P0426
Catalyst Temperature Sensor Circuit Range/Performance Bank 1 Sensor 1
Emissions / catalyst
Generic OBD-II
Medium
What it means
P0426 means the bank 1 catalyst temperature sensor is reporting a value that doesn't match expected conditions. This sensor monitors catalytic converter temperature. An out-of-range reading — usually from a failing sensor or wiring issue, and occasionally from a real exhaust over-temperature — sets the code, typically without any obvious change in how the car drives.
Medium
Can I keep driving? Safe to drive. This mainly affects emissions monitoring; there's usually no drivability problem, but it can fail an emissions test.
Common symptoms
What you'll notice
- Check-engine light on
- Often no noticeable change in how the vehicle drives
- May fail an emissions/readiness test
- Possible loss of power only if the ECM limits output to protect the catalyst
Common causes
Most likely first
- Faulty catalyst temperature sensor reading out of rangeLikely
- Damaged or corroded wiring in the sensor circuitCommon
- Loose or corroded connectorCommon
- Actual exhaust over-temperature (e.g. from a misfire) the sensor is correctly reportingLess often
- Failed ECM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and note the catalyst temperature being reported.
- Inspect the sensor connector and wiring for damage or corrosion.
- Compare the reading to actual conditions to see if the sensor or the exhaust is the problem.
- Rule out misfire or rich/lean codes that could genuinely overheat the catalyst.
- Replace the catalyst temperature sensor if it reads out of range. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0426?+
Generally yes. It's an emissions-monitoring fault, so plan to fix it before an emissions test. If it stems from an actual exhaust over-temperature, address that cause promptly.
Can I just clear P0426?+
It returns once the ECM again sees the sensor out of range. Repair the sensor or wiring first, then clear and re-test.
Related codes
Often seen with P0426
Read & clear P0426 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