Shift solenoids are small plungers that the ECU activates by sending an electrical current through a coil of wire that is wrapped around the plunger mechanism. If the computer detects an unusually low voltage along the shift solenoid B control circuit, it will save a P0976 DTC.
How Serious is the Code?
The P0976 diagnostic trouble code gets triggered when there is a control issue with one of the shift solenoids. This will result in serious drivability issues that will go from barely noticeable to a nonfunctional transmission. So this is a very serious OBD2 code.
Symptoms of a P0976 include:
- Harsh gear changes
- Transmission may not shift into gear
- Dirty transmission fluid
- Low transmission fluid
- Damaged connectors and/or wiring
- Bad shift solenoid
How to Diagnose the Code?
Diagnosing a P0976 OBDII trouble code, should start with an examination of the transmission fluid. Low levels and excessive dirt/thinning fluid can cause the shift solenoid to malfunction. If there are no issues with the transmission fluid, the wiring and connectors along the transmission wiring harness will need to be examined. If no shorted wires or broken/corroded connectors are found, then the shift solenoid itself will have to be checked.
What Repairs Will Fix P0976?
- Service the transmission
- Replace or repair damage wiring/connectors
- Replace shift solenoid
- P0975 – Shift Solenoid “B” Control Circuit Range/Performance
- P0977 – Shift Solenoid “B” Control Circuit High