P1003
Fuel Composition Signals Message Counter Incorrect
Severity
⚠️ MediumCan you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)
Symptoms
- Unstable engine operation
- Increased fuel consumption
- Check Engine Light Illuminates
- Reduced engine power
- Problems starting the engine
Causes
- CAN bus break or damage
- Engine control module (ECU) malfunction
- Problems with fuel composition sensors
- Corrosion of contacts in the data transmission circuit
- Software error in control module
How to Fix
- Check the integrity of the CAN bus
- Diagnose the engine control module
- Check the condition of the fuel composition sensors
- Clean contacts in the data circuit
- Update ECU firmware