Powertrain, generic · Computer and auxiliary outputs

P0650 MIL Control Circuit/Open

Check engine lightUsually off
EmissionsRelevant
Drive cycleRequired
Limp modeNo

The engine module switches the check engine light (MIL) through a low-side driver – or sends the command over CAN – and monitors the circuit: with the lamp off the line must carry supply voltage, with it on nearly 0 V. CARB requires the MIL to light for a bulb check at ignition on with the engine off (at least 15 s since model year 2005). GM's 2018–2025 modules use P0650 only for an open circuit (200 kΩ or more, above 11 V, 50 ms) and P263A/P263B for shorts to ground and voltage – stored without lighting the MIL, since a broken MIL cannot report itself; older GM diesels combine all faults in P0650. GM Europe's Saab 9-5 V6 checks only once the MIL has been commanded on and off. The engine runs normally, but emission faults go unseen and inspections fail if the lamp does not light at the bulb check.

Likely causes

Wire or connector between engine module and instrument cluster open or corroded
MIL bulb burnt out or LED/instrument cluster faulty
MIL supply in the cluster missing (fuse, ignition feed)
Short in the circuit (at GM reported as P263A/P263B)
Output driver in the module faulty

Symptoms

  • MIL does not light at the bulb check
  • MIL stays on (with a short or combined code)
  • Code only visible with a scan tool, engine runs normally
  • Failed emissions inspection

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–500
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

malfunction indicator lampinstrument clusterlamp control circuit

Related codes

P263AP263BP0802U0155P0606

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.