P0966
Pressure Control Solenoid B Control Circuit Low
Transmission
Generic OBD-II
Medium
What it means
P0966 means the transmission control module detected low voltage on the control circuit for pressure control solenoid B. That solenoid regulates hydraulic line pressure for shifting, so a fault often shows up as harsh or slipping shifts and can put the transmission into a protective limp mode. Common causes are a failed solenoid or a short in its wiring.
Medium
Can I keep driving? Limited — the transmission may shift harshly or drop into limp mode (fixed gear); drive gently and get it looked at soon to avoid further wear.
Common symptoms
What you'll notice
- Harsh, delayed, or erratic shifting
- Transmission slipping or stuck in one gear (limp mode)
- Check-engine light on
- Reduced acceleration or power
Common causes
Most likely first
- Failed pressure control solenoid BLikely
- Wiring fault in the solenoid circuit (short to ground or open)Common
- Loose or corroded connector at the transmissionCommon
- Low or contaminated transmission fluid affecting solenoid operationLess often
- Faulty transmission control module (TCM)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check transmission fluid level and condition first.
- Inspect the external transmission connector and wiring to solenoid B for shorts, opens, and corrosion.
- Measure solenoid B resistance against spec; replace the solenoid if out of range.
- Repair any damaged wiring or connections, then clear and road-test.
- If the solenoid and wiring are good, have the TCM diagnosed.
FAQ
Quick answers
Is it safe to drive with P0966?+
Only short term. The car may enter limp mode or shift harshly, which is drivable but hard on the transmission — get it repaired soon.
Can I just clear P0966?+
It will come back until the solenoid or its circuit is fixed. Clearing also drops any limp mode only until the fault is detected again.
Related codes
Often seen with P0966
Read & clear P0966 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