OBD-II fault code lookup
Type any P, B, C or U code. Get a plain-English description, likely causes, severity and typical repair steps. Covers all standard SAE J2012 generic codes.
No trouble code
- •No fault currently detected
- ✓No action needed
A Camshaft Position Actuator Circuit (Bank 1)
- •VVT solenoid failure
- •Wiring damage
- •Low oil pressure
- ✓Replace VVT solenoid
- ✓Inspect oil level and pressure
- ✓Check wiring continuity
"A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1)
- •Faulty VVT solenoid
- •Dirty engine oil
- •Timing chain wear
- ✓Change engine oil and filter
- ✓Replace VVT solenoid
- ✓Inspect timing chain
Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor A)
- •Stretched timing chain
- •Faulty crank or cam sensor
- •VVT solenoid issue
- ✓Inspect timing chain stretch
- ✓Replace camshaft position sensor
- ✓Check VVT operation
HO2S Heater Control Circuit (Bank 1 Sensor 1)
- •Failed oxygen sensor heater
- •Blown fuse
- •Wiring issue
- ✓Replace O2 sensor
- ✓Check fuse and wiring
Mass or Volume Air Flow Circuit Malfunction
- •Dirty MAF sensor
- •Vacuum leak
- •Wiring damage
- ✓Clean MAF sensor
- ✓Inspect intake for leaks
- ✓Check MAF wiring
Mass or Volume Air Flow Circuit Range/Performance Problem
- •Dirty/contaminated MAF
- •Intake leak
- •Damaged intake tube
- ✓Clean MAF with MAF cleaner
- ✓Check intake tube integrity
- ✓Replace MAF if cleaning does not help
Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
- •Stuck-open thermostat
- •Faulty coolant temp sensor
- ✓Replace thermostat
- ✓Replace coolant temperature sensor
O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
- •Failed O2 sensor
- •Exhaust leak
- •Fuel system issue
- ✓Replace upstream O2 sensor
- ✓Check for exhaust leaks
- ✓Inspect fuel pressure
O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
- •Heater element in O2 sensor failed
- •Blown fuse
- •Wiring issue
- ✓Replace O2 sensor
- ✓Check heater circuit fuse and wiring
System Too Lean (Bank 1)
- •Vacuum leak
- •Weak fuel pump
- •Clogged fuel filter
- •Dirty MAF sensor
- ✓Smoke test for vacuum leaks
- ✓Check fuel pressure
- ✓Clean MAF sensor
- ✓Replace fuel filter
System Too Rich (Bank 1)
- •Leaking injector
- •Faulty MAF/MAP sensor
- •High fuel pressure
- •Restricted air filter
- ✓Replace air filter
- ✓Test injectors
- ✓Inspect MAF signal
- ✓Check fuel pressure regulator
System Too Lean (Bank 2)
- •Vacuum leak on Bank 2 side
- •Fuel delivery issue
- •Bad MAF
- ✓Inspect intake manifold gasket
- ✓Test fuel pressure
- ✓Clean MAF
System Too Rich (Bank 2)
- •Leaking injector on Bank 2
- •Bad MAF/MAP
- •High fuel pressure
- ✓Test Bank 2 injectors
- ✓Check fuel pressure regulator
- ✓Replace MAF if faulty
Random/Multiple Cylinder Misfire Detected
- •Worn spark plugs
- •Faulty ignition coils
- •Vacuum leak
- •Low fuel pressure
- •Timing chain issue
- ✓Replace spark plugs
- ✓Test ignition coils
- ✓Check compression
- ✓Inspect fuel system
Cylinder 1 Misfire Detected
- •Bad spark plug or coil on cyl 1
- •Clogged injector
- •Low compression in cyl 1
- ✓Swap coil/plug to check
- ✓Injector flow test
- ✓Compression test cyl 1
Cylinder 2 Misfire Detected
- •Bad spark plug or coil on cyl 2
- •Injector issue
- •Compression loss
- ✓Swap coil/plug to confirm
- ✓Test injector
- ✓Compression test
Cylinder 3 Misfire Detected
- •Spark plug/coil failure on cyl 3
- •Injector clogged
- •Valve issue
- ✓Replace spark plug and test coil
- ✓Clean/replace injector
- ✓Compression test
Cylinder 4 Misfire Detected
- •Coil or plug failure on cyl 4
- •Fuel or compression issue
- ✓Swap coil to isolate
- ✓Replace spark plug
- ✓Check compression
Cylinder 5 Misfire Detected
- •Ignition component on cyl 5
- •Injector or mechanical issue
- ✓Replace coil/plug on cyl 5
- ✓Test injector
- ✓Compression check
Cylinder 6 Misfire Detected
- •Cyl 6 spark or fuel issue
- •Timing / compression loss
- ✓Replace plug/coil
- ✓Injector test
- ✓Compression test
Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor)
- •Faulty knock sensor
- •Wiring corrosion
- •ECU issue
- ✓Replace knock sensor
- ✓Inspect sensor harness
- ✓Verify ECU response
Crankshaft Position Sensor A Circuit Malfunction
- •Faulty crank sensor
- •Damaged reluctor ring
- •Wiring fault
- ✓Replace crank sensor
- ✓Inspect reluctor wheel
- ✓Check wiring and connector
Camshaft Position Sensor A Circuit Malfunction
- •Bad cam sensor
