Common Check Engine Light Codes

Actron 9580 Scan Tool

We list common check engine light codes for you on this page at the bottom. This isn’t a complete or exhaustive list of every code that could set in your computer’s memory.

Instead, I went through the entire OBD II code list and picked out codes I’ve seen set in the real auto repair world. I also included a short description of what the check engine light means so you don’t have to hunt a definition down elsewhere.

In fact many of the check engine light codes I deal with on a daily basis are in the P0300-P0400 range. if you’re wondering what P0171 in the picture on the right stands for, it’s Fuel system lean Bank 1. The PO300 series of codes relate to engine misfires. A 300 is for a random misfire as a 301 represents a misfire detected on cylinder number one.

Common Diagnostic Trouble codes

The P0300-P0310 range can often cause the check engine light to flash. The light flashes to grab the drivers attention. These codes are serious and could allow raw fuel to pool up in the catalytic converter. A flashing check engine light means pull over and tow the vehicle to prevent damage. auto repair manualsThe P0400 codes relate to the emissions system and fuel vapor leaks (Gas Cap Codes). These in my opinion remain common and can experience intermittent failures. We provide diagnostic examples in the auto repair video below.

Often it depends on the make and model automobile. Repair trends for diagnostic trouble codes become a moving target as new issues develop regularly. I have an in depth page that supplies problem solving diagnostic tips. If you’re looking for pages covering specific issues I have many.

The individual articles focus on repair and diagnosis of common check engine light problems. Note that these articles started out by highlighting things I run into as a fleet technician. We might not cover your exact problem yet. However, this site adds new information on a regular basis, so check back at the auto repair blog.

General Check Engine Light Diagnosis

Dodge Caravan 1995-2001 Belt Diagram
Dodge Caravan 1995-2001 Belt Diagram

If we haven’t covered your specific car problems in any of these articles, then follow a factory issued diagnostic chart for the particular service engine soon light failure.

I diagnose OBD II check engine light codes all the time. I still find it necessary to refer to a professional auto repair diagram to efficiently solve the problem.

Below the car code list find the link to an online factory car repair manual. I use them for complex diagnosis. I find it a highly effective tool in the fight against the engine lamp.

Professional mechanics believe the quickest way to diagnose check engine light codes is with a vehicle specific diagram. Learn more about the online car repair manuals available on this website. A few bucks can put you on a successful path by following the factory diagnostic chart in minutes.

