What does P0604 mean?
This code means the engine or powertrain computer found a problem with itself or its communication.
Codes are a starting point. They tell you which test failed, not which part to replace. Check for other stored codes and fix those in a sensible order.
Symptoms
- Check engine light
- Possible no-start, stalling or limp mode
- Other codes stored at the same time
Common causes
- Low battery voltage during a self-test
- Bad module grounds or power feeds
- Software problem (fixed by an update)
- Internal module failure
How to diagnose P0604
- Check battery and charging voltage first.
- Check module power and ground circuits.
- Look up technical service bulletins for a software update.
- Only replace the module once power, grounds and software are ruled out.
How to fix it
- Repair power or ground
- Reprogram the module
- Replace and program the module
Estimated repair cost
Likely repairs for P0604 run from about $100 to $1,800, depending on the cause.
| Repair | Typical range (parts + labor) |
|---|---|
| Diagnostic fee (scan + testing) | $100 - $200 |
| Software update / reprogramming | $100 - $250 |
| Control module replace/program | $500 - $1,800 |
These are rough US estimates for an independent shop in 2026, based on typical parts prices and standard labor times. Dealers, big trucks, luxury brands and high-cost areas often run higher. They are not quotes. Use the repair cost estimator to adjust for your vehicle.
How serious is P0604?
High severity
Depends on symptoms. If the engine stalls or goes into limp mode, have it towed.
P0604 FAQ
What does P0604 mean?
P0604 stands for "Internal Control Module Random Access Memory (RAM) Error". This code means the engine or powertrain computer found a problem with itself or its communication.
Can I drive with a P0604 code?
Depends on symptoms. If the engine stalls or goes into limp mode, have it towed.
How much does it cost to fix P0604?
It depends on the cause. The likely repairs for P0604 range from about $100 to $1,800 at an independent shop in the US, plus a diagnostic fee of roughly $100-$200. These are rough estimates; dealer prices and some vehicles run higher.
What is the most common cause of P0604?
The most common causes are: low battery voltage during a self-test; bad module grounds or power feeds; software problem (fixed by an update).