Engine-Codes - Generic - P1138

P1138 - Lack Of HO2S Bank 1 Sensor 2 Switch Indicates Rich

Repair Importance Level: 3/3
Repair Difficulty Level: 2/3  What is this?
Table of contents

P1138 Possible Causes

  • Exhaust leaks
  • Faulty HO2S Bank 1 Sensor 2
  • HO2S Bank 1 Sensor 2 harness is open or shorted
  • HO2S Bank 1 Sensor 2 circuit poor electrical connection

How is the P1138 code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

What is the cost to diagnose the P1138 code

Labor: 1.0

The cost to diagnose the P1138 code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P1138 Meaning

In order to control emissions, a catalytic converter converts any harmful exhaust emissions into harmless water vapor and carbon dioxide. The Powertrain Control Module (PCM) can monitor this process by using a Rear Heated Oxygen Sensor (HO2S). The Rear HO2S Sensors, located in the exhaust stream past the catalytic converter, produces an output signal which indicates the storage capacity of the catalyst. The Downstream (Rear or Sensor 2) HO2S Sensors are forced rich and lean and monitored by the PCM. The Diagnostic Trouble Code (DTC) will set if the PCM does not detect the output of the Downstream HO2S in a calibrated amount of time.

More Information

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