U0422 on 2017-2024 GMC Yukon: BCM Communication Fault Causes & Fixes

What's Unique About the 2017-2024 Gmc YUKON

On the 2017-2020 GMC Yukon and its platform mates (Tahoe, Suburban, Escalade), this code is frequently linked to a specific, documented issue with the Serial Data Gateway Module (SDGM) and its electrical connectors, as outlined in manufacturer TSBs #PIT5586G and #20-NA-212. The SDGM, which acts as a network router, is located in the left-hand rear of the engine compartment on these models. Rather than an immediate BCM failure, the problem is often in the communication pathway at the SDGM. For 2021 and newer models using GM's more complex Vehicle Intelligence Platform (VIP), network communication is even more critical, and software anomalies requiring a module reprogram are a common cause, per service update N212353390.

Diagnostic Flowchart

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

Generation note: The 2017-2024 range covers two Yukon generations: the 4th gen (2017-2020, K2XX platform) and the 5th gen (2021-2024, T1XX platform). The provided TSBs (#PIT5586G, #20-NA-212) specifically reference the 2017-2020 models, pointing to the SDGM connectors as a primary failure point. The 5th generation features a more advanced electrical architecture (GM VIP) where software-related issues and module programming are more common causes for communication faults. TSB #21-NA-149 also points to engine wiring harness chafing on 2021+ models as a source of various communication codes, including U0422.

Symptoms You May Notice

• Service Stabilitrak message on the Driver Information Center (DIC)
• Service 4WD message on the DIC
• Erratic or non-functional power windows, door locks, or sunroof
• Interior or exterior lights flickering or not working
• Radio or infotainment system glitches or is blank
• Check Engine Light or other warning lamps illuminated
• No-crank or start-then-stall condition
• Instrument panel cluster (IPC) gauges inoperative or fluctuating
• HVAC controls inoperative

Most Likely Causes

1. Poor Connection at Serial Data Gateway Module (SDGM) 🔴 High Probability → Shop Telematics Interface Module This is a well-documented issue for 2017-2020 models, per GM TSBs #PIT5586G and #20-NA-212. The SDGM acts as a router for network data, and poor terminal contact (bent, backed out, loose tension) at its X1 and X2 connectors can corrupt data from the BCM. The SDGM is located in the LH rear of the engine compartment on these models.
   How to confirm: Visually inspect the X1 and X2 connectors at the SDGM for terminals that have backed out, are corroded, or show signs of a loose fit. This requires locating the module, disconnecting the battery, and carefully examining the connections.
   Typical fix: Repairing the affected terminal connections as needed. This may involve re-seating pins, cleaning contacts with electrical cleaner, or replacing the connector pigtail. Applying dielectric grease can prevent future corrosion.
   Est. part cost: $10-$50
2. Wiring Harness Issue (Chafing) 🟡 Medium Probability On trucks and SUVs, large wiring harnesses can be susceptible to chafing against the frame or other components. TSB #21-NA-149 details specific chafe points for 2019+ models, including against the ECM/TCM bracket, upper control arm, and shock tower, which can cause a host of communication codes including U0422.
   How to confirm: Visually inspect harnesses for damage, especially at the locations identified in TSB #21-NA-149. Check for water intrusion at known problem areas like the transfer case connector. A multimeter is needed to check for continuity and shorts to ground on the CAN bus wires.
   Typical fix: Repairing the damaged section of wire and protecting it with anti-abrasion tape or a sleeve. Re-routing or securing the harness with zip ties to prevent future contact.
   Est. part cost: $5-$100
3. Body Control Module (BCM) or SDGM Software Anomaly 🟡 Medium Probability → Shop Body Control Module
   How to confirm: A GM dealer or a shop with a subscription to GM's service information (SPS2) can check for software updates for the BCM and SDGM for your vehicle's specific VIN. TSB #20-NA-212 specifically lists reprogramming the SDGM as a fix for a 'logic lock' condition. Service update N212353390 addresses incorrect SDGM programming on 2021+ models.
   Typical fix: Reprogramming the BCM or SDGM with the latest software using a GM-approved programming tool.
   Est. part cost: $0 (parts), Labor only
4. Failing Body Control Module (BCM) ⚪ Low Probability → Shop Body Control Module
   How to confirm: This is typically diagnosed by exclusion. If all wiring, connectors, grounds, and software have been verified as good, the BCM itself is the likely culprit. A high-end scan tool may be able to detect internal BCM faults. Physical inspection might reveal corrosion from water intrusion.
   Typical fix: Replacing the Body Control Module. This new module will require programming to the vehicle's VIN and specific options, which must be done by a qualified shop.
   Est. part cost: $250-$500

