What Does P2577 Mean?
The PCM has determined that the Direct Ozone Reduction catalyst is not performing efficiently enough to reduce ozone to acceptable levels. This indicates actual catalyst degradation or failure rather than a sensor issue.
Common Causes
50%
Deteriorated or contaminated ozone reduction catalyst
20%
Engine running rich causing catalyst overheating and damage
15%
Engine oil or coolant contamination of catalyst
10%
Exhaust leaks upstream of catalyst affecting efficiency
5%
Physical damage to catalyst substrate
Diagnostic Steps
1
Step 1: Verify proper engine operation and check for other DTCs indicating fuel trim or misfire issues
2
Step 2: Check exhaust system for leaks upstream and downstream of the ozone catalyst
3
Step 3: Measure catalyst inlet and outlet temperatures to assess thermal efficiency
4
Step 4: Inspect catalyst for physical damage, rattling, or signs of overheating
5
Step 5: Perform exhaust backpressure test to rule out plugged catalyst before replacement
Estimated Repair Cost
$800 - $2,500
Parts + labor, varies by vehicle and location
The PCM has determined that the Direct Ozone Reduction catalyst is not performing efficiently enough to reduce ozone to acceptable levels. This indicates actual catalyst degradation or failure rather than a sensor issue.
The most common cause of P2577 (Direct Ozone Reduction Catalyst Efficiency Below Threshold) is: Deteriorated or contaminated ozone reduction catalyst
Typical repair costs for P2577 range from $800 to $2,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive but repair soon. Increased emissions output and potential for emissions test failure.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2577 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Emissions Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
