Pcm Output Diagnosis (2.2L & 2.4L): Notes
NOTE:
The following procedure DOES NOT apply to 2.2L Saturn.
- Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
- Turn ignition on, with engine off. Connect scan tool to Data Link connector (DLC). If a No. 1 is displayed below any of the number output drivers, go to next step. If a No. 1 is not displayed below any of the number output drivers, go to step 4.
- Disconnect electrical connector from component related to malfunctioning circuit. If a No. 1 is still displayed below corresponding output driver, go to step 6. If a No. 1 is not displayed below any of the number output drivers, go to step 9.
- Using scan tool, command output being checked while watching corresponding position for that circuit. If that circuits position does not change to a No. 1, go to next step. If that circuits position changes to a No. 1, go to step 7.
- If component or function does not operate when commanded, go to step 9. If component or function operates when commanded, go to step 11.
- Turn ignition off. Check for open, short to voltage or short to ground in any corresponding circuit indicating a No. 1 below output driver. Repair component or component circuit as necessary and go to step 11. If circuits are okay, go to step 10.
- Disconnect electrical connector from component related to malfunctioning circuit. Using scan tool, command output being checked while watching corresponding position for that circuit. If a No. 1 is still displayed below corresponding output driver, go to next step. If a No. 1 is not displayed below any of the number output drivers, go to step 9.
- Turn ignition off. Check for open, short to voltage or short to ground in any corresponding circuit indicating a No. 1 below output driver. Repair component or component circuit as necessary and go to step 11. If circuits are okay, go to step 10.
- Diagnose and repair any component that malfunctioned when commanded with scan tool. After repairs, go to step 11.
- Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
- Start engine and operate vehicle under condition under which original symptom was noted. If system does not operate properly, go to step 2. If system operates properly, see DIAGNOSTIC AIDS .