P0425: Catalyst Temperature Sensor Circuit Bank 1 Sensor 1
What to do
Usually driveable with no symptom beyond the warning light.
What this code means
A general circuit fault on the bank 1 catalyst temperature sensor. Where fitted, this sensor lets the module protect the converter — an over-temperature reading can trigger fuelling changes or a power reduction before the substrate is damaged — and grade its warm-up behaviour.
The sensor lives directly in exhaust heat, so its wiring suffers more than most. Inspect the harness where it runs along the exhaust before replacing the sensor.
Likely causes
Start here
- Faulty catalyst temperature sensor · moderate
- Damaged wiring harness near exhaust heat · moderate
- Corroded or loose connector · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about P0425.