OBD2 Fault Code Library

Free lookup for thousands of OBD2 trouble codes: filter by family, read short meanings, and open deeper articles. Desktop ELM327 scanner with live data and AI guidance.

OBD2 symptoms

Look up diagnostic trouble codes by what the car is doing: misfire, overheating, rough idle, a check engine light, and other common symptoms.

• Engine misfire
• Engine overheating
• Rough idle
• Check engine light
• Poor fuel economy
• Hard starting
• Engine stalling
• Catalytic converter efficiency
• Oxygen sensor fault
• EVAP leak
• Thermostat not reaching temperature
• Lean air-fuel mixture
• Rich air-fuel mixture
• EGR flow fault
• Engine knock
• Charging system
• Throttle position
• Mass airflow sensor
• Turbo underboost
• Coolant temperature sensor
• Transmission fault

• P0943 — P0943 — Hydraulic Pressure Unit Cycling Period Too Short. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: corroded, loose or damaged connector, faulty sensor or actuator of the affected circuit, control module driver fault.
• P0944 — Hydraulic Pressure Unit Loss of Pressure (P0944): a powertrain (engine/transmission) fault affecting the sensor and actuator circuits. The car is usually drivable while you plan the repair. Most often caused by faulty sensor or actuator of the affected circuit, open or shorted wiring in the circuit, control module driver fault.
• P0945 — Hydraulic Pump Relay Circuit/Open (P0945): a powertrain (engine/transmission) fault affecting the sensor and actuator circuits. The car is usually drivable while you plan the repair. Most often caused by blown fuse feeding the circuit, control module driver fault, corroded, loose or damaged connector.
• P0946 — Hydraulic Pump Relay Circuit Range/Performance (P0946): a powertrain (engine/transmission) fault affecting the sensor and actuator circuits. The car is usually drivable while you plan the repair. Most often caused by blown fuse feeding the circuit, poor ground connection, corroded, loose or damaged connector.
• P0947 — P0947 — Hydraulic Pump Relay Circuit Low. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: open or shorted wiring in the circuit, poor ground connection, blown fuse feeding the circuit.
• P0948 — OBD2 code P0948 flags a problem with the sensor and actuator circuits (hydraulic pump relay circuit high). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, blown fuse feeding the circuit, poor ground connection.
• P0949 — P0949 — Auto Shift Manual Adaptive Learning Not Complete. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: poor ground connection, control module driver fault, open or shorted wiring in the circuit.
• P0950 — Auto Shift Manual Control Circuit (P0950): a powertrain (engine/transmission) fault affecting the sensor and actuator circuits. The car is usually drivable while you plan the repair. Most often caused by open or shorted wiring in the circuit, blown fuse feeding the circuit, faulty sensor or actuator of the affected circuit.
• P0951 — Auto Shift Manual Control Circuit Range/Performance (P0951): a powertrain (engine/transmission) fault affecting the sensor and actuator circuits. The car is usually drivable while you plan the repair. Most often caused by blown fuse feeding the circuit, open or shorted wiring in the circuit, faulty sensor or actuator of the affected circuit.
• P0952 — P0952 — Auto Shift Manual Control Circuit Low. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: poor ground connection, corroded, loose or damaged connector, open or shorted wiring in the circuit.
• P0953 — OBD2 code P0953 flags a problem with the sensor and actuator circuits (auto shift manual control circuit high). The car is usually drivable while you plan the repair. Common culprits: faulty sensor or actuator of the affected circuit, control module driver fault, poor ground connection.
• P0954 — P0954 — Auto Shift Manual Control Circuit Intermittent. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: blown fuse feeding the circuit, control module driver fault, open or shorted wiring in the circuit.
• P0955 — P0955 — Auto Shift Manual Mode Circuit. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: blown fuse feeding the circuit, faulty sensor or actuator of the affected circuit, control module driver fault.
• P0956 — P0956 — Auto Shift Manual Mode Circuit Range/Performance. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: control module driver fault, poor ground connection, blown fuse feeding the circuit.
• P0957 — P0957 — Auto Shift Manual Mode Circuit Low. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: corroded, loose or damaged connector, control module driver fault, blown fuse feeding the circuit.
• P0958 — OBD2 code P0958 flags a problem with the sensor and actuator circuits (auto shift manual mode circuit high). The car is usually drivable while you plan the repair. Common culprits: blown fuse feeding the circuit, faulty sensor or actuator of the affected circuit, corroded, loose or damaged connector.
• P0959 — OBD2 code P0959 flags a problem with the sensor and actuator circuits (auto shift manual mode circuit intermittent). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, blown fuse feeding the circuit, corroded, loose or damaged connector.
• P0960 — OBD2 code P0960 flags a problem with the automatic transmission control (pressure control solenoid "A" control circuit/open). Short, gentle driving to a shop is usually possible. Common culprits: wiring or connector faults in the valve body harness, valve body wear, faulty transmission speed sensor.
• P0961 — P0961 — Pressure Control Solenoid "A" Control Circuit Range/Performance. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: valve body wear, wiring or connector faults in the valve body harness, low or degraded transmission fluid.
• P0962 — OBD2 code P0962 flags a problem with the automatic transmission control (pressure control solenoid "A" control circuit low). Short, gentle driving to a shop is usually possible. Common culprits: low or degraded transmission fluid, faulty transmission speed sensor, internal mechanical wear (clutches, torque converter).
• P0963 — P0963 — Pressure Control Solenoid "A" Control Circuit High. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: internal mechanical wear (clutches, torque converter), wiring or connector faults in the valve body harness, valve body wear.
• P0964 — P0964 — Pressure Control Solenoid "B" Control Circuit/Open. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: valve body wear, wiring or connector faults in the valve body harness, failed shift or pressure control solenoid.
• P0965 — P0965 — Pressure Control Solenoid "B" Control Circuit Range/Performance. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: internal mechanical wear (clutches, torque converter), valve body wear, failed shift or pressure control solenoid.
• P0966 — P0966 — Pressure Control Solenoid "B" Control Circuit Low. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: faulty transmission speed sensor, failed shift or pressure control solenoid, internal mechanical wear (clutches, torque converter).