U0075 on 2017-2018 Chevrolet Volt: Active Safety Communication Fault Causes and Fixes

What's Unique About the 2017-2018 Chevrolet VOLT

For the second-generation Volt, the U0075 code is closely tied to the advanced driver-assistance systems (ADAS). A GM Technical Service Bulletin (TSB #PIT5441C) directly links this code to a fault within the Active Safety Module's communication circuit, which utilizes pins 3 and 11 on the Data Link Connector (DLC). This makes it distinct from a general powertrain or body network failure. The issue is almost always localized to the specific wiring or modules involved in the driver-assist features, such as the forward camera or side radar sensors.

Diagnostic Flowchart

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

Symptoms You May Notice

• "Service Driver Assist System" message on the dashboard.
• Warning lights for Stabilitrak, ABS, or Traction Control may illuminate.
• Adaptive Cruise Control (ACC) becomes inoperative.
• Blind-spot monitors and other object detection systems stop working.
• Check Engine Light may be illuminated.
• Red OnStar light may appear if the fault is widespread.

Most Likely Causes

1. Wiring Harness or Connector Issue 🔴 High Probability Wiring for safety system components, particularly for sensors located in the bumpers, is exposed to moisture, road debris, and potential physical damage, leading to corrosion or breaks. GM service manuals often instruct dealers to replace entire harnesses rather than attempt splices, especially after minor collisions, indicating the sensitivity of these circuits.
   How to confirm: Visually inspect the wiring harnesses and connectors going to the Active Safety Control Module and any related sensors (e.g., bumper-mounted object/radar sensors) for chafing, breaks, pinched wires, or corrosion. Pay close attention to connectors in the rear bumper area, as they are a common failure point on similar GM platforms.
   Typical fix: Repair the damaged section of the wiring harness or replace the affected connector pigtail. In some cases, a full harness replacement may be recommended by the dealer.
   Est. part cost: $25-$150
2. Faulty Active Safety Control Module (ASCM) 🟡 Medium Probability → Shop Active Safety Control Module Bracket Bolt Like any electronic component, the module can fail internally. On the Volt, this module is located in the rear of the vehicle, and while generally protected, water intrusion in the trunk/hatch area can lead to failure. A diagnostic scan showing the ASCM is offline while its power and ground are good points to internal failure.
   How to confirm: This requires a professional scan tool that can communicate with individual modules. If the ASCM is not responding or 'offline' while all other modules are communicating, and its power and ground connections are good, the module itself is likely faulty. A technician would verify power, ground, and network activity at the module's connector before condemning it.
   Typical fix: The module must be replaced and then programmed to the vehicle using GM's Service Programming System (SPS) software. The ASCM is located in the rear of the vehicle, often behind trim panels.
   Est. part cost: $150-$400
3. Weak or Failing 12V Battery ⚪ Low Probability → Shop Vehicle Battery Modern vehicles, especially complex ones like the Volt, are very sensitive to system voltage. A weak 12V battery can cause random, intermittent communication codes across various modules as they fail to initialize correctly during startup. Multiple forum users report that a hard reset by disconnecting the 12V battery can temporarily resolve various electronic gremlins, pointing to voltage sensitivity.
   How to confirm: Test the 12V battery with a digital multimeter or a dedicated battery tester. The voltage should be above 12.4V with the car off. Have it load-tested at an auto parts store to confirm its health. A failing 12V battery is a very common first sign of widespread, seemingly unrelated electrical issues on the Volt.
   Typical fix: Replace the 12V AGM battery located in the rear compartment. 🎬 Watch: Step-by-step guide to replacing your Volt's 12V battery.
   Est. part cost: $180-$250

Rare But Worth Checking

• Faulty Diagnostic Tool Cable: TSB #PIT5441C specifically warns technicians that a faulty Multiple Diagnostic Interface (MDI/MDI 2) cable on their own scan tool can cause this code to be set spuriously during diagnosis. The bulletin advises testing the MDI cable on a known-good vehicle or using a self-test adapter before proceeding with vehicle diagnostics.
• Poor Connection at Underhood Fuse Block: Service Update #16017 for 2016-2017 Volts addresses a condition where the positive battery cable terminal can be misaligned at the underhood fuse block. This poor connection can cause electrical arcing and intermittent voltage issues for various modules, potentially triggering communication codes.

Diagnosis Steps

1. Check the 12V battery first. Ensure it is fully charged and healthy. A weak battery is a common cause of random communication codes on the Volt and many owners report it as the fix for various electrical issues.
2. Connect a professional-grade scan tool capable of reading GM-specific codes from all modules (not just a basic OBD-II reader). Per TSB #PIT5441C, verify the diagnostic tool and its cable are functioning correctly to avoid a false diagnosis.
3. Attempt to communicate with every control module on the vehicle. Note which modules are not responding. For U0075, the Active Safety Control Module (ASCM, K124) is the primary suspect.
4. If the ASCM is not communicating, locate the module. On the Volt, it is typically in the rear of the vehicle behind trim panels.
5. Inspect the wiring and connectors at the ASCM for any visible damage, corrosion, or loose pins. Check for signs of water intrusion in the area.
6. Using a wiring diagram, check for proper power and ground at the ASCM connector with a digital multimeter. If power or ground is missing, trace that circuit to find the fault (e.g., blown fuse, broken wire, or a bad ground connection).
7. If power and ground are present, check the CAN bus wiring (Object Detection Bus on DLC pins 3 & 11). With the battery disconnected, measure the resistance between the two CAN bus wires at the diagnostic port or the module connector. You should typically see 60 ohms if the network and its two terminating resistors are intact.
8. If all wiring, power, and grounds are good, the Active Safety Control Module is the most likely culprit and will require replacement and programming.
🎬 Learn more about control module diagnostics and the programming process.

