P0650
Malfunction Indicator Lamp (MIL) Control Circuit
- Severity
- Medium
- Driving
- Drivable — book it in
A fault in the check engine lamp control circuit. The module cannot control the warning lamp reliably, so it may stay on, stay off, or behave inconsistently. The important case is the lamp that cannot light: the vehicle could store a serious fault and never tell you.
Possible causes
- CommonBlown indicator bulb
- CommonWiring or connector fault between the module and the cluster
- PossibleFailed instrument cluster lamp driver
- PossibleCorroded connector behind the cluster
- RareFailed control module output driver
What you might notice
- Check engine light permanently on with no other codes
- Check engine light never lighting, including at ignition-on
- Lamp flickering
- Emissions test refused
What to check, in order
- Watch the lamp at ignition-on. It should light and then go out once the engine starts - that self-test is exactly what an inspection checks for.
- A lamp that does not light at all is an inspection failure in most jurisdictions, because the tester cannot confirm the warning system works.
- Check the bulb or the cluster segment.
- Check the wiring between the module and the cluster.
- Treat a permanently lit lamp with no other codes as suspicious - read the codes properly rather than assuming the lamp is at fault.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Computer output circuits and control module
P0600P0601P0602P0603P0604P0605P0606P0607P0608P0609P0610P0611P0612P0613P0614P0615P0616P0617P0618P0619P0620P0621P0622P0623P0624P0625P0626P0627P0628P0629P0630P0631P0632P0633P0634P0635P0636P0637P0638P0639P0640P0641P0642P0643P0644P0645P0646P0647P0648P0649P0650P0651P0652P0653P0654P0655P0656P0657P0658P0659P0660P0661P0662P0663P0664P0665P0666P0667P0668P0669P0670P0671P0672P0673P0674P0675P0676P0677P0678P0679P0680P0681P0682P0683P0684P0685P0686P0687P0688P0689P0690P0691P0692P0693P0694P0695P0696P0697P0698P0699