DTC P0979

DTC P0979  : Shift Solenoid Valve C (Short)

NOTE: Before you troubleshoot, review the General Troubleshooting Information - Refer to: How to Troubleshoot the Fuel and Emissions Systems, or How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016), or How to Troubleshoot the A/T System (2014 2015) .
• 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 (A/T)

1. Problem verification

   -1. Turn the vehicle to 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. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.

2. Fuse check

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

   - 2. Check the following fuse.

   Fuse	No. C5 (7.5 A)
   Location	Under-hood fuse/relay box

   Is the fuse OK?

   YES 

   The fuse is OK. Go to step 3.

   NO 

   Replace the No. C5 (7.5 A) fuse, and recheck. If the fuse blows again, repair a short to ground on the No. C5 (7.5 A) fuse circuit, and recheck.

3. Open wire check (IG1 VBSOL (7.5 A) line)

   -1. Jump the SCS line with the HDS.

   - 2. Disconnect the following connector.

   PCM connector A (51P) - Refer to: How to Troubleshoot the Fuel and Emissions Systems, or How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016), or How to Troubleshoot the A/T System (2014 2015)

   - 3. Turn the vehicle to the ON mode.

   - 4. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode
   	PCM connector A (51P): disconnected
   Test circuit	IG1 VBSOL (7.5 A)
   Test point 1	PCM connector A (51P) No. 1 (PUR)
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there battery voltage?

   YES 

   The IG1 VBSOL (7.5 A) Wire is OK. Go to step 4.

   NO 

   Repair an open in the IG1 VBSOL (7.5 A) wire between the PCM and the No. C5(7.5 A) fuse in the under-hood fuse/relay box.

4. Determine possible failure area (shift solenoid valve C, others)

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

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

   - 3. Disconnect the following connector.

   Shift solenoid valve C 2P connector

   - 4. Turn the vehicle to 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 

   Replace shift solenoid valve C .

5. Shorted wire check (SHC line)

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

   - 2. Jump the SCS line with the HDS.

   - 3. Disconnect the following connector.

   PCM connector B (51P) - Refer to: How to Troubleshoot the Fuel and Emissions Systems, or How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016), or How to Troubleshoot the A/T System (2014 2015)

   - 4. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) 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

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Repair a short to ground in the SHC wire between shift solenoid valve C and the PCM.

   NO 

   The SHC wire is OK. Replace the PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) .