P0977
Shift Solenoid B Control Circuit High
Transmission
Generic OBD-II
Medium
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.
Medium
Can I keep driving? Drivable but expect harsh shifts or limp mode — get it fixed soon to avoid being stranded in one gear.
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?+
For short trips, but the transmission may be stuck in a gear or shift harshly. Prolonged driving in limp mode isn't ideal, so repair it promptly.
Can I just clear P0977?+
It returns until the solenoid or wiring is repaired. Clearing only lifts limp mode briefly.
Related codes
Often seen with P0977
Read & clear P0977 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX