Block of codes
P06xx codes: computer and output circuits
This block brings together the codes from P0600 to P06D1 in the glossary. Open yours to see what it means, its causes and whether you can keep driving.
Reviewed by Daniel Morales, founder of Reprorace SL, on
What this block covers
Control modules and outputs
The car's control units and the reference voltages they feed their sensors with. Sometimes the fault is in the control unit; often it is in its power supply or wiring.
Engine (mechanical, cooling and lubrication)
The engine's mechanics, timing (camshaft and crankshaft), cooling and lubrication. Many of these codes check that the engine is in time and at the right temperature.
Fuel and air metering
The engine measures the incoming air and meters the fuel so the mixture is right; the throttle, the accelerator pedal and the turbo are here too. A fault usually shows as higher fuel use, jerking, lack of power or hard starting.
Electrical system (12 V, starting and charging)
The battery, charging and the 12 V system and, on diesels, the glow plugs that help the engine start from cold.
Speed, idle and auxiliary inputs
The vehicle speed sensors and idle control, the speed the engine turns at when you are not accelerating.
Emission control
The catalytic converter, oxygen sensors, EGR, fuel vapor system (EVAP), particulate filter and NOx reduction clean the exhaust. A fault here raises pollution and may make the car fail its inspection; left alone, some end in a bigger fault or in limp-home mode.
Ignition and misfire
Spark plugs and coils make the spark that burns the mixture in each cylinder. If a cylinder does not fire properly, the engine shakes and loses power, and unburnt fuel can damage the catalytic converter.
Transmission
The gearbox, especially automatic ones: its sensors, solenoids and torque converter. A fault may lock it in one gear (limp-home mode) or cause harsh shifts.
The 168 codes of the block
- P0600Serial communication link: malfunction
- P0601Internal control module memory checksum: error
- P0602Control module programming: error
- P0603Internal control module keep alive memory (KAM): error
- P0604Internal control module random access memory (RAM): error
- P0605Internal control module read only memory (ROM): error
- P0606Control module: processor fault
- P0607Control module: performance
- P0608Control module VSS output A: malfunction
- P0609Control module VSS output B: malfunction
- P060AInternal control module monitoring: processor fault
- P060BInternal control module A/D processing: performance
- P060CInternal control module main: processor fault
- P060DInternal control module accelerator pedal position: performance
- P060EInternal control module throttle position: performance
- P060FInternal control module coolant temperature: performance
- P0610Control module vehicle options: error
- P0611Fuel injector control module: performance
- P0612Fuel injector control module relay control: malfunction
- P0613TCM: processor fault
- P0614ECM/TCM incompatible
- P0615Starter relay A, circuit: malfunction
- P0616Starter relay A, circuit: signal low
- P0617Starter relay A, circuit: signal high
- P0618Alternative fuel control module KAM: error
- P0619Alternative fuel control module RAM/ROM: error
- P061AInternal control module torque: performance
- P061BInternal control module torque calculation: performance
- P061CInternal control module engine RPM: performance
- P061DInternal control module engine air mass: performance
- P061EInternal control module brake signal: performance
- P061FInternal control module throttle actuator controller: performance
- P0620Generator, control circuit: malfunction
- P0621Generator lamp/L terminal, circuit: malfunction
- P0622Generator field/F terminal, circuit: malfunction
- P0623Generator lamp, control circuit: malfunction
- P0624Fuel cap lamp, control circuit: malfunction
- P0625Generator field/F terminal, circuit: signal low
- P0626Generator field/F terminal, circuit: signal high
- P0627Fuel pump A, control circuit open
- P0628Fuel pump A, control circuit: signal low
- P0629Fuel pump A, control circuit: signal high
- P062AFuel pump A, control circuit: range/performance
- P062BInternal control module fuel injector control: performance
- P062CInternal control module vehicle speed: performance
- P062DFuel injector (bank 1), driver circuit: performance
- P062EFuel injector (bank 2), driver circuit: performance
- P0630VIN: not programmed or incompatible - ECM/PCM
- P0631VIN: not programmed or incompatible - TCM
- P0632Odometer: not programmed - ECM/PCM
- P0633Immobilizer key: not programmed - ECM/PCM
- P0634Control module internal temperature A: too high
- P0635Power steering, control circuit: malfunction
- P0636Power steering, control circuit: signal low
- P0637Power steering, control circuit: signal high
- P0638Throttle actuator control (bank 1): range/performance
- P0639Throttle actuator control (bank 2): range/performance
- P063EAuto configuration throttle input (bank 1): not present
- P063FAuto configuration engine coolant temperature input: not present
- P0640Intake air heater, control circuit: malfunction
- P0641Sensor reference voltage A, circuit open
- P0642Sensor reference voltage A, circuit: signal low
- P0643Sensor reference voltage A, circuit: signal high
- P0644Driver display, serial communication circuit: malfunction
- P0645A/C clutch relay, control circuit: malfunction
- P0646A/C clutch relay, control circuit: signal low
- P0647A/C clutch relay, control circuit: signal high
- P0648Immobilizer lamp, control circuit: malfunction
- P0649Speed control lamp, control circuit: malfunction
- P064AFuel pump control module A: malfunction
- P064BPTO control module: malfunction
- P064CGlow plug control module 1: malfunction
- P064DInternal control module O2 sensor (bank 1): processor fault
- P064EInternal control module O2 sensor (bank 2): processor fault
- P064FUnauthorized software/calibration: detected
- P0651Sensor reference voltage B, circuit open
- P0652Sensor reference voltage B, circuit: signal low
- P0653Sensor reference voltage B, circuit: signal high
- P0654Engine RPM, output circuit open
- P0655Engine hot lamp output, control circuit: malfunction
- P0656Fuel level, output circuit: malfunction
- P0657Actuator supply voltage A, circuit open
- P0658Actuator supply voltage A, circuit: signal low
- P0659Actuator supply voltage A, circuit: signal high
- P065AGenerator system: performance
- P065DReductant system malfunction lamp, control circuit: malfunction
- P065EIntake manifold tuning valve (bank 1): performance
- P065FIntake manifold tuning valve (bank 2): performance
- P0660Intake manifold tuning valve (bank 1), control circuit open
- P0661Intake manifold tuning valve (bank 1), control circuit: signal low
- P0662Intake manifold tuning valve (bank 1), control circuit: signal high
- P0663Intake manifold tuning valve (bank 2), control circuit open
- P0664Intake manifold tuning valve (bank 2), control circuit: signal low
- P0665Intake manifold tuning valve (bank 2), control circuit: signal high
- P0666Control module internal temperature sensor A, circuit: malfunction
- P0667Control module internal temperature sensor A: range/performance
- P0668Control module internal temperature sensor A, circuit: signal low
- P0669Control module internal temperature sensor A, circuit: signal high
- P066ACylinder 1 glow plug, control circuit: signal low
- P066BCylinder 1 glow plug, control circuit: signal high
- P066CCylinder 2 glow plug, control circuit: signal low
- P066DCylinder 2 glow plug, control circuit: signal high
- P066ECylinder 3 glow plug, control circuit: signal low
- P066FCylinder 3 glow plug, control circuit: signal high
- P0670Glow plug control module 1, control circuit open
- P0671Cylinder 1 glow plug, circuit open
- P0672Cylinder 2 glow plug, circuit open
- P0673Cylinder 3 glow plug, circuit open
- P0674Cylinder 4 glow plug, circuit open
- P0675Cylinder 5 glow plug, circuit open
- P0676Cylinder 6 glow plug, circuit open
- P0677Cylinder 7 glow plug, circuit open
- P0678Cylinder 8 glow plug, circuit open
- P0679Cylinder 9 glow plug, circuit open
- P067ACylinder 4 glow plug, control circuit: signal low
- P067BCylinder 4 glow plug, control circuit: signal high
- P0680Cylinder 10 glow plug, circuit open
- P0681Cylinder 11 glow plug, circuit open
- P0682Cylinder 12 glow plug, circuit open
- P0683Communication circuit between glow plug control module 1 and PCM: malfunction
- P0684Communication circuit between glow plug control module 1 and PCM: range/performance
- P0685ECM/PCM power relay, control circuit open
- P0686ECM/PCM power relay, control circuit: signal low
- P0687ECM/PCM power relay, control circuit: signal high
- P0688ECM/PCM power relay, sense circuit open
- P0689ECM/PCM power relay, sense circuit: signal low
- P068AECM/PCM power relay: de-energizing behavior incorrect - too early
- P068BECM/PCM power relay: de-energizing behavior incorrect - too late
- P0690ECM/PCM power relay, sense circuit: signal high
- P0691Fan 1, control circuit: signal low
- P0692Fan 1, control circuit: signal high
- P0693Fan 2, control circuit: signal low
- P0694Fan 2, control circuit: signal high
- P0695Fan 3, control circuit: signal low
- P0696Fan 3, control circuit: signal high
- P0697Sensor reference voltage C, circuit open
- P0698Sensor reference voltage C, circuit: signal low
- P0699Sensor reference voltage C, circuit: signal high
- P069EFuel pump control module requested MIL illumination: malfunction
- P069FThrottle actuator control lamp, control circuit: malfunction
- P06A0Variable A/C compressor, control circuit: malfunction
- P06A1Variable A/C compressor, control circuit: signal low
- P06A2Variable A/C compressor, control circuit: signal high
- P06A3Sensor reference voltage D, circuit open
- P06A4Sensor reference voltage D, circuit: signal low
- P06A5Sensor reference voltage D, circuit: signal high
- P06A6Sensor reference voltage A, circuit: range/performance
- P06A7Sensor reference voltage B, circuit: range/performance
- P06A8Sensor reference voltage C, circuit: range/performance
- P06A9Sensor reference voltage D, circuit: range/performance
- P06AAControl module internal temperature B: too high
- P06ABControl module internal temperature sensor B, circuit: malfunction
- P06ACControl module internal temperature sensor B: range/performance
- P06ADControl module internal temperature sensor B, circuit: signal low
- P06AEControl module internal temperature sensor B, circuit: signal high
- P06B0Sensor power supply A, circuit open
- P06B1Sensor power supply A, circuit: signal low
- P06B2Sensor power supply A, circuit: signal high
- P06B3Sensor power supply B, circuit open
- P06B4Sensor power supply B, circuit: signal low
- P06B5Sensor power supply B, circuit: signal high
- P06B6Internal control module knock/combustion vibration sensor processor 1: performance
- P06B7Internal control module knock/combustion vibration sensor processor 2: performance
- P06B9Cylinder 1 glow plug, circuit: range/performance
- P06BACylinder 2 glow plug, circuit: range/performance
- P06BBCylinder 3 glow plug, circuit: range/performance
- P06BCCylinder 4 glow plug, circuit: range/performance
- P06D1Internal control module ignition coil control: performance
Other blocks
Read your car's fault codes on your phone
With an ECO-LITE in the OBD socket you see the codes in your account, with the data captured when the fault happened, and your workshop can check them remotely, always with your permission.
Keep reading
- OBD fault codes: what each one means
- Check engine light on: what to do
- How to read and clear your car's fault codes
- Will your car pass its MOT or inspection with the engine light on?
- Wi-Fi OBD2 reader: which one to choose
- Reading fault codes by car make
- Remote OBD diagnostics: what it is, how it works and what it can't do
- Vehicle diagnostics glossary