P042B

Catalyst Temperature Sensor Circuit Range/Performance

Moderate severity

Catalyst temperature sensor at bank 1 sensor 2 reads in range but plausibility check fails — slow response or stuck reading.

Common causes

Sensor drift
One of the most commonly reported causes for this code — check this first.
high
Typical part cost: $70-550
Sensor element aged beyond calibration window
Less common, but worth ruling out after the more likely causes.
low
Typical part cost: $70-550
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First things to check

1Confirm the code with a scan tool and check for additional related codes.
2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.

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Related codes

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Frequently asked questions

What does P042B mean?

P042B means "Catalyst Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 2)". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.

What are the most common causes of P042B?

sensor drift; sensor element aged beyond calibration window; sensor mounting loose - signal damping — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.

Can I keep driving with this code?

The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.

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