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U019D Lost Communication With Direct Ozone Reduction Catalyst Temperature Sensor

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

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.

Likely causes

Sensor connector at the radiator corroded or damaged by road debris
Sensor left unplugged or radiator replaced after front-end repair
Bus or supply line to the sensor broken
DOR temperature sensor faulty

Symptoms

  • MIL on without noticeable driving fault
  • DOR monitor shown as not complete

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–400
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

dor catalyst temp sensorcan bus

Related codes

P2567P2568P2572U049E

References: law.cornell.edu, ww2.arb.ca.gov, saemobilus.sae.org, dieselnet.com.