Direct Ozone Reduction Catalyst Efficiency Below Threshold
The P2577 code indicates that the direct ozone reduction (DOR) catalyst, typically located in the radiator or condenser, is not converting ozone into oxygen efficiently. This system is part of the vehicle's emissions control, and the code sets when the downstream sensor detects insufficient ozone reduction. Common causes include a failed DOR catalyst, exhaust leaks, or sensor malfunction.
01. Most Common Causes
- Faulty direct ozone reduction catalyst
- Exhaust leak before or after the catalyst
- Malfunctioning ozone sensor
- Damaged wiring or connectors to the sensor
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Failed emissions test
- Possible slight decrease in fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the DOR catalyst and exhaust system for damage or leaks.
Step 3: Test the ozone sensor signal using a scan tool or multimeter.
Step 4: Check wiring and connectors for corrosion or damage.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, it is generally safe to drive, but the vehicle may fail an emissions test and the Check Engine Light will remain on. Prompt diagnosis is recommended to prevent further issues.
How much does it cost to fix?▼
Costs vary from $50 for a sensor replacement to $150 for a new DOR catalyst, plus labor. Total can range $100-$400 depending on the part and labor rates.