OBD Guide

P1138

Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich

P1138 is an OBD-II diagnostic trouble code meaning: Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich. Common causes: malfunction of the oxygen sensor bank 1 sensor 2, open or short circuit in the sensor circuit. Estimated repair cost: $28–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$28–89 (est.)

Symptoms

  • Increased fuel consumption
  • Unstable engine operation at idle
  • Check Engine light comes on
  • Reduced engine power
  • Black smoke from the exhaust pipe

Causes

  • Malfunction of the oxygen sensor bank 1 sensor 2
  • Open or short circuit in the sensor circuit
  • Fuel system problems (mixture too rich)
  • Sensor contamination due to oil or coolant leak
  • Malfunction of the catalytic converter

How to Fix

  1. Check the condition of the oxygen sensor bank 1 sensor 2
  2. Check the continuity of the sensor circuit and connectors
  3. Check the fuel system for leaks
  4. Clean or replace the oxygen sensor
  5. Check the condition of the catalytic converter

Related codes

Error P1138 by Vehicle Brand

FAQ

What does the P1138 code mean?

P1138 is an OBD-II diagnostic trouble code that indicates: Lack Of Heated Oxygen Sensor Switches Bank 1 Sensor 2 Switch Indicates Rich

What causes a P1138 error code?

The most common causes of P1138 include: Malfunction of the oxygen sensor bank 1 sensor 2; Open or short circuit in the sensor circuit; Fuel system problems (mixture too rich); Sensor contamination due to oil or coolant leak.

How do I fix a P1138 diagnostic trouble code?

To fix P1138: Check the condition of the oxygen sensor bank 1 sensor 2. Check the continuity of the sensor circuit and connectors. Check the fuel system for leaks. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1138?

Yes, but get it checked soon

How much does it cost to fix P1138?

The estimated repair cost for P1138 is $28–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat