Faulty catalyst temperature sensor on bank 2 (either sensor 1 or sensor 2).; Damaged, corroded, or shorted wiring in the sensor circuit.; Poor electrical connection at the sensor connector.; Exhaust leaks before or near the sensors, causing false temperature readings.; A failing catalytic converter on bank 2 that alters the temperature profile.; ECM software calibration issues or internal ECM faults (less common).

DTC codes / P04xx · Auxiliary emission controls / P046B

P046BCatalyst Temperature Sensor 1/2 Correlation Bank 2

Q: What does code P046B mean?

Catalyst Temperature Sensor 1/2 Correlation Bank 2. P046B is a generic powertrain code indicating that the engine control module (ECM) has detected a correlation error between the two catalyst temperature sensors on bank 2. The ECM compares the temperature readings from the pre-catalyst and post-catalyst sensors and expects them to follow a predictable relationship; when the signals deviate beyond a calibrated threshold, it sets this code.

P046B is a generic powertrain code indicating that the engine control module (ECM) has detected a correlation error between the two catalyst temperature sensors on bank 2. The ECM compares the temperature readings from the pre-catalyst and post-catalyst sensors and expects them to follow a predictable relationship; when the signals deviate beyond a calibrated threshold, it sets this code.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms.
Reduced engine performance or power, especially under load.
Decreased fuel economy due to the ECM entering a protective mode.
In rare cases, a slight sulfur or rotten egg smell from the exhaust.
Intermittent rough running or hesitation if the fault affects fuel control.
Failed emissions inspection due to the stored code.

Common causes, most likely first

Faulty catalyst temperature sensor on bank 2 (either sensor 1 or sensor 2).
Damaged, corroded, or shorted wiring in the sensor circuit.
Poor electrical connection at the sensor connector.
Exhaust leaks before or near the sensors, causing false temperature readings.
A failing catalytic converter on bank 2 that alters the temperature profile.
ECM software calibration issues or internal ECM faults (less common).

How to diagnose and fix it

Perform a visual inspection of the bank 2 catalyst temperature sensors and their wiring for damage, corrosion, or loose connectors.
Use a scan tool to read live data from both catalyst temperature sensors on bank 2 and compare their readings during warm-up and steady driving.
Check for exhaust leaks around the sensors and repair any leaks found.
Test the sensor circuits with a multimeter for continuity, short circuits, and proper reference voltage according to the manufacturer's specifications.
If a sensor is suspect, swap it with a known-good sensor from the same bank (if accessible) to see if the code follows the sensor.
Replace the faulty catalyst temperature sensor if testing confirms it is out of specification.
Clear the code and perform a drive cycle to verify the repair; if the code returns, further diagnose the catalytic converter or ECM.

Diagnosing P046B Without Throwing Parts

A common mistake is replacing the catalytic converter immediately, but the code often stems from a failing temperature sensor or wiring issue that costs far less to fix.
The ECM may set this code due to a lazy sensor that responds slowly to temperature changes, which may not be obvious from static resistance checks alone.
Exhaust leaks upstream of the sensors can cause temperature correlation errors by allowing outside air to affect readings, so always inspect the exhaust system first.
On some vehicles, a weak battery or charging system issue can cause voltage drops that affect sensor signals and trigger false correlation codes.
After repairs, the ECM may require a specific drive cycle to relearn the catalyst temperature profile; simply clearing the code may not be enough to prevent recurrence.

Can I keep driving with P046B?

You can generally continue driving with this code, but avoid aggressive acceleration or heavy loads until it is diagnosed. Prolonged driving with a faulty catalyst temperature sensor may lead to increased emissions and potential damage to the catalytic converter, so schedule service soon.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.