P0605 Code: Internal Control Module Read Only Memory (ROM) Error
🟠 Moderate severity · drivable
Drivable, but the PCM's program memory has a fault, which usually means the module needs reprogramming or replacement.
What P0605 means
The engine control module has detected a fault in its internal read-only memory (ROM) — the stored program itself. This usually means the PCM software is corrupted or the module is failing.
Symptoms
- Check engine light is on
- Possible running problems
- Multiple codes may appear
- Possible no-start
Common causes
- most common: Faulty engine control module (PCM)
- common: Failed or corrupted software update
- less common: Low battery voltage
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Reprogram (reflash) the engine control module | Mechanic | $100–300 |
| Replace the engine control module | Mechanic | $500–1500 |
Frequently asked questions
Can I drive with a P0605 code?
Sometimes, but the PCM may fail. Get it reprogrammed or replaced soon.
What is the most common cause of P0605?
A faulty engine control module or corrupted software.
How much does it cost to fix a P0605?
Reprogramming is $100–$300; a replacement PCM is $500–$1,500.
Related codes
P0601
P0601 Code: Internal Control Module Memory Check Sum Error
P0604P0604 Code: Internal Control Module Random Access Memory (RAM) Error
P0606P0606 Code: ECM/PCM Processor Fault
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.