P1477 Engine Trouble Code
What is P1477?
When P1477 code appears, first check your gas cap. Pull over safely, ensure it is tight, and inspect for cracks. A loose or damaged gas cap affects fuel-system pressure and emissions. A replacement cap costs about $3–$10. This simple fix can resolve the code and improve fuel economy.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Code: | P1477 |
P1477 Symptoms
Check Engine Light
Illuminated dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration
Starting Problems
Difficulty starting the engine
P1477 Code Structure
Understanding what each digit means in the P1477 powertrain trouble code:
| P | 1 | 4 | 7 | 7 |
|---|---|---|---|---|
| Powertrain Code | Fuel And Air Metering | O2 Sensor Heater Circuit Malfunction | Cylinder 10 Contribution/Balance Fault | Shift/Timing Solenoid Malfunction |
How to Fix P1477
Diagnostic Steps:
Oxygen sensors measure exhaust gas oxygen content to optimise air-fuel ratio. This optimisation improves fuel economy and reduces emissions. Sensors degrade over time and require periodic replacement.
Repair Solution:
A/C pressure sensor monitors refrigerant pressure changes. DTC sets when pressure change falls outside calibration. Verify A/C system function, refrigerant charge, and electrical connections.
Technical Notes:
For P1477, verify VCT solenoid operation. Look for stuck or sticking valves caused by contamination. Consult vehicle-specific repair manual for proper component testing procedures.
P1477 Description
P1477 OBD-II Trouble Code: Additional Fan Relay Circuit Malfunction is one of the definitions for the P1477; however your vehicles manufacturer may have a different definition for the P1477 code. Please check below for your spe
Main Cause
The primary reason for P1477 OBD-II Engine Trouble Code is: O2 Sensor Heater Circuit Malfunction.