P042D
Catalyst Temperature Sensor Circuit High Bank 1 Sensor 2
Catalyst temperature sensor (emissions)
Generic OBD-II
Medium
What it means
P042D means the bank 1, sensor 2 catalyst temperature sensor circuit is reading high — usually an open circuit or a short to voltage. This sensor lets the ECM monitor converter temperature; a high, out-of-range reading sets the light but generally doesn't change how the engine starts or drives.
Medium
Can I keep driving? Safe to drive — this is a sensor-circuit fault that mainly turns on the warning light and affects emissions monitoring, not how the car runs.
Common symptoms
What you'll notice
- Check-engine light on
- Emissions readiness monitor may not complete
- Engine otherwise starts and runs normally
Common causes
Most likely first
- Sensor wiring open or shorted to voltageLikely
- Faulty catalyst temperature sensor (bank 1, sensor 2)Common
- Poor or corroded connectorCommon
- ECM fault (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the sensor connector and wiring for an open or a short to voltage.
- Measure the sensor's resistance/signal against temperature.
- Replace the temperature sensor if it is out of spec.
- Repair the wiring or connector as needed.
- Clear the code and re-test.
FAQ
Quick answers
Is it safe to drive with P042D?+
Yes — it's a monitoring-sensor fault, so fix it to clear the light and pass emissions.
Can I just clear P042D?+
You can, but it returns until the sensor circuit is repaired.
Related codes
Often seen with P042D
Read & clear P042D yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX