DTC Troubleshooting: P0687
DTC P0687: A/F Sensor (Sensor 1) Heater Power Source Circuit Short to Power
NOTE: Before you troubleshoot, review the general troubleshooting information.

DTC Description
Confirmed DTC
Pending DTC
P0687 A/F Sensor (Sensor 1) Heater Power Source Circuit Short to Power
    

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
P0687 A/F Sensor (Sensor 1) Heater Power Source Circuit Short to Power
    

Is DTC P0687 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 (PGM-FI subrelay circuit), the A/F sensor (Sensor 1), 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
     
     
     
3.
Shorted wire check (FI SUB RLY OUT/IGPS(LAF) line to power):

Shorted wire check (FI SUB RLY OUT/IGPS(LAF) line to power)
?1.
Disconnect the following connector.
A/F sensor (Sensor 1) 6P connector

?2.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Relay circuit board: removed
 
A/F sensor (Sensor 1) 6P connector: disconnected
Test point 1
Relay circuit board connector C (18P) (female terminals) No. 1:
Test point 2
Body ground


Is there any voltage?

     
YES
     
     
     
Repair a short to power in the FI SUB RLY OUT/IGPS(LAF) wire between the relay circuit board and the A/F sensor (Sensor 1).?
     
NO
     
     
     
The FI SUB RLY OUT/IGPS(LAF) wire is OK. Go to step 4.
4.
Shorted wire check (AFHT line to power):

Shorted wire check (AFHT line to power)
?1.
Jump the SCS line with the HDS, and wait more than 1 minute.


?2.
Disconnect the following connector.
PCM connector No. 1 (96P)

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Relay circuit board: removed
 
A/F sensor (Sensor 1) 6P connector: disconnected
 
PCM connector No. 1 (96P): disconnected
Test point 1
PCM connector No. 1 (96P) No. 16
Test point 2
Body ground

Is there any voltage?

     
YES
     
     
     
Repair a short to power in the AFHT wire between PCM connector No. 1 terminal No. 16 and the A/F sensor (Sensor 1).?
     
NO
     
     
     
The AFHT 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 P0687 goes away and the PCM was substituted, replace the original PCM.?