P1421
Cold Start Control
Severity
⚠️ MediumCan you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)
Symptoms
- Difficulty when starting the engine cold
- Unstable idle speed
- Increased fuel consumption
- Difficulties in engine operation during a cold start
- Check Engine Light Illuminates
Causes
- Coolant temperature sensor malfunction
- Problems with fuel injectors
- Fuel pressure regulator malfunction
- Problems with control system wiring or connectors
- Engine control unit malfunction
How to Fix
- Check the coolant temperature sensor and its circuit
- Diagnose the operation of fuel injectors
- Check fuel pressure regulator
- Inspect the wiring and connectors of the control system
- Test or reflash the engine control unit