DTC Troubleshooting: P0657 (L15B7/L15BA/L15BY)

1.

Problem verification:

Problem verification

?1.	Turn the vehicle to the ON mode.

?2.	Clear the DTC with the HDS.

?3.	Start the engine.

?4.

Check for Pending or Confirmed DTCs with the HDS.

DTC Description	Confirmed DTC	Pending DTC
P0657 PCM Power Supply Circuit Malfunction

Is DTC P0657 indicated?


	YES

The failure is duplicated. Go to step 2.


	NO

Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the relay circuit board and the PCM. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot.?

2.

Relay circuit board check:

Relay circuit board check

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

?2.	Remove and test the relay circuit board.

Is the relay circuit board OK?


	YES

Go to step 3.


	NO

Replace the relay circuit board.?

3.

Fuse check:

Fuse check

?1.

Check the following fuse.

Fuse	No. A7 (15 A)
Location	Under-hood fuse/relay box

Is the fuse OK?


	YES

Go to step 7.


	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. A7 (15 A) fuse from the under-hood fuse/relay box.

?2.	Remove the injector relay.

?3.

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

Test condition	Vehicle OFF (LOCK) mode
	Relay circuit board: removed
	Injector relay: disconnected

Connector	Terminal
Relay circuit board connector C (18P)	No. 18
Injector relay 4P socket	No. 7

Is there continuity?


	YES

Repair a short in the +B IGP wire between the No. A7 (15 A) fuse in the under-hood fuse/relay box and the relay circuit board and the injector relay. Also replace the No. A7 (15 A) fuse.?


	NO

Go to step 5.

5.

Parts internal circuit check:

Parts internal circuit check

?1.	Jump the SCS line with the HDS, and wait more than 1 minute.

?2.

Check for continuity between test points 1 and 2 while disconnecting these parts, one at a time:

	PGM-FI main relay 2
	PCM connector A (50P)

Test condition	Vehicle OFF (LOCK) mode
	Relay circuit board: removed
Test point 1	Relay circuit board connector C (18P) No. 17
Test point 2	Body ground

Does continuity go away with the part(s) removed?


	YES

Replace the part that continuity goes away when it was disconnected. If the part is PCM, Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. If DTC P0657 goes away and the PCM was substituted, replace the original PCM. Also replace the No. A7 (15 A) fuse.?


	NO

Go to step 6.

6.

Shorted wire check (FI MAIN RLY OUT line):

Shorted wire check (FI MAIN RLY OUT line)

?1.

Disconnect the following connectors.

PGM-FI main relay 2

PCM connector A (50P)

?2.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Relay circuit board: removed
	PGM-FI main relay 2: disconnected
	PCM connector A (50P): disconnected
Test point 1	PCM connector A (50P) No. 8
Test point 2	Body ground

Is there continuity?


	YES

Repair a short in the FI MAIN RLY OUT line between the relay circuit board, PGM-FI main relay 2, and the PCM (A8). Also replace the No. A7 (15 A) fuse.?


	NO

Replace the relay circuit board. Also replace the No. A7 (15 A) fuse in the under-hood fuse/relay box.?

7.

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

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

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

?2.	Install the relay circuit board.

?3.	Jump the SCS line with the HDS, and wait more than 1 minute.

?4.

Disconnect the following connector.

PCM connector A (50P)

?5.

Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	PCM connector A (50P): disconnected
Test point 1	PCM connector A (50P) No. 5
Test point 2	Body ground

Is there battery voltage?


	YES

Go to step 10.


	NO

Go to step 8.

8.

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

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

?1.

Disconnect the following connector.

Relay circuit board connector C (18P)

?2.

Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	PCM connector A (50P): disconnected
	Relay circuit board connector C (18P): disconnected
Test point 1	Relay circuit board connector C (18P) No. 18
Test point 2	Body ground

Is there battery voltage?


	YES

Go to step 9.


	NO

Repair an open in the +B IGP wire between the No. A7 (15 A) fuse in the under-hood fuse/relay box and the relay circuit board.?

9.

Open wire check (FI MAIN RLY CL- line):

Open wire check (FI MAIN RLY CL- line)

?1.

Connect terminals A and B with a jumper wire.

Terminal A	Relay circuit board connector C (18P) No. 5
Terminal B	Body ground

?2.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	PCM connector A (50P): disconnected
	Relay circuit board connector C (18P): disconnected
	Relay circuit board connector C (18P) No. 5: jumped to body ground
Test point 1	PCM connector A (50P) No. 5
Test point 2	Body ground

Is there continuity?


	YES

Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. If DTC P0657 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 (A5) and the relay circuit board.?

10.

Open wire check (FI MAIN RLY OUT line):

Open wire check (FI MAIN RLY OUT line)

?1.

Disconnect the following connector.

Relay circuit board connector C (18P)

?2.

Connect terminals A and B with a jumper wire.

Terminal A	Relay circuit board connector C (18P) No. 17
Terminal B	Body ground

?3.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	PCM connector A (50P): disconnected
	Relay circuit board connector C (18P): disconnected
	Relay circuit board connector C (18P) No. 17: jumped to body ground
Test point 1	PCM connector A (50P) No. 8
Test point 2	Body ground

Is there continuity?


	YES

Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. If DTC P0657 goes away and the PCM was substituted, replace the original PCM.?


	NO

Repair an open in the FI MAIN RLY OUT wire between the PCM (A8) and relay circuit board.?