OBD-II code · Network
U0603 Lost Communication With Fuel Pressure Sensor A
The vehicle bus reports loss of communication with smart fuel pressure sensor A (typically common-rail or low-pressure side). The ECM loses its actual rail-pressure feedback for closed-loop control.
Is it safe to drive with U0603?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyBus wiring open or shorted
- PossibleModule without power or ground
- PossibleModule failed
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Fuel Pressure Sensor A, Vehicle Bus Wiring
Related codes
- U0604Lost Communication With Fuel Pressure Sensor B
- U0600Internal Control Module Memory Reset
- U0601Internal Control Module Software Incompatibility
- U0602Lost Communication With Particulate Filter Pressure Sensor B
- U0605Lost Communication With A/C Refrigerant Sensor A
- U0606Lost Communication With Throttle/Pedal Position Sensor/Switch A
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.