DTC Troubleshooting: P0979
DTC P0979: Shift Solenoid Valve C (Short)
NOTE:
Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, and review the General Troubleshooting Information.
This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.
If DTC P0979 is stored in the PCM, the transmission does not shift to 2nd or 5th gear because of the fail-safe function.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0979 Shift Solenoid Valve C (Short)
      

1.
Problem verification:

Problem verification
?1.
Press the engine start/stop button to select the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Start the engine in P, and wait for at least 1 second.

?4.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0979 Shift Solenoid Valve C (Short)
      

Is DTC P0979 indicated?

     
YES
     
     
     
The failure is duplicated. Go to step 2.
     
NO
     
     
     
Intermittent failure, the system is OK at this time. Check for poor connections and loose terminals between shift solenoid valve C and the PCM.?
2.
Fuse check:

Fuse check
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Check the following fuse.
Fuse
No. B8 (10 A)
Location
Under-dash fuse/relay box

Is the fuse OK?

     
YES
     
     
     
The fuse is OK. Go to step 3.
     
NO
     
     
     
Replace the No. B8 (10 A) fuse, and recheck. If the fuse blows again, repair a short to body ground on the No. B8 (10 A) fuse circuit, and recheck.?
3.
Open wire check (IG1 MISS SOL line):

Open wire check (IG1 MISS SOL line)
?1.
Jump the SCS line with the HDS.


?2.
Disconnect the following connector.

?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 A (51P): disconnected
Test circuit
IG1 MISS SOL
Test point 1
PCM connector A (51P) No. 1 (LT BLU)
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The IG1 MISS SOL wire is OK. Go to step 4.
     
NO
     
     
     
Repair an open in the IG1 MISS SOL wire between the PCM and the No. B8 (10 A) fuse in the under-dash fuse/relay box.?
4.
Determine possible failure area (shift solenoid valve C, others):

Determine possible failure area (shift solenoid valve C, others)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Reconnect PCM connector A (51P).

?3.
Disconnect the following connector.

?4.
Press the engine start/stop button to select the ON mode.

?5.
Clear the DTC with the HDS.


?6.
Start the engine in P, and wait for at least 1 second.

?7.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0979 Shift Solenoid Valve C (Short)
      

Is DTC P0979 indicated?

     
YES
     
     
     
Shift solenoid valve C is OK. Go to step 5.
     
NO
     
     
     
5.
Shorted wire check (SHC line):

Shorted wire check (SHC line)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Jump the SCS line with the HDS.


?3.
Disconnect the following connector.

?4.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
 
Shift solenoid valve C 2P connector: disconnected
 
PCM connector B (51P): disconnected
Test circuit
SHC
Test point 1
PCM connector B (51P) No. 3 (GRN)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short to body ground in the SHC wire between shift solenoid valve C and the PCM.?
     
NO
     
     
     
The SHC wire is OK. Replace the PCM.?