P042B

Symptoms

• Check Engine light is on
• Possible reduction in catalytic converter efficiency
• Increased harmful emissions
• In most cases, ride quality is not affected
• Emergency mode with power limitation possible

Causes

• Mechanically faulty or dirty temperature sensor
• Damage or “poisoning” of the catalytic converter
• Lost contact in the sensor connector (poor contact without complete breakage)
• A heat shield that slides and isolates the sensor from the flow of gases
• Real inefficiency of bank 1 catalyst
• Carbon or oil on the sensor

How to Fix

1. Read all codes and sensor data in real time while the engine warms up
2. Compare sensor 2 readings with expected temperature profile
3. Check the sensor connector and wiring for poor contact.
4. Inspect the catalyst heat shields for shear or damage.
5. Replace bank 1 temperature sensor, sensor 2
6. Check catalyst efficiency (codes P0430 and P0432)
7. Reset codes and take a test drive

Related codes

Error P042B by Vehicle Brand