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

• P079C — OBD2 code P079C flags a problem with the automatic transmission control (transmission friction element "C" slip detected). Short, gentle driving to a shop is usually possible. Common culprits: internal mechanical wear (clutches, torque converter), valve body wear, failed shift or pressure control solenoid.
• P079D — Transmission Friction Element "D" Slip Detected (P079D): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by valve body wear, failed shift or pressure control solenoid, internal mechanical wear (clutches, torque converter).
• P079E — OBD2 code P079E flags a problem with the automatic transmission control (transmission friction element "E" slip detected). Short, gentle driving to a shop is usually possible. Common culprits: wiring or connector faults in the valve body harness, valve body wear, failed shift or pressure control solenoid.
• P079F — OBD2 code P079F flags a problem with the automatic transmission control (transmission friction element "F" slip detected). Short, gentle driving to a shop is usually possible. Common culprits: wiring or connector faults in the valve body harness, internal mechanical wear (clutches, torque converter), low or degraded transmission fluid.
• P07A0 — Transmission Friction Element "G" Slip Detected (P07A0): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by valve body wear, faulty transmission speed sensor, internal mechanical wear (clutches, torque converter).
• P07A1 — OBD2 code P07A1 flags a problem with the automatic transmission control (transmission friction element "H" slip detected). Short, gentle driving to a shop is usually possible. Common culprits: internal mechanical wear (clutches, torque converter), valve body wear, failed shift or pressure control solenoid.
• P07A2 — OBD2 code P07A2 flags a problem with the automatic transmission control (transmission friction element "A" performance/stuck off). Short, gentle driving to a shop is usually possible. Common culprits: valve body wear, internal mechanical wear (clutches, torque converter), wiring or connector faults in the valve body harness.
• P07A3 — OBD2 code P07A3 flags a problem with the automatic transmission control (transmission friction element "A" stuck on). Short, gentle driving to a shop is usually possible. Common culprits: failed shift or pressure control solenoid, valve body wear, low or degraded transmission fluid.
• P07A4 — P07A4 — Transmission Friction Element "B" Performance/Stuck Off. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: wiring or connector faults in the valve body harness, failed shift or pressure control solenoid, faulty transmission speed sensor.
• P07A5 — Transmission Friction Element "B" Stuck On (P07A5): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by faulty transmission speed sensor, valve body wear, failed shift or pressure control solenoid.
• P07A6 — Transmission Friction Element "C" Performance/Stuck Off (P07A6): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by valve body wear, failed shift or pressure control solenoid, internal mechanical wear (clutches, torque converter).
• P07A7 — OBD2 code P07A7 flags a problem with the automatic transmission control (transmission friction element "C" stuck on). Short, gentle driving to a shop is usually possible. Common culprits: internal mechanical wear (clutches, torque converter), wiring or connector faults in the valve body harness, valve body wear.
• P07A8 — Transmission Friction Element "D" Performance/Stuck Off (P07A8): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by internal mechanical wear (clutches, torque converter), wiring or connector faults in the valve body harness, failed shift or pressure control solenoid.
• P07A9 — OBD2 code P07A9 flags a problem with the automatic transmission control (transmission friction element "D" stuck on). Short, gentle driving to a shop is usually possible. Common culprits: failed shift or pressure control solenoid, wiring or connector faults in the valve body harness, low or degraded transmission fluid.
• P07AA — Transmission Friction Element "E" Performance/Stuck Off (P07AA): 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, low or degraded transmission fluid.
• P07AB — Transmission Friction Element "E" Stuck On (P07AB): 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, internal mechanical wear (clutches, torque converter), wiring or connector faults in the valve body harness.
• P07AC — Transmission Friction Element "F" Performance/Stuck Off (P07AC): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by internal mechanical wear (clutches, torque converter), valve body wear, faulty transmission speed sensor.
• P07AD — Transmission Friction Element "F" Stuck On (P07AD): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by wiring or connector faults in the valve body harness, low or degraded transmission fluid, valve body wear.
• P07AE — OBD2 code P07AE flags a problem with the automatic transmission control (transmission friction element "G" performance/stuck off). Short, gentle driving to a shop is usually possible. Common culprits: faulty transmission speed sensor, low or degraded transmission fluid, valve body wear.
• P07AF — Transmission Friction Element "G" Stuck On (P07AF): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by internal mechanical wear (clutches, torque converter), valve body wear, failed shift or pressure control solenoid.
• P07B0 — OBD2 code P07B0 flags a problem with the automatic transmission control (transmission friction element "H" performance/stuck off). Short, gentle driving to a shop is usually possible. Common culprits: valve body wear, low or degraded transmission fluid, failed shift or pressure control solenoid.
• P07B1 — Transmission Friction Element "H" Stuck On (P07B1): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by wiring or connector faults in the valve body harness, failed shift or pressure control solenoid, faulty transmission speed sensor.
• P07B2 — P07B2 — Transmission Park Position Sensor/Switch "A" Circuit Open. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: wiring or connector faults in the valve body harness, internal mechanical wear (clutches, torque converter), valve body wear.
• P07B3 — P07B3 — Transmission Park Position Sensor/Switch "A" Circuit Low. 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, valve body wear.