Engine-Codes - GMC - B138A GMC

B138A GMC Code - Control Module Voltage Reference Output Circuit

- Code Popularity: 595 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents
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What are the Possible Causes of the DTC B138A GMC?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Rear Parking Assist Alarm Sensor
  • Rear Parking Assist Alarm Sensor harness is open or shorted
  • Rear Parking Assist Alarm Sensor circuit poor electrical connection
  • Faulty Parking Assist Control Module

Code Tech Notes

DTC B138A 03: Control Module Voltage Reference Output Circuit Low Voltage
DTC B138A 07: Control Module Voltage Reference Output Circuit High Voltage

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How to Fix the DTC B138A GMC?

Check 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 pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the B138A GMC code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

What are Code Possible Symptoms?

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

What Does the B138A GMC Code Mean?

The object sensors are 3-wire sensors that are used to determine the distance between the vehicle and an object of interest. The Parking Assist Control Module supplies 8 V to the object sensors via the 8 V reference circuit and provides ground via the low reference circuit. The Parking Assist Control Module triggers the sensors in a sequential loop. After each sensor transmits, the Parking Assist Control Module uses the sensor echo received through the signal circuit to calculate the distance and position of an object.

B138A GMC Code - Control Module Voltage Reference Output Circuit

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