AutoLogicTools code library
OBD-II Trouble Codes
Look up OBD-II trouble codes with plain-English explanations, common causes, symptoms, diagnostic steps, repair cost ranges, and links to the AutoLogicTools Repair Cost Estimator. Coverage is growing — start with P0420.
Powertrain (P codes)
97 codes published.
'A' Camshaft Position Actuator Circuit (Bank 1)
The intake camshaft position actuator on bank 1 has an electrical fault — the PCM is either not seeing the response it expects from the VVT solenoid, or the circuit itself is open or shorted. Almost always an oil-related issue at the root.
Read this codeCamshaft Position A — Timing Over-Advanced or System Performance (Bank 1)
The intake camshaft on Bank 1 is more advanced than the engine computer commanded. Most often caused by a stuck variable valve timing (VVT) solenoid or dirty engine oil. Address promptly — neglected timing issues can damage the engine.
Read this code'B' Camshaft Position Actuator Circuit (Bank 1)
The exhaust camshaft position actuator on bank 1 has an electrical fault. The PCM is sending a command to the exhaust VVT solenoid and not seeing the electrical response it expects — usually because of oil contamination, a failed solenoid, or wiring damage.
Read this codeCamshaft Position B — Timing Over-Advanced or System Performance (Bank 1)
The exhaust camshaft on Bank 1 is more advanced than the engine computer commanded. Most often caused by a stuck VVT solenoid on the exhaust cam, dirty engine oil, or a stretched timing chain on high-mileage engines.
Read this codeCrankshaft Position — Camshaft Position Correlation (Bank 1, Sensor A)
The relationship between the crankshaft and intake camshaft on Bank 1 is outside the expected window. Often a stretched timing chain — known issue on Hyundai/Kia 2.4L Theta II, BMW N20/N26, Audi 2.0T, and other timing-chain engines. Don't ignore it.
Read this codeCrankshaft Position — Camshaft Position Correlation (Bank 1, Sensor B)
The relationship between the crankshaft and exhaust camshaft on Bank 1 is outside the expected window. Same root causes as P0016 — often a stretched timing chain. Don't ignore it.
Read this codeCrankshaft Position - Camshaft Position Correlation (Bank 2 Sensor A)
The PCM compared the crankshaft position to the bank-2 intake camshaft position and found them out of sync beyond what variable valve timing should produce. Usually means the timing chain on bank 2 has stretched, the phaser is mechanically off, or the cam sensor is reading incorrectly.
Read this codeCrankshaft Position - Camshaft Position Correlation (Bank 2 Sensor B)
The PCM compared the crankshaft position to the bank-2 exhaust camshaft position and found them out of sync beyond the VVT operating range. Almost always a mechanical timing problem — chain stretch, worn phaser, or a failing exhaust cam sensor on bank 2.
Read this code'A' Camshaft Position Actuator Circuit (Bank 2)
The PCM is commanding the intake-camshaft VVT solenoid on bank 2, but the electrical feedback it's getting back doesn't match what it expects — usually an open, short, or wiring fault in the solenoid circuit on the bank-2 side of the engine.
Read this code'A' Camshaft Position Timing Over-Advanced or System Performance (Bank 2)
The intake camshaft on bank 2 isn't holding the timing position the PCM commanded — it's reading further advanced than expected. The electrical side of the VVT solenoid is fine; the camshaft itself isn't responding the way it should.
Read this code'B' Camshaft Position Actuator Circuit (Bank 2)
The PCM detected an electrical fault in the exhaust-camshaft VVT solenoid circuit on bank 2. 'B' designates the exhaust cam — the one that controls when the exhaust valves open relative to crankshaft position.
Read this code'B' Camshaft Position Timing Over-Advanced or System Performance (Bank 2)
The exhaust camshaft on bank 2 is sitting further advanced than the PCM commanded — the solenoid is responding electrically, but the cam itself isn't tracking the commanded position. Usually oil, phaser, or chain related.
Read this codeFuel Rail/System Pressure Too Low
The fuel pressure at the rail is sitting below what the PCM is commanding under load. On direct-injection engines, this almost always points at the high-pressure fuel pump (HPFP) — not a sensor and usually not the low-pressure pump in the tank.
Read this codeFuel Rail/System Pressure Too High
The opposite of P0087. Rail pressure is sitting above what the PCM is commanding, which usually means the system can't bleed pressure off — most often a stuck or stuck-closed fuel pressure regulator on a direct-injection engine.
