What this code means
P0977 may indicate that the ICM is seeing a high-condition problem on the shift solenoid valve B control circuit, where the commanded solenoid state and the return signal may not/c
What the vehicle may do
- The vehicle may set a warning light.
- Transmission or drive behavior may feel abnormal.
- The vehicle may limit operation depending on how the fault is handled.
Possible fault areas
- Possible shift solenoid valve B concern.
- Possible SH-B circuit wiring or connector concern.
- Possible ICM concern.
Diagnostic path
Opening context
On this 2020 to 2025 Honda CR-V 2.0 hybrid, P0977 points to the ICM seeing a high-condition problem on the shift solenoid valve B control circuit. In plain terms, the command from the module and the return signal may not be lining up when the module is trying to turn that solenoid off. The vehicle may set a warning light, may have abnormal transmission or drive behavior, or may limit operation depending on the fault. The broad areas in play are the shift solenoid valve B, the SH-B circuit wiring and connectors, and the ICM itself. Before you get into the pinpoint checks, start with the basic troubleshooting approach so you are not chasing this code out of sequence.
Confirm the monitor conditions
Now reproduce the operating conditions for P0977. Turn the vehicle to READY TO DRIVE mode. Then shift the transmission to P position/mode and wait for at least 1 second. Keep this confirmation step separate from the circuit testing; it is the monitor gate that lets the fault logic run.
Understand the fault logic
The ICM sets this code when the return signal does not match the ICM command to turn shift solenoid valve B off. So the diagnosis is checking whether the solenoid side and the SH-B circuit respond the way the module expects. Also, there is no direct method here to test the component by itself, so the troubleshooting is done through the related circuit and component checks.
Shift solenoid valve B response check
For the shift solenoid valve B inspection, disconnect the shift solenoid valve cover assembly connector, the 5P connector. Use the HDS to clear DTCs for the ICM. Then jump terminal No. 4 of that 5P connector to body ground with a jumper wire. After that, run the related confirmation routine. The expected result is that the related code is indicated. If that forced-ground check gives the expected result, the path points to a problem with shift solenoid valve B. If it does not give the expected result, the issue is in other related components, so keep following the circuit path instead of calling the solenoid.
SH-B circuit open-wire check
Next, check the SH-B circuit for an open. Disconnect the shift solenoid valve cover assembly 5P connector again, then disconnect ICM connector P, the 36P connector. Perform the SH-B open-wire inspection in the OFF condition. Normal is less than 1 Ω. If that check is abnormal, the problem is in the circuit.
ICM decision point
If the other inspection items all show normal condition, then the remaining fault path is the ICM. At that point, the diagnosis has moved past the solenoid response check and the SH-B circuit open-wire check, and the problem is determined to be with the ICM.
Takeaway
The clean way through P0977 is to start with the basic checks, confirm the operating conditions, force the solenoid circuit response, check SH-B continuity, and only then make the ICM call if the other checks are normal. Don’t skip ahead, because this code is about whether the commanded state and return signal agree. For more diagnostic training, visit stepdiagnostics.com.
Final check
P0977 diagnosis should stay focused on circuit response and continuity before drawing conclusions about the solenoid or ICM.
For more guided automotive diagnostics, visit STEP Diagnostics.
