The engine ECU has failed its own internal memory check. Genuine ECU failure is rarer than people think — check power and earths first.
P0605 — also written PO6O5, P 0605, 0605 — is the OBD-II code for internal control module rom error. Same code, same fix: this page covers every spelling of it.
P0605 is a electrical fault code, typically costing £150–£1600 to put right in a UK garage.
What causes P0605?
- Corrupted ECU software after a flat battery or bad jump start
- Water ingress into the ECU housing
- Poor earth causing voltage spikes
- Genuine internal ECU failure
How P0605 is fixed
- Check ECU supply and earth integrity
- Try a software re-flash with the latest calibration
- Use a specialist ECU repair service before buying new — usually far cheaper
- Replace and code the ECU as a last resort
P0605 repair cost in the UK
Most P0605 repairs land between £150–£1600 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Can you drive with P0605?
May not start or may cut out. Recover rather than risk it.
Urgency: high.