What this code means
P0977 may indicate that the ECM/PCM is detecting a possible electrical issue in the CVT shift solenoid valve B circuit.
What the vehicle may do
- The vehicle may have transmission shift complaints.
- The vehicle may store the code with limited driver-noticed symptoms.
Possible fault areas
- Possible connector or terminal concerns in the shift solenoid valve B circuit.
- Possible wiring opens between the solenoid harness and the PCM or solenoid.
- Possible shift solenoid valve B circuit or solenoid-related concern.
- Possible PCM software or PCM-related concern.
Diagnostic path
Opening context
On this 2010 to 2016 Honda CR-V with the 2.4 gas engine, P0977 points to the ECM/PCM seeing a possible problem in the CVT shift solenoid valve B circuit. The vehicle may have transmission shift complaints, or it may simply store the code with limited symptoms. The broad fault areas can include the solenoid circuit, connectors and terminals, wiring between the solenoid harness and the PCM, the solenoid assembly area, or possible PCM software or PCM-related concerns. Start with the basic system checks, and keep the main point in mind: this diagnostic path treats P0977 as an electrical circuit problem, not a mechanical transmission problem.
Verify the code first
First, duplicate the fault. Turn the vehicle to ON mode, clear the DTC with the HDS, start the engine in P, and wait for at least 10 seconds. Then check for pending or confirmed codes with the HDS. If P0977 comes right back, the failure is duplicated and you move into the circuit test. If it does not come back, treat it as an intermittent at this time. Check for poor connections or loose terminals in the shift solenoid valve B circuit area, and if captured data is available, try to reproduce the same operating conditions instead of guessing.
Check the shift solenoid valve B circuit from the PCM side
With the fault duplicated, turn the vehicle to OFF, or LOCK, mode. Jump the SCS line with the HDS and wait more than 1 minute. Disconnect PCM connector C, the 51P connector. Now measure resistance between PCM connector C terminal No. 19 and body ground. The expected reading is 10.6－13.5 Ω. If the reading is in that range, the shift solenoid valve B circuit checks OK from this point. The next move is PCM-side: update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If P0977 goes away after the update, the troubleshooting is complete. If it goes away with the known-good PCM substituted, replace the original PCM. If the resistance is not 10.6－13.5 Ω, continue into the harness open check.
Check the SOL B wire for an open
Next, disconnect solenoid wire harness A, the 8P connector. Check continuity between solenoid wire harness A connector terminal No. 5 and PCM connector C terminal No. 19. If there is no continuity, repair the open in the SOL B wire between solenoid wire harness A 8P connector and the PCM. If there is continuity, that section of the circuit is intact, so move to the solenoid internal resistance check.
Check shift solenoid valve B internal resistance
For the next check, disconnect the shift solenoid valve B 2P connector. Measure resistance between shift solenoid valve B connector terminal No. 1 and body ground. The expected reading is again 10.6－13.5 Ω. If the reading is in range, the solenoid is OK, and the repair direction is an open in the SHB+ wire between solenoid wire harness A 8P connector and shift solenoid valve B. If the reading is not in range, shift solenoid valve B is faulty, and the directed repair is to replace the lower valve body.
Verification and takeaway
After the repair or PCM action, verify the repair separately from the circuit testing. Use the same basic check: clear the DTC with the HDS, start the engine in P, wait for at least 10 seconds, and confirm P0977 does not return as pending or confirmed. The takeaway is simple: for P0977, prove the code is active, test the circuit in order, separate an open wire from a solenoid resistance fault, and only move toward PCM action when the circuit checks in range. For more diagnostic training, visit stepdiagnostics.com.
Final check
P0977 is handled as an electrical circuit diagnosis: verify the code, check resistance and continuity in order, then verify the code stays gone.
For more guided automotive diagnostics, visit STEP Diagnostics.
