PCM Power And Ground Circuit Troubleshooting

Engine

PCM Power and Ground Circuit Troubleshooting

PCM Power and Ground Circuit Troubleshooting

1. Engine starting check:

Engine starting check
-1. Try to start the engine.

Does the engine start and idle smoothly?
-YES- The engine starts. Go to the F-CAN circuit troubleshooting Component Tests and General Diagnostics.
-NO- The engine dose not start. Go to step 2.

2. Determine possible failure area (+B_IG_MAIN wire shorted, others):

Determine possible failure area (+B_IG_MAIN wire shorted, others):
-1. Turn the ignition switch to LOCK (0).

-2. Check the following fuse.





Is the fuse OK?
-YES- Repair open in the +B_IG_MAIN wire between the No. A2-1 (50 A) fuse and the ignition switch. If the wire is OK, go to step 3.
-NO- Repair a short in the +B_IG_MAIN wire between the No. A2-1 IG MAIN (50 A) fuse and the under-hood fuse/relay box. Also replace the No. A2-1 IG MAIN (50 A) fuse.

3. Fuse check:

Fuse check
-1. Check the following fuse.





Is the fuse OK?
-YES- Go to step 8.
-NO- Go to step 4.

4. Determine possible failure area (+B_IGP line, others):

Determine possible failure area (+B_IGP line, others)
-1. Remove the blown No. A21 (15 A) fuse from the under-hood fuse/relay box.

-2. Remove PGM-FI main relay 1 (A) from the under-dash fuse/relay box.





-3. Check for continuity between test points 1 and 2.














Is there continuity?
-YES- Go to step 5.
-NO- Go to step 6.

5. Shorted wire check (+B_IGP line):

Shorted wire check (+B_IGP line)
-1. Disconnect the following connector.





-2. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- Repair a short the +B_IGP wire between the No. A21 (15A) fuse and under-dash fuse/relay box. Also replace the No. A21 (15A) fuse.
-NO- The +B_IGP wire is OK. Replace the under-hood fuse/relay box. Also replace the No. A21 (15 A) fuse.

6. Part(s) internal circuit check:

Part(s) internal circuit check
-1. Disconnect each of the parts or connectors following, one at a time, and check for continuity between test points 1 and 2.
* PGM-FI main relay 2
* PCM connector A (49P)
* Each injector 2P connector
* Camshaft position (CMP) sensor 3P connector
* Crankshaft position (CKP) sensor 3P connector
* Electronic throttle control system (ETCS) control relay









Does continuity go away when one of the above components is disconnected?
-YES- Replace the part that made the short to body ground go away when it was disconnected. If the part is the PCM, update the PCM PCM Update if it does not have the latest software, or substitute a known-good PCM Service and Repair, then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM Service and Repair. Also replace the No. A21 (15 A) fuse.
-NO- Parts are OK. Go to step 7.

7. Shorted wire check (FI_MAIN_RLY_OUT line):

Shorted wire check (FI_MAIN_RLY_OUT line)
-1. Disconnect following parts:





-2. Check for continuity between test points 1 and 2.









Does continuity go away when one of the above components is disconnected?
-YES- Repair a short in the FI_MAIN_RLY_OUT wire between PGM-FI main relay 1 and each part. Also replace the No. A21 (15 A) fuse.
-NO- The FI_MAIN_RLY_OUT wire is OK. Replace PGM-FI main relay 1. Also replace the No. A21 (15 A) fuse.

8. Fuse check 2:

Fuse check 2
-1. Check the following fuse.





Is the fuse OK?
-YES- Go to step 13.
-NO- Go to step 9.

9. Relay test:

Relay test
-1. Remove the blown No. B4 (15 A) fuse from the under-hood fuse/relay box.

-2. Remove PGM-FI main relay 2 (A) from the relay holder B (built into the under-hood fuse/relay box).





-3. Test PGM-FI main relay 2 Testing and Inspection.

Is the relay OK?
-YES- PGM-FI main relay 2 is OK. Go to step 10.
-NO- Replace PGM-FI main relay 2. Also replace the No. B4 (15 A) fuse.

10. Determine possible failure area (IG1_FUEL_PUMP line, others):

Determine possible failure area (IG1_FUEL_PUMP line, others)
-1. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- Go to step 11.
-NO- Go to step 12.

11. Shorted wire check (IG1, IG1_FUEL_PUMP lines):

Shorted wire check (IG1, IG1_FUEL_PUMP lines)
-1. Jump the SCS line with the HDS.

-2. Disconnect the following connector.





