Shift Solenoid B Control Circuit High
What it means
P0977 means the transmission control module sees high voltage on the control circuit for shift solenoid B, the valve that helps engage specific gears. The result is often missed or harsh shifts and, on many vehicles, limp mode. It usually stems from a failed solenoid, a wiring short, or a bad connector.
Can I keep driving? Drivable but expect harsh shifts or limp mode — get it fixed soon to avoid being stranded in one gear.
Real-world scan data
Appears alongside · share of P0977 scans
Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.
Common symptoms
What you'll notice
- Check-engine light on
- Transmission won't shift into or out of certain gears
- Harsh or delayed shifting
- Limp mode (stuck in one gear)
Common causes
Most likely first
- Faulty shift solenoid BLikely
- Wiring short to power or open in the solenoid control circuitCommon
- Loose or corroded connector at the transmissionCommon
- Failed transmission control module (TCM)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check for related shift-solenoid codes (P0975, P0976).
- Inspect the transmission connector and wiring for damage, corrosion, or a short to voltage.
- Measure shift solenoid B resistance against spec; replace it if out of range.
- Verify fluid level and condition, then clear and re-test. If the circuit is good, have the TCM checked.
FAQ
Quick answers
Is it safe to drive with P0977?+
Can I just clear P0977?+
Related codes
Read & clear P0977 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.