P0966: Pressure Control Solenoid B Control Circuit Low — what it means, the affected system and what to check before replacing parts.
Meaning, symptoms, causes and checks
Pressure-control solenoid B command: The electrical input is below its permitted range. This signal-level finding does not by itself establish a mechanical failure. The letter B identifies a control channel, not a universal valve location. An electrical control-circuit result must be distinguished from the valve's hydraulic response.
Affected system: Transmission pressure-control solenoids
Symptoms
- Shift quality may deteriorate when electrical control of pressure-regulating solenoid B is affected.
- Harsh gear engagement or transmission slip may be noticed, but P0966 alone does not demonstrate a hydraulic fault.
Possible causes
- Damaged, broken or shorted wiring in the pressure-control solenoid B circuit.
- Corroded or loose connectors, or an electrical defect in solenoid B itself.
What to check
- Check technical service information applicable to this transmission before dismantling components.
- Inspect the solenoid B wiring and connectors for corrosion, looseness or damage.
- With the circuit isolated as prescribed, test continuity and solenoid resistance against the manufacturer's specification before deciding on replacement.
Also written as: P0966-00, P096600, PO966 (some scan tools add the fault-type byte, e.g. -00).