DTC Troubleshooting: P068B
DTC P068B: PCM Power Source Circuit Unexpected Voltage
NOTE: Before you troubleshoot, review the general troubleshooting information.

DTC Description
Confirmed DTC
Pending DTC
P068B PCM Power Source Circuit Unexpected Voltage
    

1.
Problem verification:

Problem verification
?1.
Turn the vehicle to the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Turn the vehicle to the OFF (LOCK) mode.

?4.
Wait 10 seconds.

?5.
Turn the vehicle to the ON mode.

?6.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
P068B PCM Power Source Circuit Unexpected Voltage
    

Is DTC P068B 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 main relay 1 circuit) 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.
Determine possible failure area (FI MAIN RLY CL- line, others):

Determine possible failure area (FI MAIN RLY CL- line, others)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Jump the SCS line with the HDS, and wait more than 1 minute.


?3.
Disconnect the following connector.
PCM connector No. 2 (58P)

?4.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
PCM connector No. 2 (58P): disconnected
Test point 1
PCM connector No. 2 (58P) No. 26
Test point 2
Body ground

Is there battery voltage?

     
YES
     
     
     
Go to step 5.
     
NO
     
     
     
Go to step 3.
3.
Shorted wire check (FI MAIN RLY CL- line):

Shorted wire check (FI MAIN RLY CL- line)
?1.
Disconnect the following connector.
Relay circuit board connector C (18P)

?2.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
PCM connector No. 2 (58P): disconnected
 
Relay circuit board connector C (18P): disconnected
Test point 1
PCM connector No. 2 (58P) No. 26
Test point 2
Body ground

Is there continuity?

     
YES
     
     
     
Repair a short in the FI MAIN RLY CL- wire between PCM connector No. 2 terminal No. 26 and the relay circuit board.?
     
NO
     
     
     
The FI MAIN RLY CL- wire is OK. Go to step 4.
4.
Relay circuit board check:

Relay circuit board check
?1.
Remove and test the relay circuit board.

Is the relay circuit board OK?

     
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 P068B goes away and the PCM was substituted, replace the original PCM.?
     
NO
     
     
     
5.
Shorted wire check (FI MAIN RLY OUT line to power):

Shorted wire check (FI MAIN RLY OUT line to power)
?1.
Remove PGM-FI main relay 2.

?2.
Disconnect the following connector.
Relay circuit board connector C (18P)

?3.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
PCM connector No. 2 (58P): disconnected
PGM-FI main relay 2: disconnected
 
Relay circuit board connector C (18P): disconnected
Test point 1
PCM connector No. 2 (58P) No. 2, No. 4, and No. 6
Test point 2
Body ground

Is there battery voltage?

     
YES
     
     
     
Repair a short to power in the FI MAIN RLY OUT wire between PCM connector No. 2 terminals (No. 2, No. 4, No. 6), PGM-FI main relay 2, and the relay circuit board.?
     
NO
     
     
     
The FI MAIN RLY OUT wire is OK. Go to step 6.
6.
Relay circuit board check:

Relay circuit board check
?1.
Remove and test the relay circuit board.

Is the relay circuit board OK?

     
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 P068B goes away and the PCM was substituted, replace the original PCM.?
     
NO