Read this codeFuel Pressure Regulator 1 Performance
The fuel pressure regulator isn't doing what it's been told to do — pressure isn't responding to command changes the way the PCM expects. Different from P0087/P0088 because this one flags the regulator specifically, not the rail pressure outcome.
Read this codeMass Air Flow Sensor Range/Performance Problem
The engine computer detected that the mass airflow (MAF) sensor reading doesn't match expected values based on throttle position and engine speed. Most often caused by a dirty MAF sensor — cleaning resolves a large share of cases.
Read this codeMass Air Flow Sensor Circuit Low Input
The engine computer detected that the mass airflow (MAF) sensor signal is reading too low — often because the sensor is disconnected, the wiring is damaged, or the sensor itself has failed. The engine may run rough or stall.
Read this codeMass or Volume Air Flow Circuit High Input
The mass airflow (MAF) sensor is reporting more airflow than the PCM thinks is physically possible. Two main causes: unmetered air sneaking into the engine after the sensor, or a contaminated sensor over-reporting.
Read this codeIntake Air Temperature Sensor Circuit High Input
The intake air temperature (IAT) sensor signal is reading higher than the PCM's normal operating range, usually pointing to an open circuit, a failed sensor, or a wiring problem.
Read this codeEngine Coolant Temperature Sensor Circuit Low Input
The engine coolant temperature (ECT) sensor signal is reading lower than the PCM expects — usually a short to ground in the circuit or a failed sensor pretending the engine is unrealistically hot.
Read this codeEngine Coolant Temperature Sensor Circuit High Input
The ECT sensor signal is reading higher than the PCM expects — usually an open circuit, a broken sensor, or a disconnected connector that makes the engine appear permanently cold.
Read this codeThrottle/Pedal Position Sensor 'A' Circuit Range/Performance
The throttle position sensor is reporting a value that's electrically valid but doesn't line up with what the PCM expects based on pedal input, RPM, and airflow. On most electronic throttle vehicles, this is a contaminated throttle body or a tired TPS — not always the actuator motor itself.
Read this codeThrottle/Pedal Position Sensor 'A' Circuit Low Input
The throttle position sensor signal is pegged near zero volts no matter where the pedal is. This is an electrical fault — usually an open ground, broken signal wire, or shorted-internal sensor — not a contamination issue like P0121.
Read this codeThrottle/Pedal Position Sensor 'A' Circuit High Input
The throttle position sensor signal is pegged near the 5V reference voltage no matter where the pedal is. Mirror of P0122 — usually a short to reference voltage, an open ground at the sensor, or a failed-internal-shorted sensor.
Read this codeCoolant Temperature Below Thermostat Regulating Temperature
The engine isn't reaching its normal operating temperature in the expected amount of time. The most common cause is a stuck-open thermostat. The car is drivable, but fuel economy and emissions will suffer.
Read this codeO2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
The upstream oxygen sensor on Bank 1 is reporting a voltage that's too low for too long. The sensor may be reading stuck-lean, the wiring may be shorted to ground, or an exhaust leak may be letting in extra air.
Read this codeO2 Sensor Circuit High Voltage (Bank 1, Sensor 1)
The upstream oxygen sensor on Bank 1 is reporting a voltage that's too high for too long. The sensor may be reading stuck-rich, the wiring may be shorted to power, or the engine may actually be running rich.
Read this codeO2 Sensor Circuit Slow Response (Bank 1, Sensor 1)
The upstream oxygen sensor on Bank 1 is responding too slowly when the air-fuel ratio changes. Almost always caused by an aging sensor that has lost the ability to switch quickly. Replacement resolves nearly all P0133 cases.
Read this codeO2 Sensor Circuit No Activity Detected (Bank 1, Sensor 1)
The upstream oxygen sensor on Bank 1 isn't switching at all — the signal is flatlined. Often caused by a disconnected sensor, broken wire, or a failed heater that prevents the sensor from reaching operating temperature.
Read this codeO2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
The internal heater for the Bank 1 upstream oxygen sensor failed. The sensor still works once exhaust heat brings it up to temperature, but it takes longer — meaning slower closed-loop operation and worse cold-start emissions.
Read this codeO2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)
The downstream oxygen sensor on bank 1 is reading a persistently low voltage — well below where a working post-catalyst sensor should sit. Either the sensor itself is failing, the wiring is shorted to ground, or the catalyst has changed how exhaust flows past the sensor.
