Pressure Control Solenoid "A" Control Circuit/Open
Diagnostic trouble code P0960 indicates that the powertrain control module (PCM) or transmission control module (TCM) has detected an open circuit in the control circuit for pressure control solenoid 'A'. The module sets this code when the voltage or resistance in the solenoid 'A' circuit falls outside of the expected manufacturer specifications, preventing proper hydraulic pressure regulation in the transmission.
This code is considered high severity because improper transmission line pressure can lead to severe internal transmission damage, slipping, or a complete loss of driveability. It should be diagnosed and repaired immediately to prevent costly transmission failure.
Common symptoms
- Illuminated Check Engine Light
- Harsh or erratic transmission shifting
- Transmission slipping between gears
- Transmission stuck in a default or 'limp' mode
- Decreased fuel economy
Likely causes
- Damaged, broken, or corroded wiring in the pressure control solenoid 'A' circuit
- Loose or corroded electrical connectors at the transmission or TCM
- Failed or defective pressure control solenoid 'A'
- Low or dirty transmission fluid causing poor electrical connection or solenoid failure
- Internal transmission wiring harness failure
- Faulty Transmission Control Module (TCM) or Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Check the transmission fluid level and condition.
Look for: Fluid that is significantly low, burnt, or heavily contaminated with metal debris indicates internal transmission issues that may have caused the solenoid failure or circuit issue.
Visually inspect the wiring harness and connectors for the transmission and TCM.
Look for: Look for frayed wires, melted insulation, backed-out pins, or corrosion in the connectors that would cause an open circuit.
Test the resistance of pressure control solenoid 'A' using a digital multimeter.
Look for: Compare the measured resistance to the manufacturer's specification. An infinite reading (OL) indicates an internal open in the solenoid, requiring replacement.
Perform a continuity test on the wiring between the TCM and the transmission connector.
Look for: High resistance or a lack of continuity (OL) on the control or ground wire indicates a break in the wiring harness that needs to be repaired.
Check for voltage and ground signals from the TCM to the solenoid while commanding the solenoid on with a scan tool.
Look for: If the wiring is intact but the TCM fails to provide the correct voltage or ground signal when commanded, the TCM may be faulty or require reprogramming.
This page explains the generic P0960 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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