U0415 on 2015-2017 GMC Sierra: Invalid ABS Data Causes & Fixes

What's Unique About the 2015-2017 Gmc SIERRA

For this generation of GMC Sierra (K2XX platform), U0415 is frequently caused by issues external to the ABS module itself. Multiple GM Technical Service Bulletins (TSBs) point to specific, well-documented problems. The most common culprits are either a low brake fluid level causing the sensor to send erratic signals during vehicle motion (TSB #PIT5490B), or specific wiring harnesses being pinched, chafed, or corroded in known locations like under the door sill plates (TSB #PIT5457D) and behind the instrument panel (TSB #PIT5288E). Another significant, documented cause is a poor connection at the G218 body ground point.

Diagnostic Flowchart

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

Symptoms You May Notice

• ABS warning light on
• Traction Control or Stabilitrak warning light on
• "Service Stabilitrak" message in the driver information center (DIC)
• "Service Trailer Brake" message in the DIC
• "Steering Assist is Reduced Drive With Care" message
• Cruise control is inoperative
• Steering wheel jerks or kicks back
• Instrument panel, radio, or HVAC display goes blank or flickers
• Engine stall at low speeds
🎬 Watch: Fixing flickering displays and stalling caused by poor grounds.

Most Likely Causes

1. Low Brake Fluid Level 🔴 High Probability → Shop Brake Fluid According to GM TSB #PIT5490B, the fluid level sensor is sensitive. Fluid sloshing in a reservoir that is near the 'MIN' line can cause the sensor to send intermittent 'low' signals during turns, braking, or acceleration. The EBCM broadcasts this data, and the Chassis Control Module (CCM) flags it as invalid, setting U0415 and the 'Service Trailer Brake' message.
   How to confirm: Visually inspect the brake fluid level in the master cylinder reservoir. If it is near or below the 'MIN' line, this is the likely cause. A professional scan tool can also monitor the 'Brake Fluid Level Sensor' parameter in the EBCM data, which will toggle between 'OK' and 'Low'.
   Typical fix: Top off the master cylinder with the correct DOT-rated brake fluid to the 'MAX' line. It is also critical to inspect for the cause of the low fluid, such as worn brake pads or a leak.
   Est. part cost: $5-$15
2. Damaged or Corroded Wiring Harness Under Sill Plates 🟡 Medium Probability TSB #PIT5457D specifically calls out that the wiring harness running in the channel under the driver and passenger door sill plates is susceptible to moisture intrusion. This leads to corrosion and opens/shorts on the Communication Enable circuit (5986), disrupting communication with the EBCM and other modules.
   How to confirm: Remove the driver and passenger sill plates and peel back the carpet to inspect the wiring harness channel for signs of water, corrosion (green or white powder on wires/connectors), or physical damage. Splice J365 under the passenger sill plate is a known point of failure.
   Typical fix: Repair the damaged section of the wire. This involves cutting out the corroded section, splicing in a new piece of wire (GM recommends crimp connectors over solder), and protecting the repair with heat-shrink tubing.
   Est. part cost: $5-$25
3. Poor Body Ground (G218) 🟡 Medium Probability TSB #PIT5405C identifies a poor connection at ground G218 as a cause for a multitude of communication codes and bizarre electrical symptoms, including U0415. The factory sound-deadening insulation often gets trapped under the ground terminal during assembly, preventing a solid connection to the body. 🎬 See how to locate and clean the G218 ground point.
   How to confirm: Locate ground G218 on the driver's side, under the dash near the A-pillar and speaker. Check if the nut is loose or if the black insulation material is caught under the terminal's eyelet.
   Typical fix: Remove the nut and ground terminal, trim away any interfering insulation, clean the contact surfaces of the stud and eyelet with a wire brush, and securely retighten the nut.
   Est. part cost: $0
4. Pinched Wire Harness in Instrument Panel ⚪ Low Probability TSB #PIT5288E (and later versions) notes that the wire harness to the left of the instrument panel (near the fuse block/parking brake) can become pinched against a metal bracket, causing various electrical faults and communication codes.
   How to confirm: Inspect the wiring harnesses around the left side of the dash and near the parking brake mechanism for any signs of being pinched, chafed, or damaged by sharp metal edges.
   Typical fix: Repair the damaged wires and re-route or protect the harness to prevent future pinching.
   Est. part cost: $5-$25

