What it means
A general electrical fault on the catalyst temperature sensor at bank 2 sensor 1.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bank 2 Sensor 1 is the catalyst-temperature sensor on the Bank 2 side at position 1; it reports temperature information to the control module. P0435 sets when the module detects an electrical fault in that sensor circuit, rather than a particular temperature reading.
Common causes
Most likely first.
- Catalyst temperature sensor failure
- Open or short in the sensor wiring
- Corroded or loose sensor connector
- Fault in the control module
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
How to diagnose it
- Read freeze-frame and live data for Bank 2 Sensor 1 to see whether its reported temperature is missing or implausible when the fault sets.
- Inspect the Bank 2 Sensor 1 connector and nearby harness for exhaust heat damage, corrosion, loose pins, or chafing.
- Check the sensor circuit for opens, shorts, and poor connections using the manufacturer's wiring information.
- Test the Bank 2 Sensor 1 signal and any required supply or ground at the connector according to the manufacturer's procedure.
- If wiring and connections pass, test the catalyst-temperature sensor itself; consider a control-module fault only after the circuit and sensor are verified.
Common fixes
- Reconnect or clean a loose or corroded Bank 2 Sensor 1 connector.
- Repair damaged or open wiring in the Bank 2 Sensor 1 circuit.
- Replace Bank 2 Sensor 1 if its electrical output fails the specified test.
- Repair or replace a control module only if circuit and sensor tests confirm a module fault.
Can I keep driving?
Gentle driving is usually possible if the engine runs normally, but catalyst monitoring may be unreliable and emissions inspection can fail. Avoid prolonged hard driving if the exhaust smells strongly of sulfur, and repair the sensor-circuit fault so catalyst protection and monitoring can work correctly.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.