OBD-II code · Powertrain (generic)
P0605 Internal Control Module Read Only Memory (ROM) Error
ECU self-test detected a ROM/checksum failure on the program memory. The control software cannot be trusted; vehicle typically defaults to limp-home with reduced function.
Is it safe to drive with P0605?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyECU internal ROM fault
- Less likelyModule software outdated, reflash may resolve
- Less likelySupply voltage outside specification
Symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–4 h
- Emissions test
- Usually unaffected
- Parts involved
- Ecm
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.