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

• P1903 — Transmission 4WD Mode Select Return Input Circuit Failure (P1903): 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, low or degraded transmission fluid.
• P1904 — Transmission Transfer Case Contact Plate Ground Return Open Circuit (P1904): 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, low or degraded transmission fluid, internal mechanical wear (clutches, torque converter).
• P1905 — OBD2 code P1905 flags a problem with the sensor and actuator circuits (OSS circuit intermittent malfunction). The car is usually drivable while you plan the repair. Common culprits: blown fuse feeding the circuit, corroded, loose or damaged connector, open or shorted wiring in the circuit.
• P1906 — TSS Circuit Intermittent Malfunction (P1906): 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, corroded, loose or damaged connector, control module driver fault.
• P1907 — OBD2 code P1907 flags a problem with the automatic transmission control (pressure control solenoid "B" intermittent short). Short, gentle driving to a shop is usually possible. Common culprits: wiring or connector faults in the valve body harness, faulty transmission speed sensor, valve body wear.
• P1909 — Pressure Control Solenoid "C" Open Circuit (P1909): 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).
• P1910 — P1910 — Pressure Control Solenoid "C" Intermittent Short. 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.
• P1911 — OBD2 code P1911 flags a problem with the sensor and actuator circuits (kickdown pull relay open or short circuit to ground). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, corroded, loose or damaged connector, faulty sensor or actuator of the affected circuit.
• P1912 — Kickdown Hold Relay Open or Short Circuit to Ground (P1912): 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 control module driver fault, faulty sensor or actuator of the affected circuit, blown fuse feeding the circuit.
• P1913 — P1913 — Transmission Pressure Circuit Solenoid Open or Short to Ground. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: failed shift or pressure control solenoid, internal mechanical wear (clutches, torque converter), faulty transmission speed sensor.
• P1914 — P1914 — Trans Temp Sensor Circuit Open or Shorted to Pwr or Gnd. 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, blown fuse feeding the circuit, faulty sensor or actuator of the affected circuit.
• P1915 — VFS A Pressure Output Failed Low (P1915): 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, corroded, loose or damaged connector, blown fuse feeding the circuit.
• P1916 — P1916 — VFS B Pressure Output Failed Low. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: control module driver fault, faulty sensor or actuator of the affected circuit, blown fuse feeding the circuit.
• P1917 — VFS C Pressure Output Failed Low (P1917): 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, poor ground connection.
• P1919 — P1919 — Engine Coolant Temperature Signal Fault. P1919 can make engine-temperature information unreliable.
• P1920 — P1920 — Engine Speed Signal Circuit Malfunction. P1920 indicates that engine-speed information may be missing or inconsistent.
• P1921 — P1921 — Gear Shift Lever Position Signal Fault. Avoid driving if the P1921 code is active and the gear indicator does not match the lever, a selected gear will not engage, or shifts are abrupt.
• P1922 — P1922 — Fuel Additive Level Circuit Fault. P1922 alone normally does not create an immediate driving hazard.
• P1923 — P1923 — Fuel Additive Level Signal Out of Range. P1923 usually does not require immediate stopping, but the additive system may not provide reliable protection.
• P1924 — P1924 — Low Fuel Additive Sensor Voltage. P1924 is generally a caution-level electrical fault rather than an immediate stop condition, but the fuel additive level reading may be unreliable.
• P1925 — P1925 — Fuel Additive Level Supply Overvoltage. P1925 is not normally an immediate engine-stopping fault, but the excessive supply voltage can corrupt the additive-level input and prevent proper dosing.
• P1926 — P1926 — Intermittent Fuel Additive Level Circuit Fault. P1926 is an intermittent fuel-additive level-circuit fault and is not, by itself, proof of major engine failure.
• P1927 — P1927 — Fuel Additive Level Too Low or Empty. Driving may be possible if P1927 is the only warning, but an empty additive reservoir can restrict regeneration or aftertreatment operation on applicable vehicles.
• P1928 — P1928 — Fuel Additive Pump Circuit Open. P1928 generally permits driving to a repair shop, but the fuel-additive system may not function correctly.