B3403 Engine Trouble Code
What is B3403?
B3403 code can indicate a faulty oxygen sensor, which may eventually damage the catalytic converter (repair cost: $2,000–$2,200). Professional diagnosis costs around $200–$210. Oxygen sensors are often straightforward to replace — check your owner's manual for location and instructions. This issue should be addressed promptly to prevent further damage.
Code Information
| Code Type: | OBD-II Body (B) Trouble Code |
| System: | Body |
| Code: | B3403 |
B3403 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
B3403 Code Structure
Understanding what each digit means in the B3403 body trouble code:
| B | 3 | 4 | 0 | 3 |
|---|---|---|---|---|
| Body Code | Ignition System Or Misfire | O2 Sensor Heater Circuit Malfunction | Cold Start Injector 1 Malfunction | Exhaust Gas Recirculation Sensor B Circuit High |
How to Fix B3403
Diagnostic Steps:
Regarding B3403, carefully inspect the wire harness near the intake manifold bracket, best accessed from below near the oil filter. Look for chafing, pinching, or damaged insulation.
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 B3403, verify VCT solenoid operation. Look for stuck or sticking valves caused by contamination. Consult vehicle-specific repair manual for proper component testing procedures.
B3403 Description
B3403 engine trouble code is related to Exhaust Gas Recirculation Sensor B Circuit High.
Main Cause
The primary reason for B3403 OBD-II Engine Trouble Code is: O2 Sensor Heater Circuit Malfunction.