DTC codes
Look up an OBD-II fault code: what it means on every car or on your make, and how to track it down.
How to read a code
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 4
- AreaAuxiliary emission controls
- 20
- FaultThe specific fault in that area
Read the code
Note every stored and pending code your scanner shows, such as P0420.
Find it
Search by code or by words. For a manufacturer code (P1, B1, C1, U1) pick your make: its meaning differs by make.
Open the code
Its page explains the symptoms, likely causes, the checks to run and the fixes.
- U0661Generic · NetworkLost Communication With Right Rear Temperature Actuator A
- U0662Generic · NetworkLost Communication With Right Rear Temperature Actuator B
- U0663Generic · NetworkLost Communication With Rear Mode Actuator
- U0664Generic · NetworkLost Communication With Rear HVAC Air Cutoff Actuator
- U0665Generic · NetworkLost Communication With Fuel Rail Pressure Sensor Bank 2
- U0666Generic · NetworkLost Communication With Reductant Pressure Sensor
- U0667Generic · NetworkLost Communication With Engine Oil Temperature Sensor A
- U0668Generic · NetworkLost Communication With Engine Oil Level Sensor Circuit
- U0669Generic · NetworkLost Communication With EGR Sensor D
- U066AGeneric · NetworkLost Communication With EGR Sensor E
- U066BGeneric · NetworkLost Communication With Turbocharger/Supercharger Bypass Valve B Position Sensor
- U066CGeneric · NetworkLost Communication With Exhaust Heat Exchanger Bypass Valve Actuator B
- U066DGeneric · NetworkLost Communication With Charge Air Cooler Temperature Sensor Bank 1
- U066EGeneric · NetworkLost Communication With Charge Air Cooler Temperature Sensor Bank 2
- U066FGeneric · NetworkLost Communication With Low Pressure Fuel System Sensor
- U0670Generic · NetworkLost Communication With Fuel Temperature Sensor A
- U0671Generic · NetworkLost Communication With Fuel Temperature Sensor B
- U0672Generic · NetworkLost Communication With Engine Coolant Pump
- U0673Generic · NetworkLost Communication With Ion Sense Module
- U0674Generic · NetworkLost Communication With Wastegate Position Sensor B
- U0675Generic · NetworkLost Communication With Turbocharger/Supercharger Speed Sensor A
- U0676Generic · NetworkLost Communication With Fuel Level Sensor A
- U0677Generic · NetworkLost Communication With Fuel Level Sensor B
- U0678Generic · NetworkLost Communication With Fuel Level Sensor C
- U0679Generic · NetworkLost Communication With Transmission Fluid Pressure Sensor/Switch A
- U067AGeneric · NetworkLost Communication With Transmission Fluid Pressure Sensor/Switch B
- U067BGeneric · NetworkLost Communication With Engine Disconnect Clutch Pressure Sensor
- U067CGeneric · NetworkLost Communication With Fan 3
- U067DGeneric · NetworkLost Communication With Fan 4
- U067EGeneric · NetworkLost Communication With Exhaust Pressure Control Valve B Sensor/Switch