Rare But Worth Checking

• Low Battery Voltage or Failing Alternator: → Shop Vehicle Battery Unstable system voltage can cause communication modules to behave erratically and send corrupt data. Before diving into complex network diagnostics, always ensure the battery is healthy (12.4V+ at rest) and the alternator is charging correctly (typically 13.2-14.5V when running). A weak battery is a common cause of intermittent electronic issues 🎬 See how to fix common GM truck electrical and ground issues. on these vehicles.
• Faulty Wheel Speed Sensor or Hub Bearing: A failing wheel speed sensor can sometimes trigger a 'Service Stabilitrak' message along with a U0422 code. The ABS module, not receiving correct data, can cause communication conflicts on the network. A user on TahoeYukonForum reported U0422 alongside wheel speed sensor codes (C0040), which ultimately pointed to a bad hub bearing.

Diagnosis Steps

1. Verify Battery Health: Ensure the battery is fully charged (12.4V+ at rest) and passes a load test. Check that the charging system is working correctly (typically 13.2-14.5V when running).
2. Scan for All Codes: Use a professional-grade scan tool capable of reading codes from all vehicle modules (BCM, ECM, SDGM, EBCM etc.), not just a basic engine code reader. Note any codes with a '-71' symptom byte, as this indicates 'Invalid Data' and points away from the module that set the code.
3. Consult TSBs: Specifically check for TSBs #PIT5586G, #20-NA-212 (2017-2020 models), and #21-NA-149 (2021+ models). Follow their diagnostic paths first.
4. Inspect SDGM Connectors (2017-2020): Locate the Serial Data Gateway Module in the LH rear of the engine compartment. Disconnect the battery. Disconnect and inspect the X1 and X2 connectors for corrosion, moisture, or pins that have backed out. Repair as needed.
5. Inspect Wiring Harness (All Years): Check for chafing or damage to the CAN bus wiring harnesses, particularly at the points noted in TSB #21-NA-149 for newer models (ECM/TCM bracket, upper control arm, shock tower).
6. Check for Software Updates: A dealer or specialized shop can use GM's Service Programming System (SPS2) to determine if a BCM or SDGM software update is available to address communication glitches.
7. Isolate the Module: If all wiring and connections are good, a technician may need to use advanced diagnostics to isolate the faulty module. This is a process of elimination and is best left to a professional.

Parts You'll Likely Need

• Connector Terminals or Pigtail — To repair the faulty connections at the Serial Data Gateway Module, as recommended by GM TSBs #PIT5586G and #20-NA-212.
  Trusted brands: ACDelco

Related Codes That Often Appear With This One

• U0100 — Lost Communication With ECM/PCM, often set with other U-codes during a network-wide fault.
• U0140 — Lost Communication With Body Control Module, a more direct indicator of the BCM being offline.
• U0155 — Lost Communication With Instrument Panel Cluster (IPC) Control Module, often seen when gauges go dead.
• C0040 — Right Front Wheel Speed Sensor Circuit, can be a root cause triggering Stabilitrak messages and network codes like U0422.
• U0073 — Control Module Communication Bus A Off, indicates a general CAN bus failure often linked to the SDGM or wiring issues.

Technical Service Bulletins (TSBs) & Recalls

• PIT5586G: Instructs dealers to check for logic lock of Serial Data Gateway Module or for terminal concerns in its connectors.
• PIT5586B: Instructs dealers to check Serial Data Gateway Module X2 connector for terminal concerns and repair as needed.
• 22-NA-187: Links U0422-71 to potential water intrusion at the Transfer Case Actuator connector on 2020 models.

Platform-Specific Known Issues

• TSB #PIT5586G / #20-NA-212 (for 2017-2020 models) explicitly lists U0422 with a host of other communication codes caused by a 'logic lock' of the SDGM or, more commonly, terminal issues in its X1 and X2 connectors.
• TSB #21-NA-149 (for 2021+ models) identifies specific engine wiring harness chafe points near the ECM/TCM bracket and upper control arm that can cause U0422 among many other codes.
• Service Update N212353390 notes that 2021+ models that had their SDGM replaced in service may not have been programmed correctly, causing communication issues that require a reprogram.

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 in one of the modules. A reading near 0 Ohms indicates a short between the CAN High and CAN Low wires.
• CAN High Voltage — expected: Approximately 2.5V (recessive state) to 3.5V (dominant state). Failure: Significant deviation from this range, or voltage that is stuck high or low, indicates a bus fault.
• CAN Low Voltage — expected: Approximately 2.5V (recessive state) to 1.5V (dominant state). Failure: Significant deviation from this range, or voltage that is stuck high or low, indicates a bus fault.
• BCM Power Pin Voltage — expected: 12.0 ± 0.5 V. Failure: Low or unstable voltage indicates a power supply or ground issue to the module itself.