Read this codeO2 Sensor Circuit No Activity Detected (Bank 1, Sensor 2)
The downstream oxygen sensor on bank 1 isn't producing a signal at all — the voltage is flat, stuck at a single value, or the PCM sees no response when it would expect one. Different failure mode from P0136 (low voltage): no signal, not a low one.
Read this codeO2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)
The internal heater for the Bank 1 downstream oxygen sensor failed. The sensor monitors catalyst efficiency rather than fuel trim, so driveability is unaffected — but the code prevents emissions test compliance.
Read this codeO2 Sensor Circuit Low Voltage (Bank 2, Sensor 1)
The upstream oxygen sensor on bank 2 is reporting a voltage stuck near zero — meaning either the sensor sees a constantly lean mixture, the sensor itself has failed, or there's a wiring break between the sensor and the PCM.
Read this codeO2 Sensor Circuit High Voltage (Bank 2, Sensor 1)
The bank 2 upstream oxygen sensor is reporting voltage stuck high — usually around or above 0.9V — which means the sensor is seeing a rich exhaust mixture, has been contaminated, or has been short-circuited to a voltage source. Different problem set from P0151, even though they sit on the same connector.
Read this codeO2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 1)
The internal heater in the upstream oxygen sensor on bank 2 isn't drawing the current the PCM expects. Either the heater element has failed, the supply or ground wire is broken, or the PCM driver isn't switching the circuit on.
Read this codeO2 Sensor Circuit Low Voltage (Bank 2, Sensor 2)
The downstream oxygen sensor on bank 2 is reading a persistently low voltage. Same fault pattern as P0136, but on the cylinder bank that does not contain cylinder 1 — and the labor estimate often runs higher because of access.
Read this codeO2 Sensor Circuit No Activity Detected (Bank 2, Sensor 2)
The downstream oxygen sensor on bank 2 isn't producing any signal — the voltage is flat or stuck at a single value. Same failure mode as P0140, but on the cylinder bank that does not contain cylinder 1, with the same bank-2 labor premium.
Read this codeO2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 2)
The heater inside the downstream oxygen sensor on bank 2 isn't drawing the current the PCM expects. The sensor itself may produce a signal, but the heater that brings it to operating temperature has failed or has a wiring issue.
Read this codeSystem Too Lean (Bank 1)
The engine computer detected that Bank 1 is running with too much air or too little fuel. The check engine light is on and you may notice rough idling or hesitation, but the car is usually still drivable.
Read this codeSystem Too Rich (Bank 1)
The engine computer detected that Bank 1 is running with too much fuel or too little air. The check engine light is on; you may see black exhaust smoke, smell fuel, and notice rough idling or poor fuel economy.
Read this codeSystem Too Lean (Bank 2)
The engine computer detected that Bank 2 is running with too much air or too little fuel. Same condition as P0171, but on the opposite side of a V-configured engine. Only applies to V engines.
Read this codeSystem Too Rich (Bank 2)
The engine computer detected that Bank 2 is running with too much fuel or too little air. Same condition as P0172, but on the opposite side of a V-configured engine. Only applies to V engines.
Read this codeFuel Rail Pressure Sensor Circuit
A general circuit fault on the fuel rail pressure (FRP) sensor — the PCM can't get a reliable reading from the sensor. This is a sensor/electrical code, not a 'pressure is wrong' code like P0087 or P0088.
Read this codeFuel Rail Pressure Sensor Range/Performance
The fuel rail pressure (FRP) sensor's reading is plausible on its face — not pegged high or low — but it's drifting away from what the PCM expects based on other inputs. This is the 'something's off' code in the FRP sensor family.
Read this codeFuel Rail Pressure Sensor Circuit High Input
The fuel rail pressure sensor's signal is pegged at the top of its range — usually a short to reference voltage or an open ground. This is the electrical mirror of P0192 (which sets when the signal pegs low) and a very different diagnosis from a real over-pressure condition (P0088).
Read this codeTurbocharger/Supercharger Overboost Condition
Boost pressure climbed higher than the PCM commanded and didn't come back down. On modern turbocharged engines, this is almost always a wastegate that won't open — not a damaged turbo, despite how it sounds.
