Faulty or drifting catalyst temperature sensor 1 or 2 on bank 2; Damaged, corroded or heat-affected wiring or connector to the bank 2 temperature sensors; Exhaust leak near the sensors, which skews the temperature readings; Sensor fitted in the wrong position, loose, or contaminated with soot or deposits; Degraded or failing catalyst on bank 2 that no longer heats as expected; Fault in the engine control unit or an outdated calibration, where the manufacturer lists it as a known cause.

P046B

Catalyst Temperature Sensor 1/2 Correlation Bank 2.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
4: AreaAuxiliary emission controls
6B: FaultThe specific fault in that area

What it means

P046B means the engine control unit found that the readings from catalyst temperature sensor 1 and sensor 2 on bank 2 do not agree as expected. These sensors sit before and after the catalyst, and the control unit compares them against each other and against its own temperature model. If the difference is outside the expected range, it sets the code. The exact sensor layout and strategy depend on the model and engine.

Symptoms

Engine warning light on
Reduced power or limp mode on some models
Poor fuel economy
Exhaust aftertreatment warnings or regeneration problems on some vehicles
Other exhaust temperature or catalyst efficiency codes stored alongside

Possible causes

Faulty or drifting catalyst temperature sensor 1 or 2 on bank 2likely
Damaged, corroded or heat-affected wiring or connector to the bank 2 temperature sensorslikely
Exhaust leak near the sensors, which skews the temperature readingspossible
Sensor fitted in the wrong position, loose, or contaminated with soot or depositspossible
Degraded or failing catalyst on bank 2 that no longer heats as expectedpossible
Fault in the engine control unit or an outdated calibration, where the manufacturer lists it as a known causerare

How to diagnose

Read all stored and pending codes and note any related exhaust temperature, catalyst or oxygen sensor codes.
Review freeze frame data to see engine load, speed and temperatures when the code set.
Inspect the bank 2 sensor wiring and connectors for heat damage, chafing, corrosion and water ingress.
Check the exhaust on bank 2 for leaks, damage or loose joints around the sensors and catalyst.
With live data, compare sensor 1 and sensor 2 temperatures on bank 2 from cold through to warm, and against bank 1 if fitted.
Check the sensor circuit for correct supply, ground and signal, following the manufacturer's wiring information for your model.
Check for sensor contamination or incorrect fitting, and assess catalyst condition using the manufacturer's procedure.
Check for software updates or technical bulletins that apply to this code on your model.

How to fix

Repair or replace damaged wiring or connectors on the bank 2 temperature sensor circuit.
Replace the faulty catalyst temperature sensor with a correct specification part.
Repair any exhaust leaks and refit the sensors correctly.
Replace the bank 2 catalyst if it is confirmed to be failing, after the root cause is fixed.
Apply a manufacturer calibration update only if a bulletin lists it as a fix for this fault.

Can I keep driving?

Medium severity

The car can usually be driven short-term, but get it checked soon as a continuing fault may affect emissions control and could lead to catalyst damage. If power is reduced or warnings escalate, limit driving.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.