PCM Power and Ground Circuit (R20A5) (2013 2014 2015)

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. Determine possible failure area (+B IG MAIN wire shroted, others)

   -1. Press the engine start/stop button to select the OFF mode.

   -2. Check the following fuse.

   Fuse	No. A2-1 (50 A)
   Location	Under-hood fuse/relay box

   Is the fuse OK?

   YES 

   Check for an open in the +B IG MAIN wire between the No. A2-1 (50 A) fuse in the under-hood fuse/relay box and the ignition switch. Go to step 3.

   NO 

   Repair a short in the +B IG MAIN wire between the No. A2-1 (50 A) fuse and the under-hood fuse/relay box. Also replace the No. A2-1 (50 A) fuse.

3. Fuse check

   -1. Press the engine start/stop button to select the OFF mode.

   -2. Check the following fuse.

   Fuse	No. A21 (15 A)
   Location	Under-hood fuse/relay box

   Is the fuse OK?

   YES 

   Go to step 8.

   NO 

   Go to step 4.

4. 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.

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

   Test condition	OFF mode
   	PGM-FI main relay 1: disconnected
   Test circuit	+B IGP
   Test point 1	PGM-FI main relay 1 4P socket No. 1
   Test point 2	Body ground

   Test circuit	+B IGP
   Test point 1	PGM-FI main relay 1 4P socket No. 4
   Test point 2	Body ground

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   Is there continuity?

   YES 

   Go to step 5.

   NO 

   Go to step 6.

5. Shorted wire check (+B IGP line)

   -1. Disconnect the following connector.

   Under-dash fuse/relay box connector D (32P)

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

   Test condition	OFF mode
   	PGM-FI main relay 1: disconnected
   	Under-dash fuse/relay box connector D (32P): disconnected
   Test circuit	+B IGP
   Test point 1	Under-dash fuse/relay box connector D (32P) No. 8 (BLU)
   Test point 2	Body ground

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   Is there continuity?

   YES 

   Repair a short the +B IGP wire between the No. A21 (15 A) fuse in the under-hood fuse/relay box and the under-dash fuse/relay box. Also replace the No. A21 (15 A) fuse.

   NO 

   The +B IGP wire is OK. Replace the under-hood fuse/relay box. Also replace the No. A21 (15 A) fuse in the under-hood fuse/relay box.

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

   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 (49P)
   • Each injector 2P connector
   • CMP sensor 3P connector
   • CKP sensor 3P connector
   • Electronic throttle control system (ETCS) control relay

   Test condition	OFF mode
   Test circuit	FI MAIN RLY OUT
   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. A21 (15 A) fuse in the under-hood fuse/relay box.

   NO 

   Parts are OK. Go to step 7.

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

   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 (49P)
   • Each injector 2P connector
   • CMP sensor 3P connector
   • CKP sensor 3P connector
   • Electronic throttle control system (ETCS) control relay

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

   Test condition	OFF mode
   	PGM-FI main relay 1: disconnected
   	PGM-FI main relay 2: disconnected
   	PCM connector A (49P): 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 circuit	FI MAIN RLY OUT
   Test point 1	PGM-FI main relay 1 4P socket No. 2
   Test point 2	Body ground

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   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. A21 (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. A21 (15 A) fuse in the under-hood fuse/relay box.

8. Fuse check 2

   -1. Check the following fuse.

   Fuse	No. B4 (15 A)
   Location	Under-dash fuse/relay box

   Is the fuse OK?

   YES 

   Go to step 13.

   NO 

   Go to step 9.

9. Relay check

   -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 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 10.

   NO 

   Replace PGM-FI main relay 2. Also replace the No. B4 (15 A) fuse in the under-dash fuse/relay box.

10. Determine possible failure area (IG1 FUEL PUMP line, others)

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

    Test condition	OFF mode
    	PGM-FI main relay 2: disconnected
    Test circuit	IG1 FUEL PUMP
    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 11.

    NO 

    Go to step 12.

11. 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 C (49P)

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

    Test condition	OFF mode
    	PGM-FI main relay 2: disconnected
    	PCM connector C (49P): disconnected
    Test circuit	IG1(F/PUMP)
    Test point 1	PCM connector C (49P) No. 10 (BLK/YEL)
    Test point 2	Body ground

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    Is there continuity?

    YES 

    Repair a short in the IG1(F/PUMP)/IG1 FUEL PUMP wire between the No. B4 (15 A) fuse in the under-dash fuse/relay box 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. Also replace the No. B4 (15 A) fuse.

    NO 

    The IG1(F/PUMP)/IG1 FUEL PUMP wire is OK. Replace the No. B4 (15 A) fuse in the under-dash fuse/relay box, 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 .

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

    -1. Remove the access panel from the floor .

    -2. Disconnect the following connector.

    Fuel tank unit 4P connector

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

    Test condition	OFF mode
    	PGM-FI main relay 2: disconnected
    	Fuel tank unit 4P connector: disconnected
    Test circuit	FUEL PUMP RLY OUT
    Test point 1	Fuel tank unit 4P connector No. 1 (GRN)
    Test point 2	Body ground

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    Is there continuity?

    YES 

    Repair a short in the FUEL PUMP RLY OUT wire between the fuel tank unit 4P connector and PGM-FI main relay 2. Also replace the No. B4 (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. B4 (15 A) fuse in the under-dash fuse/relay box.

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

    -1. Jump the SCS line with the HDS.

    -2. Disconnect the following connectors.

