AutoCodes – GMC – B320C GMC

B320C GMC Code - Middle Door Window Motor

Quick Answer

The front door, rear door and middle door power window motors communicate with the Drivers Door Module (DDM), Passenger Door Module (PDM) and Rear Door Modules and Middle Door Modules over the LIN BUS. Common causes include Faulty Middle Door Window Motor, Middle Door Window Motor harness is open or shorted, Middle Door Window Motor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B320C GMC indicates Middle Door Window Motor.
Common causes: Common causes include Faulty Middle Door Window Motor, Middle Door Window Motor harness is open or shorted, Middle Door Window Motor circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 419

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 05, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B320C GMC Description

The front door, rear door and middle door power window motors communicate with the Drivers Door Module (DDM), Passenger Door Module (PDM) and Rear Door Modules and Middle Door Modules over the LIN BUS. The motors contain a logic module which must be normalized or programmed any time the window motor is serviced to provide proper operation and communication between door modules and window motors. The Diagnostic Trouble Code (DTC) sets when an internal malfunction has been detected by the DDM or PDM in the Front Door, Rear Door, or Middle Door window motor while commanding the window motor UP/DOWN.

OBDII Code B320C GMC - Middle Door Window Motor - AutoCodes.com — B320C GMC Code - Middle Door Window Motor

What does this mean?

What are the Possible Causes of the DTC B320C GMC?

Faulty Middle Door Window Motor
Middle Door Window Motor harness is open or shorted
Middle Door Window Motor circuit poor electrical connection
Faulty Middle Door Module

How to Fix the DTC B320C GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

B320C 39 Middle Door Window Motor Internal Electronic Failure/Discard
B320C 42 Middle Door Window Motor Calibration Data Set Not Programmed
B320C 4B Middle Door Window Motor Calibration Not Learned

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B320C GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B320C GMC Code

1. What does the OBDII code B320C mean on a GMC vehicle?

The B320C code indicates a fault related to the middle door window motor, typically involving a malfunction in its operation or communication with the control module.

2. What are the common symptoms of the B320C code?

Symptoms may include the middle door window not operating, intermittent window movement, or unresponsiveness when using the window switch.

3. What causes the B320C code to appear?

Common causes include a faulty window motor, damaged wiring or connections, a malfunctioning window switch, or an issue with the door control module.

4. Can a blown fuse cause the B320C code?

Yes, a blown fuse in the circuit powering the middle door window motor can trigger the B320C code.

5. How do I diagnose the B320C code?

Start by checking the window motor, wiring, and connectors for damage or corrosion. Test the window switch and inspect the fuse. Use a scan tool to confirm the code and any related faults.

6. Is the middle door window motor likely to need replacement if the B320C code is present?

If the motor is unresponsive or fails testing, itâ€™s possible the motor will need replacement. However, always check wiring and other components first.

7. How much does it cost to fix the B320C code on a GMC?

Repair costs vary but replacing a middle door window motor typically costs $150â€“$300, including parts and labor, depending on the vehicle model and location.

8. Can I drive with the B320C code active?

Yes, the B320C code usually does not affect drivability, but the middle door window may remain inoperative until repaired.

9. Will clearing the B320C code without repairs fix the problem?

Clearing the code may temporarily reset the system, but if the root cause isnâ€™t addressed, the code will likely return.

10. Can a software update resolve the B320C code?

In rare cases, a software update for the door control module might fix the issue if itâ€™s related to communication errors. Check with your GMC dealer for updates.