B0903 Engine Trouble Code
What is B0903?
When B0903 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 Body (B) Trouble Code |
| System: | Body |
| Code: | B0903 |
B0903 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
B0903 Code Structure
Understanding what each digit means in the B0903 body trouble code:
| B | 0 | 9 | 0 | 3 |
|---|---|---|---|---|
| Body Code | Intake Valve Control Solenoid Circuit Low | Injector Circuit Malfunction - Cylinders | Cold Start Injector 1 Malfunction | Exhaust Gas Recirculation Sensor B Circuit High |
How to Fix B0903
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 B0903 DTC. Consult your vehicle service manual for proper diagnostic procedures, possible causes, and required testing before replacement.
B0903 Description
B0903 engine trouble code is related to Exhaust Gas Recirculation Sensor B Circuit High.
Main Cause
The primary reason for B0903 OBD-II Engine Trouble Code is: Injector Circuit Malfunction - Cylinders.