P262B code meaning
Control Module Power Off Timer Performance
Powertrain system Generic code P26xx codes Check engine light
What P262B means
P262B concerns the timer that keeps counting inside a control module while the vehicle is shut down, used to measure how long it has been off. GM runs two checks on it: a count-up test while run/crank is inactive, failing when two consecutive readings differ by over 1.5 s in 4 of 20 one-second samples, and a range test comparing the hardware timer with a mirror timer at shutdown or restart (deviation above 25 % in the 2014 tables). It is Type B, so the MIL follows on the second trip. GM saw false sets on 2019–2020 CT6 4.2 L engines when the engine cooled faster than expected, for example in wind or an air-conditioned garage (PIP5754: clear the code and keep the ECM), and links P262B to ECM supply or ground faults (PIP5609) and to a lost ignition relay feed (PIT5391).
P262B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor0.3 to 2.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P262B
- MIL on after two drive cycles
- Possibly other control module codes stored at the same time
Common causes of P262B
- Most likelyPoor ECM power or ground connection, momentary supply loss
- PossibleIgnition relay or its control circuit not supplying the module
- PossibleDiagnostic calibration too sensitive to fast engine cool-down
- Less likelyInternal timer hardware fault in the control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Control moduleMain relay
What each part of P262B means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 6 | Area: computer (engine control module) and output circuits. |
| 2B | The exact fault in that area. |
What to do next
- Note P262B and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P262B
What does P262B mean?
P262B means "Control Module Power Off Timer Performance". P262B concerns the timer that keeps counting inside a control module while the vehicle is shut down, used to measure how long it has been off. It is a generic code, so it means the same on every make.
Is it safe to drive with P262B?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P262B fail an emissions test?
Yes, it can. P262B is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P262B to fix?
Difficulty: workshop only. A typical repair takes 0.3 to 2.5 hours of work. This is a job for a workshop.
Will P262B clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.