U0140 on 2015-2022 GMC Yukon XL: Lost Communication With Body Control Module Causes and Fixes

What's Unique About the 2015-2022 Gmc YUKON XL

For this generation of GMC Yukon XL and its sister platforms (Chevy Tahoe/Suburban, Cadillac Escalade), electrical issues stemming from poor ground connections are a well-documented problem. Manufacturer TSBs, specifically PIT5405C, point technicians to check the BCM ground G218 when a U0140 code is present. The TSB notes that the dash insulator mat can get trapped under the ground's eyelet connector, causing high resistance. This makes the grounding point a known weak link 🎬 Watch: How this common grounding issue causes electrical failures. and a much higher probability cause than on other vehicles where a faulty module might be more common. Additionally, TSBs also point to issues with the Serial Data Gateway Module (SDGM) connectors or logic lock-ups as a frequent source 🎬 See how to install an SDGM bypass harness. of communication failures on this platform.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Generation note: The 2015-2022 year range covers two generations of the GMC Yukon XL: the end of the fourth generation (2015-2020, K2UG platform) and the beginning of the fifth generation (2021-2022, T1UG platform). While the underlying cause related to BCM communication and grounding is common, the exact location of components and wiring can differ. The K2XX platform specifically utilizes a separate Serial Data Gateway Module (SDGM) that is a known point of failure. The grounding issue at G218 is well-documented for the K2XX models. Both generations share a similar electrical architecture, making them vulnerable to these communication faults, though the 2021+ models use the newer 'Global B' architecture which has its own unique failure points.

Symptoms You May Notice

• Radio and/or climate controls go blank or are inoperative.
• Multiple, seemingly unrelated warning lights on the instrument cluster.
• "Service Stabilitrak" message on the driver information center.
• "Service Trailer Brake System" message appears, even when not towing.
• Power windows, door locks, or remote keyless entry not working.
• Interior or exterior lights behaving erratically or not turning on.
• Wipers not functioning correctly or turning on by themselves.
• Instrument panel gauges drop to zero or fluctuate wildly.
• Vehicle may not start or crank.

Most Likely Causes

1. Poor or Corroded Body Control Module (BCM) Ground 🔴 High Probability → Shop Body Control Module GM TSB #PIT5405C directly identifies the BCM ground G218 as a primary cause for U0140. It specifies that the dash insulator mat can get trapped under the ground terminal, creating a poor connection.
   How to confirm: Locate ground point G218, which is in the driver's side footwell on the body A-pillar, often behind the kick panel or carpet. Inspect for looseness, corrosion, or trapped material under the eyelet. A voltage drop test on the ground circuit can confirm high resistance.
   Typical fix: Disconnect the battery. Remove the ground nut/bolt, remove the eyelet connector, and clean the terminal and the chassis surface to bare metal. Ensure no insulation is caught underneath and securely re-tighten the connection. This is a very common and effective repair.
   Est. part cost: $0-$5
2. Serial Data Gateway Module (SDGM) Fault 🟡 Medium Probability → Shop Telematics Interface Module The SDGM acts as a traffic controller for network data. TSB #PIT5586G points to issues like 'logic lock' or poor terminal connections at the SDGM's X1 and X2 connectors as a cause for widespread communication codes, including U0140.
   How to confirm: The SDGM is located behind the driver's side lower dash panel, near the OBD-II port. A technician can check for power, ground, and proper pin fitment at the connectors. A high-end scan tool may also show the SDGM is not communicating.
   Typical fix: Disconnecting the battery for 30 minutes can sometimes reset a 'logic lock' state. More commonly, the fix involves disconnecting the SDGM connectors, inspecting for bent or loose pins, applying dielectric grease, and re-seating them securely. In some cases, the SDGM itself fails and requires replacement and programming.
   Est. part cost: $50-$200
3. Faulty Body Control Module (BCM) 🟡 Medium Probability → Shop Body Control Module Internal failure of the BCM can occur, but it is often misdiagnosed. TSB #PIT4730B warns technicians not to replace the BCM for intermittent U0140 codes without first thoroughly checking for wiring issues, as a temporary short on the CAN bus can make the BCM appear offline until the ignition is cycled.
   How to confirm: After confirming the BCM has proper power and ground (at the module connector) and the CAN bus network wiring is intact, a professional scan tool will still be unable to communicate with the BCM. This points to an internal module failure.
   Typical fix: Replace the Body Control Module. The new module must be programmed to the vehicle's specific VIN and options using dealer-level software or a pre-programmed service. 🎬 Watch this walkthrough on how to replace a BCM.
   Est. part cost: $250-$500
4. Damaged Wiring or Loose Connections ⚪ Low Probability Wiring harnesses, particularly in the driver's kick panel, A-pillar, or where they pass over the frame under the hood, can be disturbed or chafed. Aftermarket accessory installation (e.g., remote start, alarms) is a common source of wiring damage or interference.
   How to confirm: Visually inspect the wiring harnesses connected to the BCM and SDGM for any signs of damage, chafing, or corrosion. Check for pin tension at the BCM connectors. One owner on a forum found the harness had rubbed through on the frame below the underhood fuse box.
   Typical fix: Repair the damaged section of the wiring harness with sealed butt connectors and protect it from future chafing. Re-seat any loose connectors.
   Est. part cost: $10-$100
5. Low Battery Voltage or Failing Alternator ⚪ Low Probability → Shop Vehicle Battery Control modules can stop communicating when system voltage drops below a certain threshold (typically around 9-10 volts). While not specific to this platform, it's a universal cause for communication codes.
   How to confirm: Test the battery's state of charge and health (must be >12.4V at rest). With the engine running, check the alternator output to ensure it's within the correct range (typically 13.5-14.5 volts). TSB PIT5405A recommends a loaded voltage drop test on the battery cables, which should not exceed 200mV.
   Typical fix: Recharge or replace the battery and/or replace the alternator.
   Est. part cost: $150-$600

