TorqueMech OBD Code Guide
P0231 - Fuel Pump Secondary Circuit Low
Fuel pump secondary feedback circuit is reading low.
Code first. Confirm symptoms and checks before pricing parts.
Read code pattern
Check likely system
Estimate after confirmation
Common Next Steps
Turn the code into the next check.
Test charging voltage
Measure alternator output and battery voltage under load.
Inspect serpentine belt
Check belt condition, tensioner travel, and pulley alignment.
Verify battery condition
Charge and load test before blaming the alternator or starter.
Related Inspection
Code Overview
Fuel pump secondary feedback circuit is reading low.
Common Causes
- Low supply voltage
- High resistance in the circuit
- Weak pump
- Wiring issue
Diagnostic Steps
- Load-test the battery and charging system
- Check voltage drop across the pump feed and ground
- Inspect relay and connector condition
Related OBD Codes
Browse nearby codes when systems overlap.
Next Steps
Move from code to checks, then estimate.