Hidden / Shadow Codes Worth Checking

• U0422-71: The '-71' is a GM-specific 'symptom byte' meaning 'Invalid Serial Data Received'. This is a critical diagnostic clue. It means the module setting this code (e.g., the ECM) is receiving bad data from the BCM, but the BCM itself may not be the root cause. The fault could be an input to the BCM (like a sensor) or a network wiring issue causing data corruption. (see via A professional scan tool like the GM GDS2 will display the full DTC with its two-digit symptom byte. Basic code readers may only show the generic U0422.)

Scan Tool Commands That Help

• GM GDS2: Vehicle DTC Information — This is the first step to scan all modules on the vehicle's networks. It will display a complete list of current and history codes from every module, including the critical symptom bytes needed for accurate diagnosis.
• GM GDS2: Module Diagnostics > BCM > Control Functions — This allows a technician to perform bidirectional tests by directly commanding the BCM to activate outputs like headlights, door locks, or windows. If the command works (e.g., the headlights turn on), it proves the BCM, its output wiring, and the headlight itself are functional, pointing the diagnosis toward an input or network communication problem.

Wiring & Ground Locations

• G218 — Inside the cabin, on the driver's side, behind the A-pillar trim / kick panel, near the speaker.. This is a major interior ground point. On K2XX platform trucks (2017-2020), sound-deadening foam insulation is often improperly installed from the factory and gets pinched under the ground nut, causing a poor connection. This leads to a host of bizarre electrical issues, including network communication faults.
• SDGM Connectors X1 & X2 — On 2017-2020 models, the Serial Data Gateway Module is located in the left-hand rear of the engine compartment.. TSBs #PIT5586G and #20-NA-212 specifically call out these connectors as a primary failure point for a long list of U-codes, including U0422. The terminals can become bent, loose, or corroded, disrupting network traffic.
• Engine-to-Chassis Ground Strap — Typically on the passenger side of the engine bay, running from the rear of the cylinder head to a stud on the firewall.. This main ground strap ensures the engine block has a solid ground reference to the vehicle body. If it breaks or corrodes, modules can lose their ground reference, leading to voltage fluctuations and data corruption on the CAN bus.
• Frame Grounds Behind Front Wheels — On the frame rails directly behind both front wheels.. These grounds are in a terrible location and are constantly exposed to water, salt, and road debris, making them highly susceptible to corrosion. A poor connection here can cause widespread electrical and communication problems.

Real Owner Repair Stories

• YouTube user 'Dustin T' (2014-2018 Chevrolet Silverado (K2XX Platform)) — Sporadic electrical issues, flickering dash lights, radio shutting off, vehicle stalling at idle.
  ❌ Tried (didn't work) Initial checks did not immediately point to a single cause.
  ✅ What actually fixed it The G218 ground on the driver's side interior was faulty. Sound deadening material was trapped under the ground nut from the factory, preventing a solid connection. Removing the nut, cleaning the contact surfaces, trimming the foam away, and re-tightening the nut permanently solved the electrical problems.
• YouTube user 'GM Truck Life' (Chevrolet Silverado (K2XX Platform)) — ABS light, check engine light, battery light, slow power windows, low voltage reading.
  ❌ Tried (didn't work) Unknown
  ✅ What actually fixed it The main engine-to-chassis ground strap, located on the passenger side from the back of the engine block to the firewall, was broken. Replacing this ground strap restored proper voltage and fixed all the electrical issues.

OEM Part Supersession History

• 13509768, 13524297, 13524298, 13599317 → 13599318 — Part revision and consolidation by the manufacturer.
  Heads up: This part requires programming with GM's Service Programming System (SPS) after installation to function correctly with the vehicle's specific options.
• N/A → 13542838 — New part for the updated T1XX platform architecture.
  Heads up: This part is for the newer GM Vehicle Intelligence Platform (VIP) and is not backwards compatible with the older K2XX platform vehicles.

Model Year Variations Within This Range

• 2017-2020 (K2XX Platform): These models are highly prone to the SDGM connector issue (TSB PIT5586G) and the G218 interior ground fault. The SDGM is located in the engine bay.
• 2021-2024 (T1XX Platform): These models use the newer Vehicle Intelligence Platform (VIP) architecture. The SDGM location and part number are different. While wiring/ground issues can still occur, software anomalies and programming-related fixes are more common. These models have multiple fuse/relay centers (engine bay, instrument panel, rear compartment), indicating a more distributed electrical system.