Damaged, corroded or loose wiring or connector at the Bank 2 catalyst temperature sensor; Failed catalyst temperature sensor (internal open circuit or fault); Signal wire shorted to a voltage supply or chafed against another live wire; Wiring damaged by exhaust heat, road debris or previous repair work; Fault in the engine control unit sensor input or its reference supply; Outdated control unit software on certain models, if a manufacturer bulletin confirms it.

P043D

Catalyst Temperature Sensor Circuit High Bank 2 Sensor 2.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
4: AreaAuxiliary emission controls
3D: FaultThe specific fault in that area

What it means

P043D is the generic code for a high input fault in the catalyst temperature sensor circuit on Bank 2, Sensor 2, which is the sensor monitoring the downstream part of the catalytic converter. The engine control unit saw the sensor signal voltage above the expected range, which usually points to an open circuit, a short to voltage or a failed sensor. The control unit can no longer trust the catalyst temperature reading, so it may limit related monitoring.

Symptoms

Engine management light on
No obvious change in how the car drives in many cases
Catalyst monitor or other emissions readiness tests not completing
Failed emissions test or MOT
Possible related catalyst efficiency or temperature codes stored

Possible causes

Damaged, corroded or loose wiring or connector at the Bank 2 catalyst temperature sensorlikely
Failed catalyst temperature sensor (internal open circuit or fault)likely
Signal wire shorted to a voltage supply or chafed against another live wirepossible
Wiring damaged by exhaust heat, road debris or previous repair workpossible
Fault in the engine control unit sensor input or its reference supplyrare
Outdated control unit software on certain models, if a manufacturer bulletin confirms itrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, then check for other catalyst, exhaust temperature or sensor supply codes.
Confirm which side is Bank 2 for this engine, and whether the car actually fits a catalyst temperature sensor there, as this varies by model and engine.
Inspect the sensor, its wiring and connector along the exhaust run for heat damage, chafing, corrosion, water ingress and bent or pushed-out pins.
With the engine cold and then warm, view the live catalyst temperature value and check it is plausible and changes smoothly rather than sitting at its maximum.
Unplug the sensor and check the signal and reference voltages at the harness against the manufacturer's data for your model.
Check the wiring for continuity and for shorts to voltage or to ground between the sensor and the control unit.
Measure the sensor's resistance or output against the specification for your model, and compare with a known-good reading if available.
Check for any manufacturer software updates or bulletins relating to this code before replacing the control unit.

How to fix

Repair or replace damaged wiring and renew corroded or damaged connector terminals.
Replace the Bank 2 catalyst temperature sensor if it is out of specification.
Repair any short to voltage in the signal circuit and secure the harness away from heat and sharp edges.
Fit a control unit software update only if the manufacturer lists it as a known fix for this fault.
Clear the code after the repair and complete a drive cycle to confirm it does not return and the monitors run.

Can I keep driving?

Low severity

The car can usually be driven normally, but book it in soon as it may fail an emissions test and can hide a problem with catalyst monitoring. If you notice reduced power or other warning lights, have it checked sooner.

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