B2042 Engine Trouble Code
What is B2042?
B2042 indicates potential catalytic converter failure. If completely failed, your vehicle may not run properly and fuel economy will suffer significantly. Average replacement cost is $2,000–$2,140. This repair requires professional service and should not be delayed.
Code Information
| Code Type: | OBD-II Body (B) Trouble Code |
| System: | Body |
| Code: | B2042 |
B2042 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
B2042 Code Structure
Understanding what each digit means in the B2042 body trouble code:
| B | 2 | 0 | 4 | 2 |
|---|---|---|---|---|
| Body Code | Fuel And Air Metering (Injector Circuit Malfunctions Only) | Ambient Air Temperature Sensor Circuit Low | Injection Pump Fuel Metering Control 'B' High | Glow Plug/Heater Circuit 'A' Malfunction |
How to Fix B2042
Diagnostic Steps:
The catalytic converter has oxygen sensors before and after it. When warm and in closed-loop mode, the upstream O2 sensor reading should fluctuate, while downstream should remain steady.
Repair Solution:
Power steering pressure switch monitors system operation. If pressure changes are not detected after calibrated speed transitions, this DTC sets. Verify PSP switch operation and check for circuit opens or shorts.
Technical Notes:
B2042 DTCs can be triggered by upstream issues. For example, a dirty MAF sensor may cause incorrect fuel-trim adjustments, leading oxygen sensors to report mixture problems. Address root causes first.
B2042 Description
B2042 engine trouble code is related to Glow Plug/Heater Circuit 'A' Malfunction.
Main Cause
The primary reason for B2042 OBD-II Engine Trouble Code is: Ambient Air Temperature Sensor Circuit Low.