U1026 2016 GMC Sierra Code - Lost Communication with Transfer Case Control Module
Quick Answer
Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Transfer Case Control Module, Transfer Case Control Module harness is open or shorted, Transfer Case Control Module 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
- U1026 2016 GMC Sierra indicates Lost Communication with Transfer Case Control Module.
- Common causes
- Common causes include Faulty Transfer Case Control Module, Transfer Case Control Module harness is open or shorted, Transfer Case Control Module 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.
Code U1026 2016 GMC Sierra Description
What are the Possible Causes of the DTC U1026 2016 GMC Sierra?
- Faulty Transfer Case Control Module
- Transfer Case Control Module harness is open or shorted
- Transfer Case Control Module circuit poor electrical connection
How to Fix the DTC U1026 2016 GMC Sierra?
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.
Code Tech Notes
It can occur if:
Someone changes a battery while the ignition switch is left on, that is, left in the Run position.
Someone flashes/upgrades their engine controller - other modules unable to communicate with PCM during this process - this will set U1026 at a multitude of controllers on the vehicle - all false codes. Erase and carry on.
May need to disconnect both battery cables and touch them together for 15 seconds. Reattach battery cables, positive first, then negative and see if a soft reset helps.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the U1026 2016 GMC Sierra 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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Frequently Asked Questions about U1026 2016 GMC Sierra Code
1. What does the OBDII code U1026 mean on a 2016 GMC Sierra?
The U1026 code indicates a loss of communication with the Transfer Case Control Module (TCCM), which manages the vehicle's four-wheel-drive system.
2. What are the common symptoms of the U1026 code?
Symptoms may include the Service 4WD light illuminating, inability to shift into or out of 4WD modes, and erratic or unresponsive transfer case operation.
3. What causes the U1026 code to appear?
Common causes include wiring or connector issues, a faulty Transfer Case Control Module, communication bus errors, or a failing Body Control Module (BCM).
4. Can a bad Transfer Case Control Module trigger the U1026 code?
Yes, a malfunctioning TCCM is a potential cause of the U1026 code due to its inability to communicate with other modules.
5. How do you diagnose the U1026 code?
Diagnosis involves checking for damaged wiring, loose or corroded TCCM connectors, verifying communication on the CAN bus with a scan tool, and testing the TCCM for proper operation.
6. Can I drive my 2016 GMC Sierra with the U1026 code active?
Driving is possible, but you may lose four-wheel-drive functionality, which could impact performance in certain conditions like off-roading or slippery roads.
7. How do you fix the U1026 code on a GMC Sierra?
Repairs may involve fixing or replacing damaged wires, cleaning or reconnecting TCCM connectors, reprogramming or replacing the TCCM, or addressing CAN bus issues.
8. Does the U1026 code always mean the TCCM is bad?
No, the TCCM may not be at fault. The issue could also stem from wiring, connectors, or other modules on the communication network.
9. Can a dead battery cause the U1026 code to appear?
Yes, a weak or dead battery can disrupt module communication, potentially triggering the U1026 code.
10. Is reprogramming the TCCM necessary to fix the U1026 code?
Reprogramming may be required if the TCCM has software issues or needs to be replaced, but this depends on the specific diagnosis.
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