Rare But Worth Checking

• Failing Electronic Brake Control Module (EBCM): → Shop ABS Control Module While possible, module failure is far less common than wiring or fluid level issues on this platform. The EBCM should only be suspected after all wiring, ground, and fluid level causes have been thoroughly ruled out. A replacement module requires programming to the vehicle's VIN.
• Weak or Failing Battery: → Shop Vehicle Battery Low system voltage from a weak or failing battery can cause unpredictable behavior and communication errors between modules during startup or under load. If the battery is old or has trouble starting the engine, it should be tested with a load tester.

Diagnosis Steps

1. Check the brake fluid level in the master cylinder. Top it off to the 'MAX' mark if it is low. Clear codes and re-test. This is the simplest and a very common fix per TSB #PIT5490B.
2. If the fluid level is OK, perform a full vehicle scan with a tool that can read all modules (BCM, CCM, EBCM, etc.). Note all other codes present, especially communication (U-prefix) codes.
3. Inspect ground G218, located under the driver's side dash near the A-pillar speaker. Ensure the nut is tight and that no insulation is trapped under the terminal, as per TSB #PIT5405C.
4. Remove the driver and passenger side door sill plates and inspect the wiring harnesses in the channels for corrosion, moisture, or damage, paying close attention to the Communication Enable circuit (5986), as per TSB #PIT5457D.
5. Inspect the wiring harness near the left side of the instrument panel and parking brake pedal for signs of being pinched or chafed, as per TSB #PIT5288E.
6. Test the battery and charging system. Low system voltage can cause a wide range of communication faults.
7. If all wiring and grounds appear intact, use a professional scan tool to monitor the live data from the EBCM, specifically the 'Brake Fluid Level Sensor' parameter, to check for intermittent signals while driving.
8. If all external factors are ruled out, the EBCM itself may be faulty. This should be the last step in diagnosis.

Parts You'll Likely Need

• Brake Fluid (DOT 3) (OEM #ACDelco 19353461 (DOT 3)) — Low brake fluid is a high-probability cause for U0415 on this truck, often accompanied by a 'Service Trailer Brake' message, as detailed in TSB #PIT5490B.
  Trusted brands: ACDelco, Prestone, Bosch
  OEM price range: $10-$20
  Aftermarket price range: $5-$15
• Electronic Brake Control Module (EBCM) (OEM #23380704 (Note: Part number can vary by VIN and options like brake type (JD9). Always verify with a dealer)) — This is the part to replace if all wiring, ground, and input issues have been ruled out. It is the source of the invalid data. Replacement requires programming.
  Trusted brands: ACDelco (GM Genuine)
  OEM price range: $200-$450

Related Codes That Often Appear With This One

• U0121 — Often appears with U0415 as both relate to communication issues with the EBCM. U0121 indicates a complete loss of communication, while U0415 indicates the data is present but invalid. They can share the same root cause, like a damaged wire in the sill plate harness.
• U0073 — This is a general 'Control Module Communication Bus A Off' code. It often sets alongside U0415 when a wiring or ground issue (like at G218) disrupts the entire communication network.
• C0710 — Relates to the steering position sensor. It can be set along with U0415 due to the same underlying electrical issues (bad ground G218, pinched harness) that affect multiple systems.

Technical Service Bulletins (TSBs) & Recalls

• PIT5457D: Loss of communication with EBCM, SWPS, PSCM, and/or SCM due to wiring issues under sill plates.
• PIT5405C: Various electrical issues and DTCs caused by a poor BCM ground at G218.
• PIT5288E: Various electrical issues and DTCs caused by a pinched wire harness in the left instrument panel.
• PIT5490B: Service Trailer Brake message with DTC U0415 caused by low brake fluid level.