    PCM connector C (49P)

    -3. Press the engine start/stop button to select the ON mode.

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

    Test condition

    ON mode

    	PCM connector C (49P): disconnected
    Test circuit	IG1(F/PUMP)
    Test point 1	PCM connector C (49P) No. 10 (BLK/YEL)
    Test point 2	Body ground

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    Is there battery voltage?

    YES 

    The IG1(F/PUMP)/IG1 FUEL PUMP wire is OK. Go to step 14.

    NO 

    Repair an open in the IG1(F/PUMP)/IG1 FUEL PUMP wire between the No. B4 (15 A) fuse in the under-dash fuse/relay box and the PCM (C10).

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

    -1. Press the engine start/stop button to select the OFF mode.

    -2. Jump the SCS line with the HDS.

    -3. Disconnect the following connectors.

    PCM connector A (49P)

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

    Test condition	OFF mode
    	PCM connector A (49P): disconnected
    	PCM connector C (49P): disconnected
    Test circuit	FI MAIN RLY CL-
    Test point 1	PCM connectors A (49P) No. 7 (GRN)
    Test point 2	Body ground

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    Is there battery voltage?

    YES 

    Go to step 18.

    NO 

    Go to step 15.

15. Determine possible failure area (+B IGP line, others)

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

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

    Test condition	OFF mode
    	PCM connector A (49P): disconnected
    	PCM connector C (49P): disconnected
    	PGM-FI main relay 1: disconnected
    Test circuit	+B IGP
    Test point 1	PGM-FI main relay 1 4P socket No. 4
    Test point 2	Body ground

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    Is there battery voltage?

    YES 

    Go to step 17.

    NO 

    Go to step 16.

16. Open wire check (+B IGP line)

    -1. Disconnect the following connector.

    Under-dash fuse/relay box connector D (32P)

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

    Test condition	OFF mode
    	PCM connector A (49P): disconnected
    	PCM connector C (49P): disconnected
    	PGM-FI main relay 1: disconnected
    	Under-dash fuse/relay box connector D (32P): disconnected
    Test circuit	+B IGP
    Test point 1	Under-dash fuse/relay box connector D (32P) No. 8 (BLU)
    Test point 2	Body ground

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    Is there battery voltage?

    YES 

    The +B IGP wire is OK. Replace the under-hood fuse/relay box.

    NO 

    Repair an open the +B IGP wire between the No. A21 (15A) fuse and the under-dash fuse/relay box.

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

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

    Test condition	OFF mode
    	PCM connector A (49P): disconnected
    	PCM connector C (49P): disconnected
    	PGM-FI main relay 1: disconnected
    Test circuit	FI MAIN RLY CL-
    Test point 1	PGM-FI main relay 1 4P socket No. 3
    Test point 2	PCM connector A (49P) No. 7 (GRN)

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    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.

18. Determine possible failure area (+B IGP line, others)

    -1. Press the engine start/stop button to select the OFF mode.

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

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

    Test condition	OFF mode
    	PCM connector A (49P): disconnected
    	PCM connector C (49P): disconnected
    	PGM-FI main relay 1: disconnected
    Test circuit	+B IGP
    Test point 1	PGM-FI main relay 1 4P socket No. 1
    Test point 2	Body ground

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    Is there battery voltage?

    YES 

    Go to step 20.

    NO 

    Go to step 19.

19. Open wire check (+B IGP line)

    -1. Disconnect the following connector.

    Under-dash fuse/relay box connector D (32P)

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

    Test condition	OFF mode
    	PCM connector A (49P): disconnected
    	PCM connector C (49P): disconnected
    	PGM-FI main relay 1: disconnected
    	Under-dash fuse/relay box connector D: disconnected
    Test circuit	+B IGP
    Test point 1	Under-dash fuse/relay box connector D (32P) No. 8 (BLU)
    Test point 2	Body ground

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    Is there battery voltage?

    YES 

    The +B IGP wire is OK. Replace the under-hood fuse/relay box .

    NO 

    Repair an open in the +B IGP wire between the No. A21 (15 A) fuse in the under-hood fuse/relay box and the under-dash fuse/relay box.

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

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

    Test condition	OFF mode
    	PCM connector A (49P): disconnected
    	PCM connector C (49P): disconnected
    	PGM-FI main relay 1: disconnected
    Test circuit	FI MAIN RLY OUT
    Test point 1	PGM-FI main relay 1 4P socket terminal No. 2
    Test point 2	PCM connector A (49P) No. 9 (ORN)

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    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 check

    -1. Test PGM-FI main relay 1 .

    Is the relay OK?

    YES 

    PGM-FI main relay 1 is OK. Go to step 22.

    NO 

    Replace PGM-FI main relay 1.

22. Open wire check (PG, LG lines)

    -1. Disconnect the following connector.

    PCM connectors B (49P)

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

    Test condition	OFF mode
    	PCM connector A (49P): disconnected

    	PCM connector B (49P): disconnected
    	PCM connector C (49P): disconnected
    	PGM-FI main relay 1: disconnected

    Connector	Test circuit	Terminal
    PCM connector B (49P)	PG	No. 1 (BLK)
    	PG	No. 10 (BLK)
    PCM connector C (49P)	PG	No. 2 (BLK)
    	LG	No. 15 (BRN/YEL)
    	LG	No. 20 (BRN/YEL)

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    Is there continuity?

    YES 

    The PG and LG 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 wire between the PCM (B1, B10, C2, C15, C20) and G101.