U049E code meaning
Invalid Data Received From Direct Ozone Reduction Catalyst Temperature Sensor
Network system Generic code U04xx codes Check engine light
What U049E means
Direct ozone reduction (DOR) means a catalytic coating on the radiator, sold by BASF as PremAir, that turns ground-level ozone into oxygen while air flows through the core. CARB grants an emissions credit for it and, under section (e)(14) of 1968.2, wants OBD to watch the coating on cars that claim the credit; a temperature sensor on the radiator serves this purpose. U049E applies where that sensor reports over a data link and its messages arrive but fail plausibility. A hard-wired sensor instead uses P2567 to P2570. No manufacturer documents U049E publicly. U019D marks a sensor that has gone silent. The car drives normally; the result is a MIL, a suspended ozone catalyst check and possibly a failed inspection. Check wiring and the sensor before suspecting the radiator.
U049E at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of U049E
- Check engine light on without noticeable drivability change
- Emissions inspection failed or readiness not set
Common causes of U049E
- Most likelyRadiator temperature sensor electronics faulty
- PossibleDamaged connector or wiring near the radiator (impact, corrosion)
- PossibleReplacement radiator or sensor not matching the original DOR version
- Less likelySensor or engine controller software version not matching
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Dor catalyst temp sensor
What each part of U049E means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 9E | The exact fault in that area. |
What to do next
- Note U049E and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U049E
What does U049E mean?
U049E means "Invalid Data Received From Direct Ozone Reduction Catalyst Temperature Sensor". Direct ozone reduction (DOR) means a catalytic coating on the radiator, sold by BASF as PremAir, that turns ground-level ozone into oxygen while air flows through the core. It is a generic code, so it means the same on every make.
Is it safe to drive with U049E?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U049E fail an emissions test?
Yes, it can. U049E is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U049E to fix?
Difficulty: medium. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will U049E clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.