Read this codeTurbocharger/Supercharger Underboost Condition
The PCM commanded boost, but the turbo can't deliver it. On Ford EcoBoost and VW/Audi TSI engines, this is one of the most-searched codes — and the cause is usually a boost leak somewhere in the charge piping or a tired wastegate actuator, not a dead turbo.
Read this codeRandom/Multiple Cylinder Misfire Detected
The engine computer detected misfires across multiple cylinders or random cylinders it can't isolate. The check engine light may be flashing, the engine may run rough, and continued driving can damage the catalytic converter.
Read this codeCylinder 1 Misfire Detected
The engine computer detected a misfire specifically in cylinder 1. Diagnosis is more targeted than P0300 — the bad part is on or feeding cylinder 1. The check engine light may be flashing; pull over if it is.
Read this codeCylinder 2 Misfire Detected
The engine computer detected a misfire specifically in cylinder 2. Diagnosis is more targeted than P0300 — the bad part is on or feeding cylinder 2. The check engine light may be flashing; pull over if it is.
Read this codeCylinder 3 Misfire Detected
The engine computer detected a misfire specifically in cylinder 3. Diagnosis is more targeted than P0300 — the bad part is on or feeding cylinder 3. The check engine light may be flashing; pull over if it is.
Read this codeCylinder 4 Misfire Detected
The engine computer detected a misfire specifically in cylinder 4. On a 4-cylinder engine, this is the last cylinder; on V engines, position varies by manufacturer. The check engine light may be flashing; pull over if it is.
Read this codeCylinder 5 Misfire Detected
The engine computer detected a misfire specifically in cylinder 5. This code only applies to engines with six or more cylinders. Diagnosis is more targeted than P0300 — the bad part is on or feeding cylinder 5.
Read this codeCylinder 6 Misfire Detected
The engine computer detected a misfire specifically in cylinder 6. This code only applies to engines with six or more cylinders. Diagnosis is more targeted than P0300 — the bad part is on or feeding cylinder 6.
Read this codeCylinder 7 Misfire Detected
Cylinder 7 is failing to fire cleanly on a measurable share of combustion events. Because only V8 (and a handful of V10/V12) engines have a cylinder 7, this code points you directly at a specific coil, plug, or injector on a known side of the engine.
Read this codeCylinder 8 Misfire Detected
Cylinder 8 — the last cylinder in the firing order on a V8 — is missing combustion events. The diagnosis is cylinder-specific, but cylinder 8 sits at the far back of a bank on most V8 platforms, which has real consequences for what the repair actually costs.
Read this codeMisfire Detected on Startup (First 1,000 Revolutions)
The PCM detected misfire activity during the first 1,000 revolutions after engine start — short enough that no single cylinder code set, but consistent enough to flag the startup window itself as a problem.
Read this codeKnock Sensor 1 Circuit (Bank 1 or Single Sensor)
The engine computer detected an electrical fault with the knock sensor. Without knock detection, the ECM pulls back ignition timing as a safety measure, which reduces power and hurts fuel economy. The engine still runs, but not at its best.
Read this codeCrankshaft Position Sensor "A" Circuit
The engine computer isn't getting a usable signal from the crankshaft position sensor. The engine may not start, may stall while driving, or may run intermittently — the crank sensor is critical for ignition and fuel injection timing.
Read this codeCamshaft Position Sensor "A" Circuit (Bank 1 or Single Sensor)
The engine computer detected a circuit fault with the camshaft position sensor. The engine may hard-start, run rough, or refuse to start — the cam sensor tells the ECM which stroke each cylinder is on for fuel injection timing.
Read this codeCamshaft Position Sensor "A" Circuit Range/Performance
The camshaft position sensor is producing a signal, but it's not matching what the engine computer expects based on engine speed and crankshaft position. Often points to a stretched timing chain or a worn sensor.
Read this codeEGR Insufficient Flow Detected
The engine computer commanded the exhaust gas recirculation (EGR) valve to open, but the resulting flow was lower than expected. Almost always caused by carbon buildup clogging the EGR passages or a stuck-closed EGR valve.
Read this codeSecondary Air Injection System Incorrect Flow Detected
The secondary air injection system (which briefly pumps fresh air into the exhaust during cold start to help warm up the catalyst) is not flowing the expected amount of air. Common on European cars and certain GM models — and often expensive to fix.
Read this codeCatalyst System Efficiency Below Threshold (Bank 1)
The engine computer detected that the catalytic converter on Bank 1 is not reducing emissions as efficiently as expected. The check engine light is on, but the car is usually still drivable.