Parts You'll Likely Need

• Active Safety Control Module (OEM #84165186) — This module is the central hub for the driver-assist safety network. If it fails internally, it can bring down the entire network, triggering the U0075 code. This part is also referred to as an 'Extension' in some GM parts catalogs.
  Trusted brands: ACDelco, GM Genuine
  OEM price range: $250-$400
  Aftermarket price range: $150-$300
• 12V AGM Battery — A weak 12V battery can cause undervoltage conditions that lead to intermittent communication faults between modules. It's a common and relatively simple fix to rule out before more complex diagnostics.
  Trusted brands: ACDelco, Odyssey, NorthStar
  OEM price range: $220-$280
  Aftermarket price range: $180-$250

Related Codes That Often Appear With This One

• U026A, U026B, U026C, U0265, U0268, U0269 — These are all communication loss codes for various components within the Active Safety System, such as the side object sensors and front camera. TSB #PIT5441C groups them with U0075 as being related to the same core issue on the Object Detection Bus.

Technical Service Bulletins (TSBs) & Recalls

• PIT5441C: Mentions U0075 in relation to Object Detection System messages and advises technicians to inspect their diagnostic interface cable, indicating it can be a source of falsely set codes on the sensitive Object Detection Bus.

Platform-Specific Known Issues

• Owner Experience: Intermittent "Service Driver Assist" Message: A user on Reddit with a 2018 Volt reported the "Service Driver Assist System" message and inoperative Adaptive Cruise Control. A standard OBD2 scanner found no codes, highlighting the need for a more advanced tool that can read module-specific faults. This is a classic symptom presentation for the U0075 fault.
• Dealer Repair Story: Full Wiring Harness Replacement: A Volt owner on Reddit described a situation where a dealer recommended replacing the entire engine wiring harness for an electrical issue on a 2017 model. Another user noted that official factory service manuals sometimes deem specific harness branches non-repairable, forcing a full replacement. This underscores the complexity and high repair cost potential for wiring faults on this vehicle.

Mechanic-Grade Diagnostic Values

• Object Detection CAN Bus Resistance — expected: ~60 Ω. Failure: A reading of ~120 Ω indicates an open circuit or a missing terminating resistor. A reading near 0 Ω indicates a short between the CAN High and Low wires.
• Object Detection CAN Bus Voltage (Key On) — expected: CAN High (Pin 11 to ground): ~2.7V. CAN Low (Pin 3 to ground): ~2.3V.. Failure: Voltages that are stuck high, low, or at 2.5V on both lines indicate a short or open circuit.

Scan Tool Commands That Help

• GM GDS2 / SPS (Service Programming System): K124 Active Safety Control Module: Programming and Setup — This function is mandatory after replacing the Active Safety Control Module (ASCM). It programs the new module with the vehicle's VIN and correct software calibration, without which the module will not function correctly.

Wiring & Ground Locations

• K124 Active Safety Control Module — In the rear compartment, on the driver's side, behind the trim panel. It is often located near the 12V battery.. This is the master module for the Object Detection Bus. All diagnostic paths for U0075 lead here. Physical inspection for water intrusion or connector damage is critical.
• X84 Data Link Connector (DLC) — Under the driver's side dashboard, to the left of the steering column.. This is the primary access point for diagnosis. The Object Detection Bus is on Pins 3 (CAN Low) and 11 (CAN High), which is different from the main high-speed bus on Pins 6 and 14.
• G402 — In the rear compartment area, typically on the body structure near other electronic modules.. This is a major ground point for several rear-mounted electronic modules, including potentially the ASCM. A loose or corroded G402 ground can cause intermittent communication failures and codes like U0075.

Real Owner Repair Stories

• gm-volt.com forum user (2017 Chevrolet Volt) — Service Driver Assist message, multiple U-codes including U0075.
  ❌ Tried (didn't work) Replacing the 12V battery.
  ✅ What actually fixed it The dealer diagnosed a faulty Active Safety Control Module (ASCM). The owner replaced the module (Part #84165186) themselves, then had the dealer perform the mandatory online programming via SPS (Service Programming System) to link the new module to the car. The final cost was the part plus one hour of dealer labor for programming.
• Reddit user r/volt (2017 Chevrolet Volt) — "Service Driver Assist" message and U0075 after a minor rear-end collision.
  ❌ Tried (didn't work) Clearing codes.
  ✅ What actually fixed it A body shop had improperly reconnected or damaged the wiring harness for the rear bumper sensors during the initial repair. The final fix was to correctly repair and secure the harness connector for the side object detection sensors, which are on the same network as the ASCM.

OEM Part Supersession History

• 84165186 → 84531050, 84991870 — Part revision and consolidation by the manufacturer.
  Heads up: The new part number is the correct service replacement. Always verify the latest part number with a GM dealer using the vehicle's VIN before ordering. Programming is required for all versions.