DTC Troubleshooting: P1659 (L15B7/L15BY) - Honda Civic FC/FK 2016-2021

1.

Problem verification:

Problem verification

?1.	Turn the vehicle to the ON mode.

?2.	Clear the DTC with the HDS.

?3.

Check for Pending or Confirmed DTCs with the HDS.

DTC Description	Confirmed DTC	Pending DTC
P1659 ETCS Control Relay OFF Malfunction

Is DTC P1659 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.	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.	Turn the vehicle to the OFF (LOCK) mode.

?2.

Check the following fuse.

Fuse	No. A8 (15 A)
Location	Under-hood fuse/relay box

Is the fuse OK?


	YES

Go to step 4.


	NO

Go to step 7.

4.

Open wire check (+B DBW line):

Open wire check (+B DBW line)

?1.

Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Relay circuit board: removed
Test point 1	Relay circuit board connector C (18P) No. 14
Test point 2	Body ground

Is there battery voltage?


	YES

The +B DBW wire is OK. Go to step 5.


	NO

Repair an open in the +B DBW wire between the No. A8 (15 A) fuse in the under-hood fuse/relay box and the relay circuit board. If needed, replace the under-hood fuse/relay box.?

5.

Open wire check (FI SUB RLY OUT line):

Open wire check (FI SUB RLY OUT line)

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

?2.

Disconnect the following connector.

PCM connector A (50P)

?3.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Relay circuit board: removed
	PCM connector A (50P): disconnected
Test point 1	Relay circuit board connector C (18P) No. 11
Test point 2	PCM connector A (50P) No. 16

Is there continuity?


	YES

The FI SUB RLY OUT wire is OK. Go to step 6.


	NO

Repair an open in the FI SUB RLY OUT wire between the PCM (A16) and the relay circuit board.?

6.

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

Open wire check (FI SUB RLY CL- line)

?1.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Relay circuit board: removed
	PCM connector A (50P): disconnected
Test point 1	Relay circuit board connector B (6P) No. 2
Test point 2	PCM connector A (50P) No. 25

Is there continuity?


	YES

The FI SUB RLY CL- wire is OK. 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 P1659 goes away and the PCM was substituted, replace the original PCM.?


	NO

Repair an open in the FI SUB RLY CL- wire between the PCM (A25) and the relay circuit board.?

7.

Shorted wire check (FI SUB RLY OUT line):

Shorted wire check (FI SUB RLY OUT line)

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

?2.

Disconnect the following connectors.

PCM connector A (50P)

?3.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Relay circuit board: removed
	PCM connector A (50P): disconnected
Test point 1	PCM connector A (50P) No. 16
Test point 2	Body ground

Is there continuity?


	YES

Repair a short in the FI SUB RLY OUT wire between the PCM (A16) and the relay circuit board. Also replace the No. A8 (15 A) in the under-hood fuse/relay box.?


	NO

The FI SUB RLY OUT wire is OK. Go to step 8.

8.

Shorted wire check (+B DBW line):

Shorted wire check (+B DBW line)

?1.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Relay circuit board: removed
	PCM connector A (50P): disconnected
Test point 1	Relay circuit board connector C (18P) No. 14
Test point 2	Body ground

Is there continuity?


	YES

Repair a short in the +B DBW wire between the No. A8 (15 A) fuse in the under-hood fuse/relay box and the relay circuit board. If needed, replace the under-hood fuse/relay box. Also replace the No. A8 (15 A) fuse under-hood fuse/relay box.?


	NO

The +B DBW wire is OK. 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 P1659 goes away and the PCM was substituted, replace the original PCM. Also replace the No. A8 (15 A) fuse in the under-hood fuse/relay box.?