PCM Power and Ground Circuit Troubleshooting

PCM Power and Ground Circuit Troubleshooting 

1. Engine starting check

   -1. Try to start the engine.

   Does the engine start and idle smoothly?

   YES 

   Go to the F-CAN circuit troubleshooting .

   NO 

   Go to step 2.

2. Fuse check

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Check the following fuse.

   Fuse	No. B7 (15 A)
   Location	Under-hood fuse/relay box

   Is the fuse OK?

   YES 

   Go to step 6.

   NO 

   Go to step 3.

3. Shorted wire check (+B IGP line)

   -1. Remove the blown No. B7 (15 A) fuse from the under-hood fuse/relay box.

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

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

   Test condition	Vehicle OFF (LOCK) mode
   	PGM-FI main relay 1: disconnected
   Test point 1	PGM-FI main relay 1 4P socket No. 1 and No. 3
   Test point 2	Body ground

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   Is there continuity?

   YES 

   Repair a short in the +B IGP wire between PGM-FI main relay 1 and the No. B7 (15 A) fuse. If the wire is OK, replace the under-hood fuse/relay box . Also replace the No. B7 (15 A) fuse.

   NO 

   Go to step 4.

4. Part (s) internal circuit check (short in FI MAIN RLY OUT line)

   -1. Jump the SCS line with the HDS.

   -2. Disconnect each of the parts or connectors below, one at a time, then check for continuity between test points 1 and 2.

   • PGM-FI main relay 2
   • PCM connector A (51P)
   • Each injector 2P connector
   • CMP sensor 3P connector
   • CKP sensor 3P connector
   • Electronic throttle control system (ETCS) control relay

   Test condition	Vehicle OFF (LOCK) mode
   Test point 1	PGM-FI main relay 1 4P socket No. 2
   Test point 2	Body ground

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   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  if it does not have the latest software, or substitute a known-good PCM , 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 . Also replace the No. B7 (15 A) fuse in the under-hood fuse/relay box.

   NO 

   Parts are OK. Go to step 5.

5. Shorted wire check (FI MAIN RLY OUT line):

   -1. Disconnect the following parts:

   • PGM-FI main relay 2
   • PCM connector A (51P)
   • Injectors
   • CMP sensor
   • CKP sensor
   • Electronic throttle control system (ETCS) control relay

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

   Test condition	Vehicle OFF (LOCK) mode
   	PGM-FI main relay 1: disconnected
   	PGM-FI main relay 2: disconnected
   	PCM connector A (51P): disconnected
   	Each injector 2P connector: disconnected
   	CMP sensor 3P connector: disconnected
   	CKP sensor 3P connector: disconnected
   	Electronic throttle control system (ETCS) control relay: disconnected
   Test point 1	PGM-FI main relay 1 4P socket No. 2
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Repair a short in the FI MAIN RLY OUT wire between PGM-FI main relay 1 and each part. Also replace the No. B7 (15 A) fuse in the under-hood fuse/relay box.

   NO 

   The FI MAIN RLY OUT wire is OK. Replace PGM-FI main relay 1. Also replace the No. B7 (15 A) fuse in the under-hood fuse/relay box.

6. Fuse check 2

   -1. Check the following fuse.

   Fuse	No. C32 (15 A)
   Location	Under-dash fuse/relay box

   Is the fuse OK?

   YES 

   Go to step 11.

   NO 

   Go to step 7.

7. Relay check

   -1. Remove the blown No. C32 (15 A) fuse from the under-dash fuse/relay box.

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

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   -3. Test PGM-FI main relay 2 .

   Is the relay OK?

   YES 

   PGM-FI main relay 2 is OK. Go to step 8.

   NO 

   Replace PGM-FI main relay 2. Also replace the No. C32 (15 A) fuse in the under-dash fuse/relay box.

8. Determine possible failure area (IG1 (F/PUMP)/IG1 FUEL PUMP line, others)

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

   Test condition	Vehicle OFF (LOCK) mode
   	PGM-FI main relay 2: disconnected
   Test point 1	PGM-FI main relay 2 4P socket No. 2
   Test point 2	Body ground

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   Is there continuity?

   YES 

   Go to step 9.

   NO 

   Go to step 10.

9. Shorted wire check (IG1 (F/PUMP)/IG1 FUEL PUMP line)

   -1. Jump the SCS line with the HDS.

   -2. Disconnect the following connector.

   PCM connector B (51P)

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

   Test condition	Vehicle OFF (LOCK) mode
   	PGM-FI main relay 2: disconnected
   	PCM connector B (51P): disconnected
   Test point 1	PCM connector B (51P) No. 3
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short in the IG1 (F/PUMP)/IG1 FUEL PUMP wire between the No. C32 (15 A) fuse and the PCM (B3). Also replace the No. C32 (15 A) fuse.

   NO 

   The IG1 (F/PUMP)/IG1 FUEL PUMP wire is OK. Replace the No. C32 (15 A) fuse, and update the PCM  if it does not have the latest software, or substitute a known-good PCM , 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 .

10. Shorted wire check (FUEL PUMP RLY OUT line)

    -1. Disconnect the following connector.