- •Timing issue
- •Wiring damage
- ✓Replace camshaft sensor
- ✓Inspect timing
- ✓Check wiring harness
Exhaust Gas Recirculation Flow Insufficient Detected
- •Clogged EGR valve
- •Blocked EGR passages
- •Failed DPFE sensor
- ✓Clean or replace EGR valve
- ✓Clear EGR passages
- ✓Replace DPFE if faulty
Catalyst System Efficiency Below Threshold (Bank 1)
- •Failing catalytic converter
- •Bad downstream O2 sensor
- •Exhaust leak upstream
- ✓Replace catalytic converter if aged
- ✓Replace rear O2 sensor
- ✓Inspect exhaust for leaks
Catalyst System Efficiency Below Threshold (Bank 2)
- •Bank 2 cat failing
- •Rear O2 sensor fault
- •Exhaust leak
- ✓Replace cat
- ✓Replace downstream O2 sensor
- ✓Fix exhaust leaks
Evaporative Emission Control System Malfunction
- •Loose fuel cap
- •EVAP hose leak
- •Failed purge valve
- ✓Tighten or replace fuel cap
- ✓Smoke test EVAP system
- ✓Replace purge valve
Evaporative Emission Control System Leak Detected (small leak)
- •Loose gas cap
- •Small EVAP leak
- •Hose crack
- ✓Check fuel cap seal
- ✓EVAP smoke test
- ✓Replace cracked hose
Evaporative Emission Control System Leak Detected (gross leak)
- •Fuel cap off or broken
- •Large EVAP hose leak
- •Charcoal canister cracked
- ✓Replace fuel cap
- ✓Locate and fix large leak
- ✓Replace canister
Vehicle Speed Sensor Malfunction
- •Failed VSS
- •ABS sensor issue
- •Wiring damage
- ✓Replace speed sensor
- ✓Inspect ABS system
- ✓Check wiring
Idle Control System RPM Lower Than Expected
- •Dirty throttle body
- •Vacuum leak
- •IAC valve fault
- ✓Clean throttle body
- ✓Smoke test for leaks
- ✓Replace IAC valve
Idle Control System RPM Higher Than Expected
- •Vacuum leak
- •Sticking throttle
- •Faulty IAC valve
- ✓Inspect intake for leaks
- ✓Clean throttle plate
- ✓Replace IAC
System Voltage Low
- •Failing alternator
- •Weak battery
- •Corroded cables
- ✓Test alternator output
- ✓Load-test battery
- ✓Clean battery terminals
Transmission Control System Malfunction
- •Internal transmission fault
- •TCM issue
- •Low/burnt fluid
- ✓Pull transmission sub-codes
- ✓Inspect fluid
- ✓Visit transmission specialist
Output Speed Sensor Circuit Malfunction
- •Failed output speed sensor
- •Wiring issue
- •Valve body problem
- ✓Replace output speed sensor
- ✓Inspect harness
- ✓Check valve body
Incorrect Gear Ratio
- •Slipping clutch/band
- •Solenoid fault
- •Low fluid
- ✓Check fluid level and condition
- ✓Test shift solenoids
- ✓Transmission rebuild if severe
Torque Converter Clutch Circuit Malfunction
- •Bad TCC solenoid
- •Low fluid
- •Failed torque converter
- ✓Replace TCC solenoid
- ✓Check fluid
- ✓Inspect torque converter
Shift Solenoid A Malfunction
- •Failed shift solenoid
- •Valve body issue
- •Wiring fault
- ✓Replace solenoid A
- ✓Inspect valve body
- ✓Check harness
Driver Frontal Stage 1 Deployment Control
- •SRS airbag circuit fault
- •Clock spring failure
- •Damaged wiring
- ✓SRS scan tool diagnosis
- ✓Replace clock spring
- ✓Specialist airbag service
Battery Voltage Low
- •Weak battery
- •Parasitic draw
- •Alternator issue
- ✓Load-test and replace battery if needed
- ✓Find parasitic draw
- ✓Check alternator
Left Front Wheel Speed Sensor Circuit
- •Failed wheel speed sensor
- •Damaged tone ring
- •Wiring fault
- ✓Replace LF wheel speed sensor
- ✓Inspect tone ring
- ✓Check connector and harness
Right Front Wheel Speed Sensor Circuit
- •RF wheel speed sensor fault
- •Connector corrosion
- •Reluctor issue
- ✓Replace RF sensor
- ✓Clean/replace connector
- ✓Check reluctor ring
EBCM Relay Circuit Malfunction
- •EBCM internal fault
- •Relay failure
- •Wiring issue
- ✓Run EBCM self-test
- ✓Replace relay
- ✓Inspect harness
Lost Communication With ECM/PCM A
- •Dead ECM/PCM
- •CAN bus failure
- •Bad ground
- ✓Check battery and grounds
- ✓CAN bus integrity test
- ✓ECM reprogramming / replacement
Lost Communication with TCM
- •TCM power/ground issue
- •CAN wiring fault
- •Failed TCM
- ✓Verify TCM power
- ✓CAN bus test
- ✓Replace TCM if confirmed
Lost Communication With ABS Control Module
- •ABS module failure
- •CAN bus short
- •Blown fuse
- ✓Check ABS fuse
- ✓Run CAN bus diagnostic
- ✓Replace ABS module if dead
Lost Communication With Instrument Panel Cluster
- •Cluster power fault
- •CAN issue
- •Cluster internal failure
- ✓Check cluster fuses
- ✓CAN continuity test
- ✓Replace cluster
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