Faulty catalyst temperature sensor on bank 2; Damaged, chafed or heat-affected wiring to the sensor; Corroded, loose or contaminated connector at the sensor or control unit; Exhaust leak near the sensor affecting its readings or causing damage to the sensor; Open circuit or short to earth or supply in the sensor circuit; Engine control unit fault or outdated software, only where the manufacturer lists it as a known cause.

P0435

Catalyst Temperature Sensor Circuit Bank 2 Sensor 1.

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
35: FaultThe specific fault in that area

What it means

P0435 means the engine control unit has detected a fault in the circuit of the catalyst temperature sensor on bank 2, sensor 1 (the sensor position nearest the engine, before or at the inlet of the catalyst). The control unit saw a signal outside the expected range, no signal, or a reading that does not make sense for the operating conditions. Not all vehicles have catalyst temperature sensors, and the exact sensor location and strategy vary by model and engine.

Symptoms

Engine management light on
Possible reduced power or limp mode on some models if the temperature model is used for component protection
Other catalyst or exhaust temperature codes stored alongside it
Failed emissions test or readiness monitors not completing
Often no noticeable change in driveability

Possible causes

Faulty catalyst temperature sensor on bank 2likely
Damaged, chafed or heat-affected wiring to the sensorlikely
Corroded, loose or contaminated connector at the sensor or control unitlikely
Exhaust leak near the sensor affecting its readings or causing damage to the sensorpossible
Open circuit or short to earth or supply in the sensor circuitpossible
Engine control unit fault or outdated software, only where the manufacturer lists it as a known causerare

How to diagnose

Read all stored and pending codes and record the freeze frame data, noting engine temperature, load and mileage at the time it set
Check for related codes such as other catalyst, exhaust temperature or oxygen sensor faults, which may point to a shared wiring or power issue
Confirm which sensor is bank 2, sensor 1 on this engine using manufacturer data, as the layout varies by model
Visually inspect the sensor, wiring and connector for heat damage, chafing, corrosion, water ingress and exhaust leaks
Watch the live temperature reading with the engine cold, then warm, and check it rises smoothly and plausibly compared with the other bank
Check the sensor circuit for supply, earth and signal, and for resistance and continuity against manufacturer specifications
Check for any applicable technical bulletins or software updates for the vehicle
Clear the code after repair and road test to confirm it does not return

How to fix

Replace the faulty bank 2 catalyst temperature sensor
Repair or replace damaged wiring, with proper heat-resistant routing and securing
Clean, repair or replace corroded or damaged connectors and terminals
Repair any exhaust leak near the sensor
Apply a manufacturer-issued control unit software update only if the bulletin lists it as the fix for this fault

Can I keep driving?

Low severity

The car can usually be driven while you book it in, as the fault is in a monitoring circuit. If the car goes into limp mode or shows other exhaust or catalyst warnings, have it checked promptly to avoid possible catalyst damage.

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