P0606 means Control Module Processor. The engine computer has detected an internal fault in its own processor or memory. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0606 means
Modern vehicles have many control modules that share information over a network, usually called the CAN bus. Codes starting with U mean a module has stopped hearing another one, and voltage and processor codes mean a module is not getting clean power or has an internal fault. Low battery voltage, poor grounds, blown fuses and damaged wiring cause many of these codes, so test the battery and charging system first.
P0606 symptoms
- Check engine light
- Stalling, no-start or reduced power on some vehicles
- Erratic shifting or several warning lights
Common causes of P0606
- Internal engine computer failure
- Poor power supply or grounds to the module
- Software that needs an update
- Water damage to the module
How to diagnose P0606
- Check battery voltage, module power and grounds first
- Check for software updates or technical service bulletins
- Replace or reprogram the module only after power and grounds test good
Can you drive with P0606?
It depends on the symptoms; if the engine stalls or enters limp mode, drive only to a repair shop.
P0606 tips
Before condemning the engine computer, check every power and ground circuit to the module and look for available software updates; module processor codes are sometimes caused by low voltage or fixed by reprogramming. A replacement module usually needs programming to the vehicle.
Will P0606 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0606 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0562 | System Voltage Low |
| U0100 | Lost Communication With ECM/PCM A |
| U0073 | Control Module Communication Bus A Off |
Guides that help
When it is more than a sensor
Voltage and network codes come from wiring, the battery, the charging system or a module, not from engine or transmission wear. If a lost-communication code has left the transmission in limp mode, rule out the module and wiring before deciding the unit has failed, and see our transmissions only if testing confirms internal damage.
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