C0804 Engine Trouble Code
What is C0804?
When C0804 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 Chassis (C) Trouble Code |
| System: | Chassis |
| Code: | C0804 |
C0804 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
C0804 Code Structure
Understanding what each digit means in the C0804 chassis trouble code:
| C | 0 | 8 | 0 | 4 |
|---|---|---|---|---|
| Chassis Code | Intake Valve Control Solenoid Circuit Low | Engine Oil Temperature Sensor Malfunction | Cold Start Injector 1 Malfunction | Timing Reference High Resolution Signal A Too Many Pulses |
How to Fix C0804
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:
Disconnected, dirty, or fouled spark plugs commonly prevent proper engine operation. Replace spark plugs every season or 25 hours. Verify proper spark plug gap. If plugs are good, check ignition components: spark plug wires, coils, and ignition module.
Technical Notes:
Parts or components should not be replaced based solely on C0804 DTC. Consult your vehicle service manual for proper diagnostic procedures, possible causes, and required testing before replacement.
C0804 Description
C0804 engine trouble code is related to Timing Reference High Resolution Signal A Too Many Pulses.
Main Cause
The primary reason for C0804 OBD-II Engine Trouble Code is: Engine Oil Temperature Sensor Malfunction.