U019D code meaning
Lost Communication With Direct Ozone Reduction Catalyst Temperature Sensor
Network system Generic code U01xx codes Check engine light
What U019D means
U019D concerns a temperature sensor at a direct ozone reduction (DOR) catalyst that reports over the network rather than a plain wire; the wired versions have P2567-P2571. A DOR catalyst is a coating on the radiator or A/C condenser that turns ozone in the passing air into oxygen, such as Engelhard's PremAir, first fitted by Volvo on the S80 and by Nissan on the Sentra CA. CARB grants an NMOG credit for it only with an OBD monitor, and 13 CCR 1968.2 (e)(14) sets the malfunction criteria; under LEV III the credit reaches 5 mg/mi. No manufacturer documents U019D publicly. Without sensor data the DOR monitor cannot run, so the credit is unsupported and a MIL is to be expected. Driving is unaffected. U049E is invalid data.
U019D at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U019D
- MIL on without noticeable driving fault
- DOR monitor shown as not complete
Common causes of U019D
- Most likelySensor connector at the radiator corroded or damaged by road debris
- PossibleSensor left unplugged or radiator replaced after front-end repair
- PossibleBus or supply line to the sensor broken
- Less likelyDOR temperature sensor faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Dor catalyst temp sensorCAN bus
What each part of U019D means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 9D | The exact fault in that area. |
What to do next
- Note U019D 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 U019D
What does U019D mean?
U019D means "Lost Communication With Direct Ozone Reduction Catalyst Temperature Sensor". U019D concerns a temperature sensor at a direct ozone reduction (DOR) catalyst that reports over the network rather than a plain wire; the wired versions have P2567-P2571. It is a generic code, so it means the same on every make.
Is it safe to drive with U019D?
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 U019D fail an emissions test?
Yes, it can. U019D 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 U019D to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. This is a job for a workshop.
Will U019D clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.