Electrical and sensors

P0650 — Malfunction Indicator Lamp (MIL) Control Circuit Fault

Severity: low Safe to drive

What P0650 means

The engine control module (ECM) turns the check engine light on and off by switching the ground on the lamp circuit. P0650 sets when the voltage in that circuit does not match what the ECM commanded, for example due to an open, a short or a failed driver inside the ECM. The light may then stay off at key-on or stay on all the time.

Symptoms

  • Check engine light does not come on at key-on
  • Light stays on or flickers for no clear reason
  • P0650 stored in the ECM
  • Other faults go unnoticed because the lamp does not work
  • Failed emissions inspection or readiness check

Possible causes

  1. Burned out bulb or LED in the instrument cluster
  2. Faulty instrument cluster
  3. Open or shorted wire between the ECM and the cluster
  4. Corroded or damaged connector pins
  5. Failed MIL driver inside the ECM
  6. Missing power or ground at the cluster (blown fuse, bad ground)

How to diagnose

  1. Scan all codes, save freeze frame data, clear P0650 and see if it returns
  2. Turn the key on and watch whether the cluster bulb check runs
  3. Check the fuses and the power and ground feeds to the instrument cluster
  4. Inspect the ECM and cluster connectors for corrosion, moisture and loose pins
  5. Test the MIL control wire for opens, shorts to ground and shorts to voltage
  6. Check the bulb or LED and the cluster itself
  7. Command the lamp on with a scan tool if supported and measure the ECM output signal
  8. If wiring and cluster are good, test or replace the ECM

Common fixes

  • Replace the bulb or LED in the cluster
  • Repair or replace the damaged wire or connector
  • Restore cluster power and ground, replace a blown fuse
  • Repair or replace the instrument cluster
  • Repair, reflash or replace the ECM

Questions and answers

What does P0650 mean?

The ECM detected a problem in the check engine light control circuit. The bulb, cluster or wiring is the usual culprit, and the ECM itself is less common.

Can I drive with code P0650?

Usually yes, since the engine is not affected. But a lamp that does not work will not warn you about other problems, so do not put the repair off for long.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.