Rare But Worth Checking

• Faulty Terminating Resistor:
• Aftermarket Electronics Interference:

Diagnosis Steps

1. Check Battery Health: Ensure the battery is fully charged (>12.4V) and the terminals are clean and tight. A weak battery can cause random communication codes.
2. Scan for All Codes: Use a professional scan tool to read codes from ALL modules, not just the engine computer. Note which modules are reporting U0140 and which, if any, are not communicating at all.
3. Disconnect Aftermarket Devices: Unplug any aftermarket OBD-II devices, remote starters, or alarms to eliminate them as a source of interference.
4. Inspect BCM Fuses: Check all fuses related to the Body Control Module in the interior and under-hood fuse panels.

Parts You'll Likely Need

• Body Control Module (BCM) (OEM #Varies by year and options (e.g., 23107324 for some models)) — If the module has failed internally after confirming good power, ground, and wiring, it must be replaced. This is a likely cause after a bad ground or SDGM connection has been ruled out.
  Trusted brands: ACDelco (GM Genuine), Dorman
  OEM price range: $350-$500
  Aftermarket price range: $250-$400

Related Codes That Often Appear With This One

• U0073 — This code indicates a general 'Control Module Communication Bus 'A' Off' fault, often appearing with more specific communication codes like U0140. TSB PIT5405C links U0073 and U0140 directly to intermittent wiring shorts and grounding issues.
• U0100 — Lost Communication with ECM/PCM. This can occur if the BCM acts as a gateway module and its failure disrupts the entire network.
• U0101 — Lost Communication with TCM. Similar to U0100, the BCM's failure can interrupt communication with the transmission controller.
• U0121 — Lost Communication With Anti-Lock Brake System (ABS) Control Module. This is another module on the network that can log a code if the BCM goes offline.

Technical Service Bulletins (TSBs) & Recalls

• PIT5405C: Mentions U0140 as one of many codes that can be set due to a poor BCM ground (G218), specifically calling out trapped dash insulation as the cause.
• PIT5405A: An earlier version connecting U0140 with blank displays and other codes, pointing to a check of the BCM ground.
• PIT5586G: Instructs technicians to check the Serial Data Gateway Module (SDGM) for connector terminal issues or a 'logic lock' state when multiple U-codes are present.
• PIT4730B: Describes how an intermittent wiring short can make the BCM appear offline, advising against immediate BCM replacement without thorough wiring diagnosis.

Platform-Specific Known Issues

• GM Technical Service Bulletin #PIT5405C directly links a long list of communication and electrical DTCs, including U0140, to a potential issue with the body control module ground (G218), noting that dash insulation can get trapped under the connector.
• GM Technical Service Bulletin #PIT5586G points to the Serial Data Gateway Module (SDGM) connectors or a 'logic lock' state as a cause for U0140 and other communication failures.
• GM Technical Service Bulletin #PIT4730B warns that an intermittent short to ground on the CAN bus wiring can cause the BCM to appear offline for an entire ignition cycle, leading to misdiagnosis of a bad BCM. The issue often occurs over rough roads.

