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U0102 on Buick Envista

Lost Communication with Transfer Case Control Module (TCCM)

Factory diagnostic protocol and troubleshooting wire for fault code U0102 specifically for the Buick Envista (2024–2026, 1.2L ECOTEC Turbo 3-Cyl (137HP / 162 lb-ft)).

Verified OEM Telemetry & Field Repair Tree
Buick Envista2024–2026
Buick Envista
SUV1.2L ECOTEC Turbo 3-Cyl (137HP / 162 lb-ft)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
Envista SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Drivable (Short Trip)
Medium urgency level
Est. Repair Cost
$150 - $650 (DIY: $50 - $220)
Parts & Labor DIY
Check U0102 On Another Buick Model:
Diagnose U0102 on Specific Envista Model Year:

1. Symptoms of U0102 on Buick Envista

When the Engine Control Module (ECM/PCM) on your Buick Envista (1.2L ECOTEC Turbo 3-Cyl (137HP / 162 lb-ft)) logs fault code U0102, drivers commonly observe:

'Service 4WD' or '4WD System Error' message on dash on Buick Envista (1.2L ECOTEC Turbo 3-Cyl (137HP / 162 lb-ft))
4WD selector switch unresponsive (lights out on switch) on Buick Envista (1.2L ECOTEC Turbo 3-Cyl (137HP / 162 lb-ft))
Vehicle stuck in 2WD or last selected 4WD mode on Buick Envista (1.2L ECOTEC Turbo 3-Cyl (137HP / 162 lb-ft))
Buick Envista OBD-II Port Location
The 16-pin diagnostic connector is located Under driver steering column. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Buick Envista

Historical warranty claims and technical repair bulletins for Buick Envista point to the following failure distribution:

55%
Corroded TCCM power/ground wiring under vehicle (Buick OEM Part)
25%
Blown 4WD / TCCM fuse in engine fuse panel (Buick OEM Part)
12%
Faulty Transfer Case Control Module (Buick OEM Part)
8%
Faulty transfer case shift encoder motor (Buick OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Buick Envista.

3. Step-by-Step DIY Repair Guide for Buick Envista

01
Check 4WD / TCCM Fuses

Inspect ATC / 4WD fuses with test light. on the Buick Envista equipped with 1.2L ECOTEC Turbo 3-Cyl (137HP / 162 lb-ft).

Required Tool: Test Light
02
Inspect TCCM Connector

Check module under driver dash or seat for water intrusion. on the Buick Envista equipped with 1.2L ECOTEC Turbo 3-Cyl (137HP / 162 lb-ft).

Required Tool: Flashlight
03
Test CAN Bus Wires at TCCM

Verify 2.5V CAN signals reach the module. on the Buick Envista equipped with 1.2L ECOTEC Turbo 3-Cyl (137HP / 162 lb-ft).

Required Tool: Multimeter
04
Replace TCCM & Clear Codes

Install replacement module and clear trouble codes. on the Buick Envista equipped with 1.2L ECOTEC Turbo 3-Cyl (137HP / 162 lb-ft).

Required Tool: Socket Set, Scan Tool
Recommended Parts & Testing Tools

Equipment for Diagnosing Buick Envista (U0102)

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Direct-Fit Replacement Part

Buick Envista OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

Direct-fit replacement assembly engineered to OEM tolerances for Buick Envista.

$45 – $95 Prime
Check Fitment on Amazon
Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

4.6 / 5.0 (Best Seller)

Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.

$29.99 Prime
View on Amazon
Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

4.7 / 5.0 (50,000+ Reviews)

Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

Compare OEM & Aftermarket Replacement Sensors for Buick EnvistaVerified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
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Other Common Fault Codes on Buick Envista

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Buick Envista:

4. Buick Envista U0102 FAQs

What causes code U0102 to trigger on a Buick Envista?

On the Buick Envista (1.2L ECOTEC Turbo 3-Cyl (137HP / 162 lb-ft)), U0102 is most frequently caused by Corroded TCCM power/ground wiring under vehicle or Blown 4WD / TCCM fuse in engine fuse panel.

Where is the OBD-II port located on my Buick Envista?

On the Buick Envista, the 16-pin DLC diagnostic connector is located Under driver steering column. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Buick Envista with code U0102?

Yes, in 2WD. 4WD and Auto 4x4 functions will be inoperative. Given that U0102 carries a Medium severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.