-3. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- Repair a short in the IG1/IG1_FUEL_PUMP wire between the No. B4 (15 A) fuse and the PCM (C10), between the No. B4 (15 A) fuse and PGM-FI main relay 2, or between the No. B4 (15 A) fuse and the immobilizer control unit (or keyless access control unit). Also replace the No. B4 (15 A) fuse.
-NO- The IG1/IG1_FUEL_PUMP wire is OK. Replace the No. B4 (15 A) fuse, and update the PCM PCM Update if it does not have the latest software, or substitute a known-good PCM Service and Repair, then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM Service and Repair.

12. Shorted wire check (FUEL_PUMP_RLY_OUT line):

Shorted wire check (FUEL_PUMP_RLY_OUT line)
-1. Disconnect the following connector.





-2. Check for continuity between test points 1 and 2.









Is there continuity?
-YES-
* Repair a short in the FUEL_PUMP_RLY_OUT wire between the floor harness 4P connector and PGM-FI main relay 2. Also replace the No. B4 (15 A) fuse.
* Check the fuel tank unit subharness, and repair it if needed.
-NO- The FUEL_PUMP_RLY_OUT wire is OK. Check for following part(s):
* Check the fuel pump, and replace it if needed. Also replace the No. B4 IG1 FUEL PUMP (15 A) fuse.
* Check the fuel tank unit subharness, and repair it if needed. Also replace the No. B4 IG1 FUEL PUMP (15 A) fuse.

13. Open wire check (IG1, IG1_FUEL_PUMP lines):

Open wire check (IG1, IG1_FUEL_PUMP lines)
-1. Jump the SCS line with the HDS.

-2. Disconnect the following connectors.





-3. Turn the ignition switch to ON (II).

-4. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- The IG1/IG1_FUEL_PUMP wires are OK. Go to step 14.
-NO- Repair an open in the IG1/IG1_FUEL_PUMP wire between the No. B4 (15 A) fuse and the PCM (C10).

14. Determine possible failure area (FI_MAIN_RLY_CL- line, others):

Determine possible failure area (FI_MAIN_RLY_CL- line, others)
-1. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- Go to step 18.
-NO- Go to step 15.

15. Determine possible failure area (+B_IGP line, others):

Determine possible failure area (+B_IGP line, others)
-1. Turn the ignition switch to LOCK (0).

-2. Remove PGM-FI main relay 1 (A) from the under-dash fuse/relay box.





-3. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- Go to step 17.
-NO- Go to step 16.

16. Open wire check (+B_IGP line):

Open wire check (+B_IGP line)
-1. Disconnect the following connector.





-2. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- Repair an open the +B_IGP wire between the No. A21 (15A) fuse and under-dash fuse/relay box.
-NO- The +B_IGP wire is OK. Replace the under-hood fuse/relay box.

17. Open wire check (FI_MAIN_RLY_CL- line):

Open wire check (FI_MAIN_RLY_CL- line)
-1. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- The FI_MAIN_RLY_CL- wire is OK. Test PGM-FI main relay 1. If the relay is OK, update the PCM PCM Update if it does not have the latest software, or substitute a known-good PCM Service and Repair, then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM Service and Repair.
-NO- Repair an open in the FI_MAIN_RLY_CL- wire between the PCM (A6) and PGM-FI main relay 1.

18. Determine possible failure area (+B_IGP line, others):

Determine possible failure area (+B_IGP line, others)
-1. Turn the ignition switch to LOCK (0).

-2. Remove PGM-FI main relay 1 (A) from the under-dash fuse/relay box.





-3. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- Go to step 20.
-NO- Go to step 19.

19. Open wire check (+B_IGP line):

Open wire check (+B_IGP line)
-1. Disconnect the following connector.





-2. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- Repair an open the +B_IGP wire between the No. A21 (15A) fuse and under-dash fuse/relay box.
-NO- The +B_IGP wire is OK. Replace the under-hood fuse/relay box.

20. Open wire check (FI_MAIN_RLY_OUT line):

Open wire check (FI_MAIN_RLY_OUT line)
-1. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- The FI_MAIN_RLY_OUT wire is OK. Go to step 21.
-NO- Repair an open in the FI_MAIN_RLY_OUT wire between the PCM (A9) and PGM-FI main relay 1.

21. Relay test:

Relay test
-1. Test PGM-FI main relay 1 Testing and Inspection.

Is PGM-FI main relay 1 OK?
-YES- PGM-FI main relay 1 is OK. Go to step 22.
-NO- Replace PGM-FI main relay 1.

22. Open wire check (ground line):

Open wire check (ground line)
-1. Disconnect the following connector.





-2. Check for continuity between these test points and body ground individually.


















Is there continuity?
-YES- The PG1, PG2, LG1, and LG2 wires are OK. Update the PCM PCM Update if it does not have the latest software, or substitute a known-good PCM Service and Repair, then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM Service and Repair.
-NO- Repair an open in the PG1, PG2, LG1, or LG2 wire between the PCM (B1, B20, C2, C15, C20) and G101.