Engine-Codes - Gmc - P0131 GMC

P0131 GMC - HO2S Circuit Low Voltage Bank 1 Sensor 1

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

P0131 GMC Possible Causes

  • Faulty Front Heated Oxygen Sensor (HO2S) Bank 1
  • Front Heated Oxygen Sensor (HO2S) Bank 1 harness is open or shorted
  • Front Heated Oxygen Sensor (HO2S) Bank 1 circuit poor electrical connection
  • Inappropriate fuel pressure
  • Faulty fuel injectors
  • Intake air leaks may be faulty
  • Exhaust gas leaks

How is the P0131 GMC 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.

Tech Notes

Replacing the Front Heated Oxygen Sensor (HO2S) Bank 1 usually takes care of the problem

What is the cost to diagnose the P0131 GMC code

Labor: 1.0

The cost to diagnose the P0131 GMC 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.
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When is the code detected?

The Powertrain Control Module (PCM) monitors the HO2S voltage for being fixed below a predetermined voltage. If the PCM detects the voltage is below a predetermined voltage, the P0131 code is set.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)
  • High Fuel Consumption
  • Excessive Smoke from Exhaust

P0131 GMC Meaning

The Powertrain Control Module (PCM) supplies a voltage of about 450 mV between the Front Heated Oxygen Sensor (HO2S) high and low signal circuits. The oxygen sensor varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean.
The PCM monitors and stores the heated oxygen sensor (HO2S) voltage information. The PCM evaluates the HO2S voltage samples in order to determine the amount of time the HO2S voltage was out of range. The PCM compares the stored HO2S voltage samples taken within each sample period and determines if majority of the samples are out of the operating range.

More Information

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