Read this codeWarm Up Catalyst Efficiency Below Threshold (Bank 1)
The warm-up catalyst on bank 1 — the small cat mounted close to the engine for fast cold-start emissions control — isn't converting pollutants efficiently anymore. Bank 1 contains cylinder 1, so on most American engines this is the driver-side cat.
Read this codeCatalyst System Efficiency Below Threshold (Bank 2)
The engine computer detected that the catalytic converter on Bank 2 is not reducing emissions as efficiently as expected. Same condition as P0420, but for the opposite side of a V-configured engine. The check engine light is on, but the car is usually still drivable.
Read this codeWarm Up Catalyst Efficiency Below Threshold (Bank 2)
The warm-up catalyst on bank 2 — the smaller cat mounted close to the engine for fast light-off during cold starts — isn't reducing emissions efficiently enough. Different from the main cat code (P0420/P0430) in location and failure pattern.
Read this codeCatalyst System Efficiency Below Threshold (Bank 2)
The main catalytic converter on bank 2 has lost enough efficiency that the PCM no longer trusts it to handle the emissions load. Same problem as the widely-searched P0420, just on the opposite side of the engine.
Read this codeEvaporative Emission Control System Malfunction
A general code indicating a problem with the evaporative emission (EVAP) system. Most often a loose gas cap, a cracked hose, or a faulty purge or vent valve. The car drives normally but will fail an emissions test.
Read this codeEVAP System Incorrect Purge Flow
The EVAP purge system is moving fuel vapor at the wrong rate — too much, too little, or at the wrong time relative to what the PCM commanded. Different from the 'leak' codes (P0440, P0455, P0456) — this one is about flow direction and quantity, not whether the system holds pressure.
Read this codeEvaporative Emission System — Small Leak Detected
The engine computer detected a small leak in the evaporative emission (EVAP) system. The check engine light is on but the car runs normally. The most common cause is a worn gas cap or a small crack in an EVAP hose.
Read this codeEvaporative Emission System Vent Control Circuit Malfunction
The vent valve in the evaporative emission (EVAP) system has an electrical or mechanical fault. Often caused by a failed vent solenoid or by debris and spider webs clogging the vent — both inexpensive fixes.
Read this codeEVAP Vent Solenoid Control Circuit Malfunction
An electrical fault in the circuit that controls the EVAP vent solenoid — the valve that seals the system closed during leak testing. Different from P0446, which is a performance fault; P0449 is specifically about the wiring or solenoid windings.
Read this codeEvaporative Emission System — Large Leak Detected
The engine computer detected a large leak in the evaporative emission (EVAP) system. The most common cause is a loose, missing, or damaged gas cap. The car runs normally but will fail an emissions test until the leak is fixed.
Read this codeEVAP System Very Small Leak Detected
The EVAP system has a leak roughly 0.020 inches in diameter — about half the size of P0455's threshold. About 50% of these codes turn out to be the gas cap. The rest can be frustrating to find because the leak is tiny.
Read this codeEvaporative Emission System Leak Detected (Fuel Cap Loose/Off)
The engine computer detected an EVAP leak and specifically identified the fuel cap as the suspected location. Almost always solved by tightening or replacing the gas cap — the cheapest fix in the EVAP family.
Read this codeCooling Fan Relay 1 Control Circuit
The PCM has detected an electrical fault in the control circuit for the primary cooling fan relay — usually a failed relay, damaged wiring, or a problem with the fan motor itself.
Read this codeEvaporative Emission System Flow During Non-Purge Condition
The EVAP system is showing fuel vapor flow when the PCM hasn't commanded the purge valve open — almost always a stuck-open or leaking purge valve letting vapor pass into the engine continuously instead of only during scheduled purge events.
Read this codeIdle Air Control System Malfunction
The idle air control (IAC) valve isn't responding to PCM commands the way it should — idle is rough, hunting, stalling, or running too high. Applies to older pre-electronic-throttle vehicles where a dedicated IAC valve controls idle airflow around a mechanically-cabled throttle.
Read this codeIdle Air Control System RPM Lower Than Expected
The engine is idling slower than the PCM's target RPM and the idle control strategy can't bring it back up — usually a dirty throttle body, a tired idle air control valve, or a vacuum-related restriction.
Read this codeIdle Air Control System RPM Higher Than Expected
The engine is idling faster than the PCM's target RPM and the idle control strategy can't bring it back down — most often a vacuum leak letting extra air past the throttle plate.
