OBD-II · Engine and powertrain (P)
P0602
Control module programming error
What it means
The ECU is not programmed or its programming is incomplete, often after an interrupted software update.
Symptoms
- engine warning light
- possible limp mode, stalling or no start
- sometimes no noticeable change
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | interrupted or failed software update or remap |
| 02 | wrong software loaded |
| 03 | replacement ECU not programmed |
| 04 | low voltage during programming |
What to check, step by step
- 01Check the battery, charging voltage and the ECU power supplies and earths
- 02Clear the code and see whether it returns
- 03Inspect the ECU and its connectors for water ingress or corrosion
- 04Check for a software update from the maker, or whether the ECU has been remapped
- 05Reprogram the ECU with a stable power supply connected, or repair/replace it (a replacement usually needs coding and immobiliser matching)