U0075 on 2017-2018 GMC Acadia: Active Safety System Communication Fault Causes & Fixes

What's Unique About the 2017-2018 Gmc ACADIA

The 2017 model year marked the beginning of the second-generation Acadia, which introduced a much more complex suite of Advanced Driver-Assistance Systems (ADAS) on the C1XX platform. Code U0075 is directly tied to the communication network for these new features. GM even issued a technical service bulletin (PIT5441C) specifically for this code on the Acadia and other similar platforms, highlighting that the issue is often related to the Active Safety Module or its dedicated communication bus, which uses terminals 3 and 11 of the DLC.

Diagnostic Flowchart

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

Symptoms You May Notice

• "Service Active Safety System" message on the instrument cluster
• "Service Front Camera" message
• Blind-spot monitoring system is inoperative
• Adaptive Cruise Control is unavailable
• Forward Collision Alert system is disabled
• Park assist features do not work
• Lane Keep Assist (LKA) indicator may not appear in the DIC.
• Parasitic battery drain leading to a dead battery.

Most Likely Causes

1. Wiring Harness or Connector Issue 🔴 High Probability Network wiring can be susceptible to damage from moisture, corrosion, or physical stress. TSB PIT5700B points to a specific open circuit in the harness near splice JX300, which on the Acadia is located on the floor near the driver's seat. This splice is a known failure point that can cause loss of communication with the ASCM.
   How to confirm: A technician will perform a visual inspection of the wiring harness leading to the Active Safety Control Module (ASCM) and related sensors. They will also use a multimeter to check for continuity, shorts to ground, or shorts to power on the communication bus circuits (terminals 3 and 11 at the DLC). Diagnosis may involve isolating sections of the network by disconnecting splice packs to pinpoint the location of the fault.
   Typical fix: Repairing the damaged section of the wire (such as at splice JX300) or replacing the affected connector pigtail.
   Est. part cost: $20-$100
2. Faulty Active Safety Control Module (ASCM) 🟡 Medium Probability The ASCM (K124) is the central computer for the ADAS features. Like any electronic module, it can fail internally, causing it to stop communicating on the network. A video on upgrading the related HMI module shows the module cluster, including the ASCM, is located behind the glove box.
   How to confirm: If the wiring, power, and grounds to the module are all confirmed to be good, but the module still won't communicate with a scan tool, the module itself is condemned. This is a process-of-elimination diagnosis.
   Typical fix: The module must be replaced and then programmed to the vehicle using specialized dealer-level software (SPS).
   Est. part cost: $150-$400
3. Low Battery Voltage or Poor Ground Connection ⚪ Low Probability Modern control modules are highly sensitive to system voltage. A weak battery, failing alternator, or corroded ground connection can cause intermittent communication dropouts and trigger U-codes across various systems.
   How to confirm: Test the battery's state of charge and health; it should be above 12.4V with the engine off. Check the alternator output (typically 13.5-14.5 volts with the engine running). Inspect and clean the main battery terminals and chassis ground points.
   Typical fix: Replace the weak battery, repair the charging system, or clean/tighten the ground connections.
   Est. part cost: $0-$250

Rare But Worth Checking

• Diagnostic Tool or Cable Fault: A specific GM Technical Service Bulletin (PIT5441C) warns technicians that a faulty MDI (Multiple Diagnostic Interface) or its cable can create false U0075 codes. The tool itself can cause the communication error it's supposed to be diagnosing because the fault lies in the tool's connection to the Object Detection Bus pins (3 and 11). This is a diagnostic artifact, not a vehicle fault.

Diagnosis Steps

1. Verify battery voltage is above 12.4V and the charging system is working correctly.
2. Use a professional scan tool (like the GM MDI) to check for codes in ALL vehicle modules. Note all U-codes present.
3. Attempt to communicate directly with the Active Safety Control Module (K118/K124).
4. If communication fails, inspect the Object Detection Bus circuits (often Tan/White and Tan wires) at the Data Link Connector (DLC) terminals 3 and 11 for proper resistance.
5. As per TSB PIT5441C, if multiple communication codes are present, test the diagnostic tool and cable on a known-good vehicle or with a loopback adapter to rule out a faulty tool causing false codes.
6. Locate the Active Safety Control Module. On the Acadia, it is located behind the glove box area.
7. Per TSB PIT5700B, inspect the wiring harness for an open circuit near splice JX300, located on the floor near the driver's seat.
8. Test for proper power and ground at the ASCM connector.
9. If wiring, power, and grounds are all good, the Active Safety Control Module is the most likely cause of the failure.

