOT cause short circuits when performing electrical tests. This will set additional DTCs, making diagnosis of original problem more difficult.
5. DO NOT use a test light in place of a voltmeter.
6. When checking for spark, ensure coil wire is NOT more than 1/4" from chassis ground. If coil wire is more than 1/4" from chassis ground, damage to vehicle electronics and/or PCM may result.
7. DO NOT prolong testing of fuel injectors. Engine may hydrostatically (liquid) lock.
8. When a vehicle has multiple DTCs, always repair lowest number DTC first.

CLEARING DTCS

To clear DTCs using a scan tool, refer to owners manual supplied with scan tool. If scan tool is not available, DTCs may also be cleared by disconnecting negative battery cable or PCM for at least 15 seconds, allowing PCM to clear DTCs. Reconnect negative battery cable and check for DTCs to confirm repair.

INTERMITTENT DTCS

This procedure applies if you have been sent here from diagnostic tests and have just attempted to simulate the condition that initially set the DTC. The following additional checks may assist in identifying a possible intermittent problem

1. Visually inspect related wiring harness connectors for broken, bent, pushed out or corroded terminals.
2. Visually inspect related wiring harness for chafed, pierced or partially broken wires.
3. Check all pertinent technical service bulletins.

No Communication With All Systems

1. Check voltage between ground and DLC terminal No. 16. If battery voltage does not exist, check connectors and wiring harness between DLC and power supply. If battery voltage exists, go to next step.
2. Check continuity between ground and DLC terminal No. 4, and between ground and terminal No. 5. If continuity exists, replace scan tool. If continuity does not exist, check wiring harness between ground and DLC.

No Communication With PCM

1. Check connectors and wiring harness between PCM and DLC and between PCM and power supply. If wiring and connectors are okay, check MFI relay. See RELAYS in «SYSTEM/COMPONENT TESTS»(ref-19368) article. If MFI relay is okay, go to next step.
2. Remove MFI relay. Check voltage between ground and MFI relay connector terminal No. 3. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring harness between MFI relay and battery.
3. Turn ignition on. Check voltage between ground and MFI relay connector terminal No. 4. If battery voltage exists, go to next step. If battery voltage does not exist, check connectors and wiring harness between ignition switch and MFI relay. If connectors and wiring are okay, check ignition switch.
4. Disconnect PCM connector. Turn ignition on. Check voltage between ground and PCM connector terminal No. 82. If battery voltage exists, go to next step. If battery voltage does not exist, check junction connector between MFI relay connector and PCM and wiring harness between ignition switch connector and PCM. If wiring and connectors are okay, check ignition switch.
5. Check voltage between ground and terminal No. 38. If battery voltage exists, go to next step. If battery voltahge does not exist, check connectors and wiring harness between MFI relay and PCM.
6. Turn ignition on. Check voltage between ground and PCM connector terminals No. 12 and 25. If battery voltage exists, go to next step. If battery voltage does not exist, check connectors and wiring harness between MFI relay and PCM.
7. Check continuity between ground and PCM connector terminals No. 13 and 26. If continuity exists, go to next step. If continuity does not exist, check wiring harness between ground and PCM.
8. Check voltage between ground and PCM connector terminal No. 60. If battery voltage exists, check PCM connector. If PCM connector is okay, replace PCM. If battery voltage does not exist, check wiring harness between PCM and battery.

MALFUNCTION INDICATOR LIGHT (MIL)

Note. For terminal identification, see TERMINAL IDENTIFICATION in SELF-DIAGNOSTICS section. For circuit and wire color identification, see WIRING DIAGRAMS article.

MIL Does Not Come On

1. Using scan tool in MUT II mode, read SERVICE DATA No. 16 (PCM power supply voltage). If battery voltage exists, go to step 8). If battery voltage does not exist, go to next step.
2. Disconnect PCM connector. Turn ignition on. Check voltage between ground and PCM connector terminal No. 82. If battery voltage exists, go to next step. If battery voltage does not exist, check junction connector between MFI relay connector and PCM and wiring harness between ignition switch connector and PCM. If wiring and connectors are okay, check ignition switch.
3. Check voltage between ground and PCM harness connector terminal No. 38. If battery voltage exists, go to next step. If battery voltage does not exist, check connectors and wiring harness between MFI relay and PCM.
4. Turn ignition on. Check voltage between ground and PCM connector terminals No. 12 and 25. If battery voltage exists, go to next step. If battery voltage does not exist, check connectors and wiring harness between MFI relay and PCM.
5. Check continuity between ground and PCM connector terminals No. 13 and 26. If continuity exists, go to next step. If continuity does not exist, check wiring harness between ground and PCM.
6. Check voltage between ground and PCM connector terminal No. 60. If battery voltage exists, check PCM connector. If PCM connector is okay, replace PCM. If battery voltage does not exist, check wiring harness between PCM and battery.
7. Turn ignition off. Disconnect PCM connector. Connect jumper wire between ground and PCM connector terminal No. 36. Turn ignition on. If MIL comes on, check PCM connector. If PCM connector is okay, replace PCM. If MIL does not come on, go to next step.
8. Check for open bulb. If bulb is okay, disconnect combination meter connector D02. Turn ignition on. Check voltage between ground and combination meter connector D02 terminal No. 24. If battery voltage exists, check junction connectors and wiring harness between combination meter connector and PCM. If battery voltage does not exist, check power supply circuit to MIL.

Malfunction Indicator Light (MIL) Stays On

1. Using scan tool, check for stored DTCs. See ENTERING ON-BOARD DIAGNOSTICS under SELF-DIAGNOSTIC SYSTEM section. If no DTCs are displayed, go to next step. If DTCs are displayed, record all DTCs and go to «DIAGNOSTIC TROUBLE CODE (DTC) INDEX»(ref-19252-S31511729702002090600000) table. After dientifying DTCs, go to appropriate test(s) under CIRCUIT TESTS.
2. Disconnect PCM connector. Disconnect combination meter connector D02. Check continuity between ground and combination meter connector C04 terminal No. 51 or D02 terminal No. 28. If continuity exists, check wiring harness between combination meter connector and PCM. If continuity does not exist, replace PCM.

SUMMARY

If no hard DTCs (or only pass DTCs) are present, driveability symptoms exist, or intermittent DTCs exist, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.