P2574 Direct Ozone Reduction Catalyst Deterioration Sensor Circuit Low

P2574 is set when the deterioration sensor circuit of a direct ozone reduction (DOR) catalyst reads below its valid range, the usual signature of a short to ground or a failed sensor pulling the line down. No manufacturer documents P2574 publicly. The nearest documented analogue is P2569 on VW's 2.0 L TSI models, where the 2014 Tiguan book attributes a grounded LIN line of the radiator sensor to that code. A DOR catalyst only cleans the ambient air flowing through the radiator, so engine output, cooling and fuel use stay the same; the consequence is a warning lamp and possibly a failed OBD inspection. P2575 is the opposite fault, P2572 the general circuit code.

Likely causes

Symptoms

• Check engine light on
• Car drives and cools as before

Repair estimate

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

Parts involved

Related codes

References: law.cornell.edu, static.nhtsa.gov.