    Fuel tank unit 4P connector

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

    Test condition	Vehicle OFF (LOCK) mode
    	PGM-FI main relay 2: disconnected
    	Fuel tank unit 4P connector: disconnected
    Test point 1	PGM-FI main relay 2 4P socket No. 1
    Test point 2	Body ground

    Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Repair a short in the FUEL PUMP RLY OUT wire between PGM-FI main relay 2 and the fuel tank unit. Also replace the No. C32 (15 A) fuse in the under-dash fuse/relay box.

    NO 

    The FUEL PUMP RLY OUT wire is OK. Check the fuel pump, and replace it if needed. Also replace the No. C32 (15 A) fuse in the under-dash fuse/relay box.

11. Open wire check (IG1 (F/PUMP)/IG1 FUEL PUMP line)

    -1. Jump the SCS line with the HDS.

    -2. Disconnect the following connector.

    PCM connector B (51P)

    -3. Turn the vehicle to the ON mode.

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

    Test condition	Vehicle ON mode
    	PCM connector B (51P): disconnected
    Test point 1	PCM connector B (51P) No. 3
    Test point 2	Body ground

    Is there battery voltage?

    YES 

    The IG1 (F/PUMP)/IG1 FUEL PUMP wire is OK. Go to step 12.

    NO 

    Repair an open in the IG1 (F/PUMP)/IG1 FUEL PUMP wire between the No. C32 (15 A) fuse and the PCM (B3).

12. Determine possible failure area (PGM-FI main relay 1 control circuit, others)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Jump the SCS line with the HDS.

    -3. Disconnect the following connector.

    PCM connector A (51P)

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

    Test condition	Vehicle OFF mode
    	PCM connector A (51P): disconnected

    	PCM connector B (51P): disconnected
    Test point 1	PCM connector A (51P) No. 7
    Test point 2	Body ground

    Is there battery voltage?

    YES 

    Go to step 15.

    NO 

    Go to step 13.

13. Open wire check (+B IGP line)

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

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

    Test condition	Vehicle OFF (LOCK) mode
    	PCM connector A (51P): disconnected
    	PCM connector B (51P): disconnected
    	PGM-FI main relay 1: disconnected
    Test point 1	PGM-FI main relay 1 4P socket No. 3
    Test point 2	Body ground

    Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    Go to step 14.

    NO 

    Repair an open in the +B IGP wire between PGM-FI main relay 1 and the No. B7 (15 A) fuse in the under-hood fuse/relay box. If the wire is OK, replace the under-hood fuse/relay box . Also replace the No. B7 (15 A) fuse.

14. Open wire check (FI MAIN RLY CL- line)

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

    Test condition	Vehicle OFF (LOCK) mode
    	PCM connector A (51P): disconnected
    	PCM connector B (51P): disconnected
    	PGM-FI main relay 1: disconnected
    Test point 1	PGM-FI main relay 1 4P socket No. 4
    Test point 2	PCM connector A (51P) No. 7

    Courtesy of HONDA, U.S.A., INC.

    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  if it does not have the latest software, or substitute a known-good PCM , 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 .

    NO 

    Repair an open in the FI MAIN RLY CL- wire between the PCM (A7) and PGM-FI main relay 1.

15. Open wire check (+B IGP line)

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

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

    Test condition	Vehicle OFF (LOCK) mode
    	PCM connector A (51P): disconnected
    	PCM connector B (51P): disconnected
    	PGM-FI main relay 1: disconnected
    Test point 1	PGM-FI main relay 1 4P socket No. 1
    Test point 2	Body ground

    Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    Go to step 16.

    NO 

    Repair an open in the +B IGP wire between PGM-FI main relay 1 and the No. B7 (15 A) fuse in the under-hood fuse/relay box.

16. Open wire check (FI MAIN RLY OUT line)

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

    Test condition	Vehicle OFF (LOCK) mode
    	PCM connector A (51P): disconnected
    	PCM connector B (51P): disconnected
    	PGM-FI main relay 1: disconnected
    Test point 1	PGM-FI main relay 1 4P socket No. 2
    Test point 2	PCM connector A (51P) No. 9

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    Is there continuity?

    YES 

    The FI MAIN RLY OUT wire is OK. Go to step 17.

    NO 

    Repair an open in the FI MAIN RLY OUT wire between the PCM (A9) and PGM-FI main relay 1.

17. Relay check

    -1. Test PGM-FI main relay 1 .

    Is the relay OK?

    YES 

    PGM-FI main relay 1 is OK. Go to step 18.

    NO 

    Replace PGM-FI main relay 1.

18. Open wire check (PG (GND1), PG2 (GND3), PG, LG (GND2) lines)

    -1. Disconnect the following connector.

    PCM connector C (51P)

    -2. Check for continuity between the following PCM connector terminal and body ground individually.

    Test condition	Vehicle OFF (LOCK) mode
    	PCM connector A (51P): disconnected
    	PCM connector B (51P): disconnected
    	PCM connector C (51P): disconnected
    	PGM-FI main relay 1: disconnected

    Connector	Terminal
    PCM connector B (51P)	No. 1
    	No. 18
    PCM connector C (51P)	No. 2
    	No. 20

    Is there continuity?

    YES 

    The PG (GND1), PG2 (GND3), PG, and LG (GND2 wires are OK. Update the PCM  if it does not have the latest software, or substitute a known-good PCM , 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 .

    NO 

    Repair an open in the PG (GND1), PG2 (GND3), PG, or LG (GND2) wire between the PCM (B1, B18, C2, C20) and G101.