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.

P0783 — OBD2 code P0783 flags a problem with the sensor and actuator circuits (3-4 shift malfunction). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, control module driver fault, corroded, loose or damaged connector.
P0784 — 4-5 Shift Malfunction (P0784): 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 poor ground connection, faulty sensor or actuator of the affected circuit, blown fuse feeding the circuit.
P0785 — OBD2 code P0785 flags a problem with the sensor and actuator circuits (shift timing solenoid a malfunction). The car is usually drivable while you plan the repair. Common culprits: corroded, loose or damaged connector, open or shorted wiring in the circuit, control module driver fault.
P0786 — Shift Timing Solenoid A Range/Performance (P0786): 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 poor ground connection, open or shorted wiring in the circuit, corroded, loose or damaged connector.
P0787 — Shift Timing Solenoid A Low (P0787): 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 poor ground connection, blown fuse feeding the circuit, faulty sensor or actuator of the affected circuit.
P0788 — OBD2 code P0788 flags a problem with the sensor and actuator circuits (shift timing solenoid a high). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, blown fuse feeding the circuit, open or shorted wiring in the circuit.
P0789 — Shift Timing Solenoid A Intermittent (P0789): 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, corroded, loose or damaged connector, control module driver fault.
P078A — P078A — Shift Timing Solenoid B Malfunction. 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, blown fuse feeding the circuit, faulty sensor or actuator of the affected circuit.
P078B — OBD2 code P078B flags a problem with the sensor and actuator circuits (shift timing solenoid b range/performance). The car is usually drivable while you plan the repair. Common culprits: faulty sensor or actuator of the affected circuit, control module driver fault, open or shorted wiring in the circuit.
P078C — P078C — Shift Timing Solenoid B Low. 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, poor ground connection.
P078D — OBD2 code P078D flags a problem with the sensor and actuator circuits (shift timing solenoid b high). The car is usually drivable while you plan the repair. Common culprits: blown fuse feeding the circuit, poor ground connection, open or shorted wiring in the circuit.
P078E — Shift Timing Solenoid B Intermittent (P078E): 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 poor ground connection, control module driver fault, faulty sensor or actuator of the affected circuit.
P0790 — Normal/Performance Switch Circuit Malfunction (P0790): 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 corroded, loose or damaged connector, faulty sensor or actuator of the affected circuit, blown fuse feeding the circuit.
P0791 — OBD2 code P0791 flags a problem with the sensor and actuator circuits (intermediate shaft speed sensor a circuit). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, control module driver fault, corroded, loose or damaged connector.
P0792 — OBD2 code P0792 flags a problem with the sensor and actuator circuits (intermediate shaft speed sensor a circuit range/performance). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, blown fuse feeding the circuit, faulty sensor or actuator of the affected circuit.
P0793 — Intermediate Shaft Speed Sensor A Circuit No Signal (P0793): 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.
P0794 — Intermediate Shaft Speed Sensor A Circuit Intermittent (P0794): 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 corroded, loose or damaged connector, control module driver fault, open or shorted wiring in the circuit.
P0795 — P0795 — Pressure Control Solenoid C Malfunction. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: internal mechanical wear (clutches, torque converter), failed shift or pressure control solenoid, valve body wear.
P0796 — OBD2 code P0796 flags a problem with the automatic transmission control (pressure control solenoid c performance or stuck off). Short, gentle driving to a shop is usually possible. Common culprits: wiring or connector faults in the valve body harness, failed shift or pressure control solenoid, faulty transmission speed sensor.
P0797 — Pressure Control Solenoid C Stuck On (P0797): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by low or degraded transmission fluid, failed shift or pressure control solenoid, valve body wear.
P0798 — OBD2 code P0798 flags a problem with the automatic transmission control (pressure control solenoid c electrical). Short, gentle driving to a shop is usually possible. Common culprits: internal mechanical wear (clutches, torque converter), failed shift or pressure control solenoid, wiring or connector faults in the valve body harness.
P0799 — OBD2 code P0799 flags a problem with the automatic transmission control (pressure control solenoid c intermittent). Short, gentle driving to a shop is usually possible. Common culprits: valve body wear, low or degraded transmission fluid, faulty transmission speed sensor.
P079A — P079A — Transmission Friction Element "A" Slip Detected. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: low or degraded transmission fluid, failed shift or pressure control solenoid, wiring or connector faults in the valve body harness.
P079B — Transmission Friction Element "B" Slip Detected (P079B): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by failed shift or pressure control solenoid, valve body wear, wiring or connector faults in the valve body harness.