Insufficient Coolant Temperature for Closed Loop Fuel Control
2001-2001 Cadillac DeVille 4.6L V8 Northstar
The 2001 Cadillac DeVille is equipped with a 4.6L V8 engine. Below you'll find detailed p0125 diagnostic code information including labor time estimates, cost ranges, and technician notes specific to this engine configuration.
Description
The engine is not reaching normal operating temperature quickly enough for the PCM to enter closed-loop fuel control.
Symptoms
- Check Engine Light
- Poor fuel economy
- Extended warmup time
- Rich exhaust smell
Common Causes
- Stuck-open thermostat
- Faulty ECT sensor
- Cooling fan running constantly
- Low coolant level
Diagnostic Steps
- Monitor ECT warmup time (should reach 160°F within 5-10 min)
- Test thermostat
- Check cooling fan operation
- Test ECT sensor
Repair Notes
Replace thermostat. Most common cause.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P0125 on Other Vehicles
Common Questions
What does code P0125 mean on a 2001-2001 Cadillac DeVille?
P0125 stands for "Insufficient Coolant Temperature for Closed Loop Fuel Control". The engine is not reaching normal operating temperature quickly enough for the PCM to enter closed-loop fuel control.
What are the symptoms of P0125 on a Cadillac DeVille?
Common symptoms of P0125 include: Check Engine Light, Poor fuel economy, Extended warmup time, Rich exhaust smell.
What causes P0125 on a 2001-2001 Cadillac DeVille?
Common causes of P0125 include: Stuck-open thermostat, Faulty ECT sensor, Cooling fan running constantly, Low coolant level.
Last updated: March 2026