OBD Guide

P1177

O2 Correction Behind Catalyst B1 Limit Attained

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$33–167 (est.)

Symptoms

  • Increased fuel consumption
  • Check Engine Light Is On
  • Reduced engine power
  • Increased level of harmful emissions
  • Unstable engine operation at idle

Causes

  • Malfunction of the catalytic converter
  • Leaks in the exhaust system
  • Problems with the rear oxygen sensor
  • Front oxygen sensor malfunctions
  • Problems with the fuel system (injectors, pressure regulator)

How to Fix

  1. Check the condition of the catalytic converter
  2. Inspect the exhaust system for leaks
  3. Check the functionality of the oxygen sensors
  4. Check the condition of the fuel injectors and pressure regulator
  5. Scan the system for other errors

Related codes

Error P1177 by Vehicle Brand