OBD Guide

P1139

Long Term Fuel Trim Add. Fuel B2 System Too Rich

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Increased fuel consumption
  • Black smoke from the exhaust pipe
  • Unstable engine operation
  • Power Loss
  • Gasoline smell from exhaust

Causes

  • Oxygen sensor malfunction (Bank 2)
  • Fuel leak in the fuel system
  • Dirty or faulty injectors
  • Problems with the EVAP system
  • Malfunction of the mass air flow sensor (MAF)

How to Fix

  1. Check oxygen sensor readings
  2. Inspect the fuel system for leaks
  3. Check the condition and operation of the fuel injectors
  4. Diagnose the EVAP system for faults
  5. Check the performance of the mass air flow sensor

Related codes

Error P1139 by Vehicle Brand