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U0073 on Buick: Symptoms, Causes & Fix

Control Module Communication Bus A Off

Official technical diagnostic wire for fault code U0073 specifically affecting Buick vehicles (Enclave, Encore GX, Envision, Envista).

Sensor Voltage Ref
0.1V – 5.0V Ref
Buick Factory Standard
CAN Bus Speed
500 kbps CAN-FD
ISO 15765-4 Diagnostic Bus
Drivability Status
Not Recommended
Critical urgency level
Est. Repair Cost
$150 - $850 (DIY: $40 - $200)
Parts & Labor DIY
Model-Specific Diagnostic Wires

Select Your Buick Model for U0073:

4 Models Available

1. Common Symptoms on Buick Vehicles

When Buick Engine Control Modules (ECM) trigger fault code U0073, drivers typically report:

StabiliTrak / Traction / ABS / Engine warning lights lit on Buick Powertrains
Transmission shifting harshly or refusing to shift out of 2nd gear on Buick Powertrains
No communication with TCM, ABS, or BCM on Buick Powertrains
Engine may refuse to crank on Buick Powertrains

2. Root Causes on Buick Engines

Historical diagnostic claims across Buick engines point to the following failure distribution:

55%
Loose or corroded ground connection on transmission or frame (Buick OEM Part)
25%
Faulty Transmission Control Module (TCM) or ABS module pulling bus down (Buick OEM Part)
12%
Poor connection at large body-to-chassis pass-through harness connector (Buick OEM Part)
8%
Aftermarket accessory (remote starter, GPS tracker, cheap OBD scanner) broadcasting invalid data (Buick OEM Part)

3. Step-by-Step Fix Protocol for Buick

01
Unplug All Aftermarket OBD-II Devices

Remove any aftermarket insurance dongles, GPS trackers, or scan tools plugged into the DLC port. on Buick engines.

Required Tool: None
02
Inspect Frame and Transmission Ground Straps

Inspect braided ground straps on engine and transmission. Clean all contact surfaces to bare metal. on Buick engines.

Required Tool: Wire Brush, Sockets
03
Perform Full Vehicle Network Topology Scan

Scan all modules on vehicle. Note which modules are online and which are offline to pinpoint the break in the network daisy-chain. on Buick engines.

Required Tool: Full-System OBD-II Diagnostic Scanner
04
Check Terminating Resistance (60 Ohms)

Verify 60 ohms across Pins 6 and 14 with battery disconnected. on Buick engines.

Required Tool: Multimeter
05
Clear All System DTCs & Road Test

Clear DTCs from all modules and road test to verify error-free network transmission. on Buick engines.

Required Tool: Scan Tool
Recommended Parts & Testing Tools

Equipment for Diagnosing Buick (U0073)

Prime Fast Delivery & Verified Fitment
Direct-Fit Replacement Part

Buick OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

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

$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
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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 BuickVerified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
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4. Buick U0073 Frequently Asked Questions

What does code U0073 mean on a Buick?

On Buick vehicles, U0073 indicates that the Engine Control Module (ECM) detected control module communication bus a off. This typically points to Loose or corroded ground connection on transmission or frame or Faulty Transmission Control Module (TCM) or ABS module pulling bus down.

Can I continue driving my Buick with code U0073?

No. Bus is shut down due to excessive transmission errors, leaving vehicle in unpredictable limp mode. Because this code carries a Critical severity rating on Buick powertrains, we recommend scanning live data values promptly to prevent secondary damage.

How much does it cost to fix code U0073 on a Buick?

Estimated DIY parts cost ranges from $150 - $850 (DIY: $40 - $200), while professional shop repairs at an authorized Buick dealership or independent specialist typically range from $180 to $380 including diagnostic labor.