P0604 — Internal Control Module Keep Alive Memory (KAM) Error
Drivable short-term, but fix now to avoid damage.
What P0604 means
This code means the engine computer detected an error in its Keep Alive Memory (KAM), the part that retains learned data like fuel trims even when the engine is off. It's often caused by a weak battery, bad ground connections, or a failing computer chip. Fixes can be as simple as clearing the code and repairing wiring, or as involved as reprogramming or replacing the PCM.
Common symptoms
- Check engine light is on
- Rough idle or hesitation
- Poor fuel economy
- Engine adjustments feel reset or sluggish
- Occasional stalling or hard starting
Common causes
- Weak or failing battery
- Corroded or loose ground connections
- Recent battery disconnect that wiped memory
- Internal fault in the control module
- Damaged wiring or poor power supply to the PCM
Typical repair cost
$100 – $1000
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0604 code?
For short trips, usually yes, but you shouldn't rely on it long term. The car may run rougher and use more fuel since the computer lost its learned settings. Have it checked soon to confirm whether it's a battery, wiring, or computer issue.
How much does it cost to fix a P0604 code?
If it's a weak battery or bad ground, the repair may only be $100 to $250. If the computer needs reprogramming or replacement, costs can rise to $700 to $1,000 depending on the vehicle and labor.
Is a P0604 code serious?
It's moderately serious. The car may still drive, but the engine computer isn't storing its data correctly, which can affect performance and reliability. Treat it as something to fix soon rather than ignore.
Will a P0604 code go away on its own?
Sometimes clearing the code and driving fixes a one-time glitch, especially after a battery change. But if it keeps returning, there's a real fault in the memory, wiring, or battery that needs to be repaired.