OBD II Check Engine Light Code Definitions

  • P0016 Crankshaft or Camshaft Timing Misalignment Reported
  • P0037 Heated O2S (Bank 1 Sensor 2) Heater Relay Circuit Low
  • P0038 Heated O2S (Bank 1 Sensor 2) Heater Relay Circuit High
  • P0051 Heated O2S (Bank 2 Sensor 1) Heater Relay Circuit Low
  • P0052 Heated O2S (Bank 2 Sensor 1) Heater Relay Circuit High
  • P0056 HO2S (Bank 2 Sensor 1) Heater Relay Circuit Malfunction
  • P0057 HO2S (Bank 2 Sensor 1) Heater Relay Circuit Low Input
  • P0058 HO2S (Bank 2 Sensor 1) Heater Relay Circuit High Input
  • P0070 Battery Temperature Sensor Circuit Stuck
  • P0072 Battery Temperature Sensor Circuit Low Input
  • P0073 Battery Temperature Sensor Circuit High Input
  • P0107 Manifold Absolute Pressure Sensor Low Input
  • P0108 M.A.P. Sensor High Input
  • P0111 Intake Air Temperature Sensor Range/Performance
  • P0112 Intake Air Temperature Circuit Low Input
  • P0113 Intake Air Temperature Sensor Circuit High Input
  • P0117 Engine Coolant Temperature Sensor Circuit Low Input
  • P0118 Engine Coolant Temperature Sensor Circuit High Input
  • P0121 Throttle Position Sensor Does Not Agree With MAP
  • P0122 T.P.S. Circuit Low Input
  • P0123 T.P.S. Circuit High Input
  • P0125 Closed Loop Operation Temperature Not Reached
  • P0129 Barometric Pressure Sensor Out-Of-Range Low
  • P0131 HO2S (Bank 1 Sensor 1) Signal Low Input
  • P0132 HO2S (Bank 1 Sensor 1) Signal Shorted to Voltage
  • P0133 HO2S (Bank 1 Sensor 1) Slow Response
  • P0135 HO2S (Bank 1 Sensor 1) Heater Circuit Malfunction
  • P0136 HO2S (Bank 1 Sensor 2) Heater Relay Circuit Low Input
  • P0137 HO2S (Bank 1 Sensor 2) Signal Low Input
  • P0138 HO2S (Bank 1 Sensor 2) Signal Shorted to Voltage
  • P0141 HO2S (Bank 1 Sensor 2) Heater Circuit Malfunction
  • P0165 Starter Relay Circuit Malfunction
  • P0171 Fuel System Lean (Bank 1)
  • P0172 Fuel System Rich (Bank 1)
  • P0174 Fuel System Lean (Bank 2)
  • P0175 Fuel System Rich (Bank 2)
  • P0201 Fuel Injector 1 Control Circuit Malfunction
  • P0202 Fuel Injector 2 Control Circuit Malfunction
  • P0203 Fuel Injector 3 Control Circuit Malfunction
  • P0204 Fuel Injector 4 Control Circuit Malfunction
  • P0205 Fuel Injector 5 Control Circuit Malfunction
  • P0206 Fuel Injector 6 Control Circuit Malfunction
  • P0207 Fuel Injector 7 Control Circuit Malfunction
  • P0208 Fuel Injector 8 Control Circuit Malfunction
  • P0300 Multiple Cylinder Misfire Detected
  • P0301 Cylinder 1 Misfire Detected
  • P0302 Cylinder 2 Misfire Detected
  • P0303 Cylinder 3 Misfire Detected
  • P0304 Cylinder 4 Misfire Detected
  • P0305 Cylinder 5 Misfire Detected
  • P0306 Cylinder 6 Misfire Detected
  • P0307 Cylinder 7 Misfire Detected
  • P0308 Cylinder 8 Misfire Detected
  • P0315 Crankshaft Position Sensor Not Learned
  • P0320 No Crank Reference Signal to PCM
  • P0339 Crankshaft Position Sensor Circuit Malfunction
  • P0340 No Camshaft Signals At PCM
  • P0344 Camshaft Position Sensor Circuit Intermittent
  • P0351 Ignition Coil 1 Primary Circuit Malfunction
  • P0420 Catalyst Efficiency Below Normal (Bank 1)
  • P0432 Catalyst Efficiency Below Normal (Bank 2)
  • P0440 Evaporative Emission Control System Leak Detected
  • P0441 EVAP Purge Flow Monitor Fault
  • P0442 EVAP System Small Leak Detected
  • P0443 EVAP Purge Solenoid Circuit Malfunction
  • P0455 EVAP System Large Leak Detected
  • P0456 EVAP Leak Monitor Leak Medium Detected
  • P0460 Fuel Level Sensor Unit No Change Over Miles
  • P0461 Fuel Level Sensing Unit No Change Over Miles
  • P0462 Fuel Level Sensor Unit Volts Too Low
  • P0463 Fuel Level Sensor Unit Volts Too High
  • P0500 Vehicle Speed Sensor Signal Circuit Malfunction
  • P0505 Idle Air Control Motor Circuit Malfunction
  • P0522 Engine Oil Pressure Sensor Circuit Low Input
  • P0523 Engine Oil Pressure Sensor Circuit High Input
  • P0600 PCM Internal Failure or No SPI Communications
  • P0601 PCM Random Access Memory Failure or Self-Test Failed
  • P0700 Automatic Transmission System Malfunction Detected
  • P0705 A/T Check Shifter Signal Circuit Malfunction
  • P0711 A/T Trans Fluid Temperature Sensor Signal-No increase
  • P0712 A/T Transmission Fluid Temperature Sensor Low Input
  • P0713 A/T Transmission Fluid Temperature Sensor High Input
  • P0720 Output Speed Sensor – Low Output Above 15 MPH
  • P0740 A/T Torque Converter Clutch – No RPM Drop at Lockup
  • P0743 A/T Transmission Relay Circuit Malfunction
  • P0748 A/T Governor Pressure Solenoid/Transmission Relay Fault
  • P0751 A/T Overdrive Switch Pressed Low For Over 5 Minutes
  • P0753 A/T 3-4 Solenoid/Transmission Relay Circuit Malfunction
  • P1195 HO2S-11 (Bank 1 Sensor 1) Signal Insufficient Activity
  • P1196 HO2S-21 (Bank 2 Sensor 1) Signal Insufficient Activity
  • P1281 Engine Is Cold Too Long
  • P1282 Fuel Pump Relay Control Circuit Malfunction
  • P1294 Target Idle Speed Not Reached
  • P1296 5-Volt Voltage Reference Signal Supply Not Present
  • P1297 No MAP Signal From Start To Running Transition
  • P1299 Vacuum Leak Present With IAC Valve Fully Seated
  • P1388 ASD Relay Control Circuit Malfunction
  • P1389 No ASD Relay Voltage At PCM
  • P1391 Crank or Cam Sensor Signal Malfunction (Intermittent)
  • P1398 Misfire Adaptive Numerator At Limit
  • P1486 EVAP Leak Detection Monitor Pinched Hose Detected
  • P1491 Radiator Fan Control Relay Circuit Malfunction
  • P1494 EVAP System Detection Pump Switch Or Mechanical Fault
  • P1495 No CCD Messages Received From The BCM
  • P1740 Trans TCC or Overdrive Solenoid PSI In Gear At 0 MPH
  • P1756 A/T Governor Pressure Not Equal To Target At 15-20 PSI
  • P1757 A/T Governor Pressure Above 3 PSI In Gear At 0 MPH
  • P1762 A/T Governor Pressure Sensor Offset Volts Too High/Low
  • P1763 A/T Governor Pressure Sensor Signal Too High
  • P1764 A/T Governor Pressure Sensor Signal Too Low
  • P1765 A/T Switched Battery Malfunction
  • P1899 Auto Trans Park Neutral Switch Stuck in Park Position.

Learn More about Diagnostic Trouble codes

Find out more about how these malfunctions actually help you fix cars and why they set in the computers memory. Also specific articles for repairing the most common car problems. This next link takes you to a page about what the code digits stand for.

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