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DTC codes / P09xx · Transmission / P0964

P0964Pressure Control Solenoid 'B' Control Circuit/Open

P0964 indicates that the transmission control module (TCM) has detected an open circuit or excessive resistance in the control circuit for pressure control solenoid 'B', which is used to regulate hydraulic pressure inside the automatic transmission. The TCM monitors the solenoid's electrical path and sets this code when the expected current or voltage is outside the normal range, often resulting in degraded shift quality or a default limp mode.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaTransmission

Symptoms you may notice

  • Illumination of the check engine light or transmission warning light
  • Harsh or delayed gear shifts, especially when engaging drive or reverse
  • Transmission stuck in a single gear or limp mode
  • Slipping or flaring during acceleration
  • Often no symptoms besides the warning light, particularly if the fault is intermittent

Common causes, most likely first

  1. Damaged or disconnected wiring harness to the pressure control solenoid 'B'
  2. Corroded or loose electrical connector at the solenoid or TCM
  3. Open winding inside the pressure control solenoid 'B' itself
  4. Faulty transmission control module (TCM) driver circuit
  5. Internal transmission damage causing debris to block solenoid operation
  6. Poor ground connection for the transmission electrical system

How to diagnose and fix it

  1. Scan all modules for stored and pending codes, and record freeze-frame data to understand when the fault occurs
  2. Visually inspect the solenoid 'B' wiring harness and connector for chafing, corrosion, or loose pins
  3. Measure resistance of the solenoid 'B' circuit at the TCM connector and compare to manufacturer specifications
  4. Check for continuity and short-to-ground on the control circuit between the TCM and solenoid
  5. If resistance is out of spec, remove the transmission pan and test the solenoid directly; replace if open
  6. Inspect the TCM connector and pins for damage or corrosion, and repair or replace as needed
  7. Clear codes and perform a road test to verify the repair and ensure no other codes return

What P0964 doesn't always mean

  • A P0964 can be set by a simple loose connector or chafed wire, so always inspect the harness before condemning the solenoid.
  • In some vehicles, a faulty TCM or a poor ground can mimic a solenoid circuit failure, leading to unnecessary solenoid replacement.
  • Intermittent open circuits may only appear when the transmission is hot or during certain driving conditions, so a wiggle test of the harness is essential.
  • The code does not always indicate a mechanical transmission failure; electrical faults are far more common and cheaper to fix.
  • Related codes such as P0962 or P0963 may also be present, indicating a problem with the same solenoid circuit or its power supply.

Can I keep driving with P0964?

It is generally safe to drive with P0964 if the transmission shifts normally, but avoid heavy acceleration or towing until the fault is repaired. If the transmission enters limp mode or shifts harshly, seek service promptly to prevent further damage.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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