Read this codeSystem Voltage Low
The PCM is seeing battery voltage below the threshold needed for normal operation — usually a failing alternator, an aging battery, or a poor connection on the main charging circuit.
Read this codeSystem Voltage High
The PCM is seeing battery voltage above the maximum safe operating range — almost always a failed voltage regulator inside the alternator pushing too much charge into the system.
Read this codePCM Processor Fault
The powertrain control module has detected an internal processor or memory fault — the computer that runs your engine has flagged a problem with itself. Rare across most platforms, but unusually common on certain Ford EcoBoost and Chrysler V6 engines where the cause is often a known PCM hardware defect.
Read this codeTransmission Control System Malfunction
An umbrella code indicating the transmission control module has detected a fault. The transmission may be in limp mode. Drive directly to a repair shop — the underlying transmission code (often P0741 or a P0750-series code) is what tells the real story.
Read this codeOutput Speed Sensor Circuit Malfunction
The transmission's output speed sensor is reporting an erratic, missing, or impossible signal. This is the sensor the transmission control module uses to know how fast the output shaft is spinning — without it, the TCM can't shift correctly or know what gear to be in.
Read this codeTorque Converter Clutch Circuit Performance / Stuck Off
The torque converter clutch isn't locking up when the PCM commands it to — usually a worn TCC solenoid, dirty transmission fluid, or internal wear inside the converter itself.
Read this codeShift Solenoid A Malfunction
An electrical or hydraulic fault has been detected in shift solenoid A, the solenoid that controls one of the lower gear shifts on most automatic transmissions.
Read this codePost Catalyst Fuel Trim System Too Lean (Bank 1)
The downstream oxygen sensor on bank 1 is reporting a persistently lean signal that the PCM can't correct for, even after the upstream fuel trim has done its work. This points at exhaust leaks, sensor problems, or a cat that's letting unburned oxygen pass through.
Read this codePost Catalyst Fuel Trim System Too Rich (Bank 1)
The bank 1 downstream oxygen sensor is reporting a persistently rich signal that the PCM can't correct out. Usually means a contaminated downstream sensor, a cat that's saturated and dumping unburned fuel through, or fuel system issues that don't trip the upstream lean/rich codes.
Read this codePost Catalyst Fuel Trim System Too Lean (Bank 2)
The downstream oxygen sensor on bank 2 is reporting a persistently lean signal. Mechanically identical to P2096 — same diagnosis, same costs — but you're chasing it on the side of the engine that does NOT contain cylinder 1. Bank identification is the first step.
Read this codePost Catalyst Fuel Trim System Too Rich (Bank 2)
The downstream O2 sensor on bank 2 is reporting a persistently rich signal. Same playbook as P2097 — contaminated sensor, leaking injector, stuck EVAP, or fuel pressure issue — but on the side of the engine that doesn't contain cylinder 1.
Read this codeThrottle/Pedal Position Sensor 'D' Circuit Low Input
One of the two sensors inside the accelerator pedal assembly is reporting near-zero voltage no matter where the pedal is. Different from P0122 — this code is about the pedal side of the drive-by-wire system, not the throttle body.
Read this codeThrottle/Pedal Position Sensor 'E' Circuit Low Input
The 'E' position sensor inside the accelerator pedal assembly — the second of the two redundant sensors — is reporting near-zero voltage no matter where the pedal is. Paired sibling of P2122 but on the redundant sensor circuit.
Read this codeThrottle/Pedal Position Sensor 'A'/'B' Voltage Correlation
The two throttle position sensors inside the throttle body don't agree with each other. On GM trucks and SUVs in particular this is THE 'Reduced Engine Power' code that strands owners on the shoulder — and the first thing to try is often a $10 can of throttle body cleaner.
Read this codeThrottle/Pedal Position Sensor 'D'/'E' Voltage Correlation
The two sensors inside the accelerator pedal don't agree with each other. Pedal-side mirror of P2135 — same correlation logic, but the failure is in the pedal under the dash, not in the throttle body. No cleaning will fix this one.
Read this codeNetwork & vehicle communication (U codes)
1 code published.
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About this code library
AutoLogicTools code pages provide general OBD-II trouble code information for planning conversations with a mechanic. A scan-tool reading is only the starting point. Verify diagnoses, parts, and labor with a qualified automotive professional before approving any repair.