P0428

Catalyst Temperature Sensor Circuit High Bank 1 Sensor 1

Q: Is it safe to drive with P0428?

Yes — it's a monitoring-sensor fault, not a driving hazard, though it may fail emissions and won't complete the catalyst monitor.

Q: Can I just clear P0428?

It returns once the ECM rechecks the circuit; repair the sensor or wiring first — don't replace the converter on this code alone.

Catalyst / emissions Generic OBD-II Medium

What it means

P0428 means the catalyst temperature sensor on bank 1 (sensor 1) is reading abnormally high — usually an open circuit or a signal above its normal range. This sensor lets the ECM monitor catalytic-converter temperature. It's a sensor-circuit fault: the problem is normally the sensor or its wiring, not the converter itself.

Medium

Can I keep driving? Driveable — this is a catalyst monitoring sensor, so the car runs normally; expect a warning light and a possible emissions-test failure rather than a breakdown.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Likely failed emissions test
Little or no change in driveability
Catalyst monitor may not complete readiness

Common causes

Most likely first

Faulty catalyst temperature sensorLikely
Open circuit or short to voltage in the sensor wiringCommon
Loose or corroded connectorCommon
Faulty ECM (rare)Less often

How to diagnose & fix

Work through it in order

Read freeze-frame data and note the sensor's reported temperature.
Inspect the sensor connector and wiring for opens or shorts to power.
Measure the sensor's resistance and compare it to its temperature spec.
Replace the catalyst temperature sensor if it reads out of range.
Only investigate the converter itself once the sensor circuit is confirmed good. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0428?+

Yes — it's a monitoring-sensor fault, not a driving hazard, though it may fail emissions and won't complete the catalyst monitor.

Can I just clear P0428?+

It returns once the ECM rechecks the circuit; repair the sensor or wiring first — don't replace the converter on this code alone.

Read & clear P0428 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX