P0605 — Internal Control Module Read Only Memory (RAM) Error
Drivable short-term, but fix now to avoid damage.
What P0605 means
This code means the engine computer found a fault in its internal Random Access Memory (RAM), the working memory it uses to run calculations while the engine is on. This is usually an internal hardware problem within the PCM itself, though poor power or ground connections can also trigger it. Repairs often involve reprogramming the module and, if that fails, replacing the computer.
Common symptoms
- Check engine light is on
- Engine stalls or runs erratically
- Hard starting or no start
- Reduced power or limp mode
- Other warning lights may come on
Common causes
- Internal RAM hardware fault in the control module
- Corroded or loose ground connections
- Low or unstable battery voltage
- Water or moisture damage inside the computer
- Damaged wiring or connectors to the PCM
Typical repair cost
$150 – $1200
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0605 code?
It's risky. Because the computer's working memory is failing, the engine could stall or refuse to start without warning. Drive only the short distance needed to get it diagnosed, and avoid long trips.
How much does it cost to fix a P0605 code?
If reprogramming and wiring repairs solve it, you might spend $150 to $350. If the computer must be replaced and programmed, expect roughly $800 to $1,200 or more depending on the vehicle.
Is a P0605 code serious?
Yes. A RAM fault points to the heart of the engine's computer, and it can cause stalling, no-starts, or unpredictable behavior. It should be diagnosed and repaired promptly.
Does P0605 always mean I need a new computer?
Not always. Sometimes it's caused by bad grounds, low voltage, or a glitch that clears after reprogramming. But if the fault is truly inside the chip, the PCM usually needs to be replaced.