Mechanic-Grade Diagnostic Values

• CAN Bus Network Resistance — expected: Approximately 60 Ohms. Failure: A reading of 120 Ohms indicates an open circuit or a missing terminating resistor. A reading near 0 Ohms indicates a short between the CAN High and CAN Low wires.
• Battery Cable Voltage Drop — expected: Less than 200 mV (0.2 V). Failure: A reading above 200 mV indicates high resistance in the positive or negative battery cables, which can cause module communication issues.
• CAN Bus Wires to Ground Resistance — expected: OL (Over Limit) or Mega-Ohms (MΩ). Failure: Any low resistance reading indicates a short to ground on either the CAN-H or CAN-L wire, which will disrupt network communication.
• BCM Power Supply Voltage — expected: 12.2 - 12.8 V. Failure: Voltage below the minimum threshold (typically ~9V) can cause the BCM to shut down and stop communicating.

Scan Tool Commands That Help

• GDS2 (GM Dealer Tool): Module Status / Network Topology — This is a primary diagnostic step to get a visual overview of the entire vehicle network. It quickly confirms which modules are online and which, like the BCM, are not communicating.
• GDS2 (or equivalent professional scanner): BCM Programming & Setup — This function is required after replacing the Body Control Module. The new module must be programmed with the vehicle's VIN and specific configuration data to function correctly.
• GDS2 (or equivalent professional scanner): Theft Deterrent Relearn — After BCM replacement or if the security system is causing a no-start, this procedure synchronizes the BCM with the vehicle's anti-theft components. A manual 30-minute relearn procedure also exists.

Wiring & Ground Locations

• G218 — On the driver's side A-pillar, behind the lower dash kick panel or carpet, near the hood release lever.. This is the primary ground for the Body Control Module. GM TSB #PIT5405C explicitly states that the dash insulator mat can get trapped under this ground's eyelet, causing high resistance and leading directly to code U0140 and numerous other electrical faults.
• BCM Location (2015-2020) — Behind the driver's side lower dashboard, to the left of the steering column and often just above the OBD-II port and parking brake assembly.. Technicians need to access the BCM to test its power and ground circuits directly at the connectors and to inspect the wiring harness for damage.
• SDGM Location (2015-2020) — Behind the driver's side lower dash panel, often in close proximity to the BCM and OBD-II port.. The Serial Data Gateway Module is a known failure point for communication issues. Access is required to inspect its connectors (X1, X2) for pin fitment issues or to perform a reset by disconnecting it.
• BCM Connector X7, Pin 27 (2021-2022) — At the Body Control Module on T1 platform vehicles.. A 2024 TSB identifies this specific pin, for the theft-deterrent glass breakage sensor, as a potential source of high resistance (>20 ohms) that can cause BCM-related issues like battery drain.

Real Owner Repair Stories

• tahoeyukonforum.com user (2015 GMC Yukon) — Radio screen going blank, no blinker sounds, multiple warning messages on the dash, and instrument panel gauges dropping to zero.
  ❌ Tried (didn't work) Replacing the battery, Checking all related fuses
  ✅ What actually fixed it The owner found GM TSB PIT5405, which described the exact symptoms. They located ground G218 in the driver's footwell, discovered the dash insulation mat was caught under the ground connector, removed the interference, cleaned the contact surfaces, and securely re-tightened the ground nut. This single repair completely resolved all electrical issues.

OEM Part Supersession History

• 13536380, 13541808, 13546978 → 13548775 — Standard part revision and consolidation by the manufacturer.
  Heads up: This part number is for the T1 platform (2021+) and is not compatible with the K2 platform (2015-2020).
• Varies by VIN → Varies by VIN — N/A
  Heads up: The 2015-2020 K2 platform uses a 'Global A' architecture BCM (often Bosch/Continental). The 2021+ T1 platform uses a 'Global B' architecture BCM (often Denso). These are not interchangeable. Always order based on VIN.

Model Year Variations Within This Range

• 2015-2020 (K2 Platform): These models use the 'Global A' electrical architecture. The most prevalent documented causes for U0140 are the G218 ground insulation issue and faults with the separate Serial Data Gateway Module (SDGM). The BCM is typically made by Bosch or Continental.
• 2021-2022 (T1 Platform): These models use the newer 'Global B' / Vehicle Intelligence Platform (VIP) architecture. The BCM is a different design (e.g., Denso) and the SDGM function is integrated differently. A documented issue specific to this platform is high resistance in the theft-deterrent glass breakage sensor circuit causing BCM faults.