Parts You'll Likely Need

• Active Safety Control Module (OEM #84737638) — This module is the central controller for the affected safety systems. If it fails internally, it will stop communicating and set a U0075 code. This part number is superseded by or related to 84218070 and 84356794.
  Trusted brands: ACDelco, GM Genuine
  OEM price range: $150-$400
  Aftermarket price range: $150-$300
• Wiring Harness Connector Pigtail — If the connector at the module is corroded or damaged, replacing the connector pigtail is often the most reliable repair.
  Trusted brands: ACDelco, Dorman
  OEM price range: $40-$80
  Aftermarket price range: $20-$50

Related Codes That Often Appear With This One

• U026A — Loss of Communication with a specific ADAS sensor, often seen with U0075 as per TSB PIT5441C.
• U026B — Loss of Communication with a specific ADAS sensor, often seen with U0075 as per TSB PIT5441C.
• U026C — Loss of Communication with a specific ADAS sensor, often seen with U0075 as per TSB PIT5441C.

Technical Service Bulletins (TSBs) & Recalls

• PIT5441C: Details diagnostic steps for U0075 related to the Object Detection System and Active Safety Module, and warns of false codes from faulty diagnostic cables.
• PIT5700B: Identifies a specific wiring open-circuit location at splice JX300 near the driver's seat as a cause for ASCM communication loss on the same vehicle platform.

Platform-Specific Known Issues

• TSB #PIT5441C: This bulletin directly addresses U0075 on the 2017-2018 Acadia. It guides technicians to diagnose the Active Safety Module and warns that a faulty diagnostic interface cable (MDI) connected to DLC terminals 3 and 11 can falsely trigger this code.
• TSB #PIT5700B: While for slightly later models (2019-2020), this bulletin highlights a known issue with a wiring harness open circuit near the driver's seat at splice JX300 causing communication loss to the Active Safety Control Module. This is a highly relevant potential failure point for the 2017-2018 models due to the shared platform design.

Mechanic-Grade Diagnostic Values

• Object Detection CAN Bus Resistance — expected: Approximately 60 Ohms. Failure: A reading of ~120 Ohms indicates an open circuit or an offline terminating resistor (module). A reading near 0 Ohms indicates a short between the two CAN wires.
• ASCM Power Supply Voltage — expected: 12.2 - 12.8 V with ignition on. Failure: Voltage below 12V can cause communication dropouts.
• ASCM Ground Circuit Resistance — expected: Less than 0.2 Ohms. Failure: Resistance higher than 0.2 Ohms indicates a poor ground connection, which can cause intermittent module operation.

Hidden / Shadow Codes Worth Checking

• U0075 with Symptom Byte (e.g., U0075 02): GM uses a two-digit hexadecimal 'symptom byte' that provides more specific information. For example, '02' often indicates a 'short to ground', while other values could indicate an open circuit or invalid data. This provides a critical clue for diagnosis. (see via A dealer-level scan tool like the GM GDS2 is required to view these symptom bytes.)

Scan Tool Commands That Help

• GDS2 (GM Global Diagnostic System 2): Module Diagnostics > Active Safety Control Module > Configuration/Reset Functions — This menu is used after replacing the Active Safety Control Module (ASCM). It allows the technician to perform the necessary programming and setup procedures for the new module to communicate with the vehicle.
• GDS2 (GM Global Diagnostic System 2): Clear All DTCs — After a repair is performed, this function clears codes from all modules. It's important to use this after fixing a network issue to ensure all related history codes are erased.
• GDS2 (GM Global Diagnostic System 2): Data Bus Diagnostic Tool > Detected State > DLC Terminal 1 — This function, referenced in TSB PIT5700B, is used to see a list of all modules currently communicating on the Low-Speed CAN bus. If the K124 ASCM is missing from this list, it confirms it is offline.

Wiring & Ground Locations

• JX300 — On the floor near the driver's seat.. TSB PIT5700B identifies this splice pack as a common location for an open in circuit 5060 (Low Speed GMLAN), which directly causes the Active Safety Control Module (K124) to lose communication.
• K124 Active Safety Control Module — Located behind the glove box area.. This is the primary control module for the systems that are disabled when U0075 is set. All diagnostic paths lead to verifying its power, ground, and communication lines.
• Data Link Connector (DLC) Pins 3 & 11 — The diagnostic port under the driver's side dashboard.. These are the specific pins for the Object Detection Bus. A technician can measure the network's resistance here to quickly check its integrity. TSB PIT5441C also warns that faulty diagnostic tool cables can cause issues at these specific pins, creating a false U0075 code.

Real Owner Repair Stories

• South Main Auto Repair, YouTube (on a platform-mate 2015 GMC Acadia) (2015 GMC Acadia) — Instrument cluster going blank, multiple warning lights (engine, ABS, airbag), and both blind spot indicators on the mirrors staying illuminated.
  ❌ Tried (didn't work) The vehicle owner had another shop replace both side object detection modules, but the problem persisted.
  ✅ What actually fixed it The technician found severe corrosion inside the wiring connector for the left rear Side Object Detection Module (located in the bumper). The module itself was undamaged, but the connector pins were destroyed by water intrusion. Repairing the connector and wiring resolved the communication faults.

OEM Part Supersession History

• 84218070 → 84356794, 84737638 — Standard part revision and updates by the manufacturer.
  Heads up: These parts are listed as compatible replacements for the 2017-2018 Acadia Active Safety Control Module. However, replacement always requires dealer-level programming (SPS) to configure the module to the specific vehicle's VIN and options.