AutoCodes – Buick – C0550 Buick

C0550 Buick Code - Electronic Control Unit

Quick Answer

This is an internal fault detection of the Transfer Case Shift Control Module (TCCM). Common causes include Faulty Transfer Case Shift Control Module (TCCM), Transfer Case Shift Control Module (TCCM) harness is open or shorted, Transfer Case Shift Control Module (TCCM) 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: C0550 Buick indicates Electronic Control Unit.
Common causes: Common causes include Faulty Transfer Case Shift Control Module (TCCM), Transfer Case Shift Control Module (TCCM) harness is open or shorted, Transfer Case Shift Control Module (TCCM) 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 8,049

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 Jun 27, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code C0550 Buick Description

This is an internal fault detection of the Transfer Case Shift Control Module (TCCM). This fault is handled inside the TCCM. No external circuits are involved.
At each power-up, the TCCM runs a self-test on the following:
- EEPROM Checksum
- ROM Checksum
- RAM Checksum
- RAM Malfunction

OBDII Code C0550 Buick - Electronic Control Unit - AutoCodes.com — C0550 Buick Code - Electronic Control Unit

What does this mean?

What are the Possible Causes of the DTC C0550 Buick?

Faulty Transfer Case Shift Control Module (TCCM)
Transfer Case Shift Control Module (TCCM) harness is open or shorted
Transfer Case Shift Control Module (TCCM) circuit poor electrical connection

How to Fix the DTC C0550 Buick?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C0550 Buick 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.