Platform-Specific Known Issues

• TSB #PIT5490B: Details how a low brake fluid level can cause fluid slosh during maneuvers, momentarily tripping the level sensor. The Chassis Control Module then flags this intermittent data from the EBCM as invalid, setting U0415 and a 'Service Trailer Brake' message.
• TSB #PIT5457D: Documents that loss of communication codes, including U0415, can be caused by damaged or corroded wiring in the harness located under the driver and passenger sill plates. It specifically calls out checking the Communication Enable circuit 5986.
• TSB #PIT5405C: Points to a poor connection at body ground G218 as a potential cause for a wide range of electrical issues and communication DTCs, including U0415. The issue is often sound deadening material trapped under the ground terminal.
• TSB #PIT5288E: Identifies a pinched wire harness in the left instrument panel area near the parking brake as a cause for U0415 and other electrical faults.

Mechanic-Grade Diagnostic Values

• High-Speed CAN Bus Resistance — expected: 60 Ohms (+/- 5 Ohms). Failure: A reading of ~120 Ohms indicates an open circuit or one terminating resistor is offline. A reading significantly less than 60 Ohms (especially near 0) indicates the CAN High and CAN Low wires are shorted together.
• Communication Enable Circuit (5986) Voltage — expected: Approximately 12 Volts when the ignition is in ACC, ON, or START.. Failure: Low or no voltage indicates an open, short, or high resistance in the circuit, often under the sill plates. This circuit is low amperage; it should light a small test bulb (like a 194) but not a headlight. The BCM will shut down the circuit if it draws more than 0.88 amps.
• High-Speed CAN Bus Voltage (Active) — expected: CAN High (Pin 6 at DLC) should be ~2.5V at rest, driven to ~3.5V for a '0' bit. CAN Low (Pin 14 at DLC) should be ~2.5V at rest, driven to ~1.5V for a '0' bit.. Failure: Voltages that are stuck high, low, or do not change indicate a short to power, ground, or a module failure on the bus.

Scan Tool Commands That Help

• GDS2 (GM Dealer Scan Tool): Module Diagnostics > EBCM > Data Display — To monitor the live status of the 'Brake Fluid Level Sensor' parameter. Toggling between 'OK' and 'Low' while driving confirms the fluid sloshing issue described in TSB #PIT5490B.
• GDS2 (GM Dealer Scan Tool): Module Diagnostics > [Module Name] > Control Functions — Allows a technician to command specific outputs on and off to test functionality without physically accessing the component, which helps verify if a module is capable of controlling a circuit.
• GDS2 (GM Dealer Scan Tool): Vehicle DTC Information — To perform a full network scan of all modules on the vehicle to see which ones are communicating and what codes are stored in each. This is a critical first step to see the full scope of a communication issue.

Wiring & Ground Locations

• G218 — Driver's side, under the dash, near the A-pillar and the left-side speaker. Requires removal of the side dash panel and A-pillar trim.. This is a major body ground point. Factory-installed sound deadening material can get trapped under the ground lug, causing a poor connection. This intermittent ground disrupts communication for multiple modules, leading to a cascade of 'U' codes, including U0415, and other bizarre electrical symptoms.
• Circuit 5986 (Communication Enable) — This wire runs from the Body Control Module (BCM) to several other modules, including the EBCM. A known failure point is within the wiring channel located under the driver's and passenger's side door sill plates.. This circuit provides a 'wake-up' signal from the BCM to the EBCM. If the wire is open or has high resistance due to corrosion under the sill plate, the EBCM will not activate to communicate on the CAN bus, leading to codes U0121 and U0415.
• CAN Bus Terminating Resistors — Two 120-Ohm resistors are on the High-Speed CAN bus. One is internal to the Engine Control Module (ECM). The other is at the opposite end of the bus, often within another module or a dedicated connector.. The two resistors in parallel create the 60-Ohm resistance needed for proper signal integrity. If a wire breaks or a module containing a resistor fails, the total resistance will jump to 120 Ohms, disrupting communication and causing codes like U0415. This can be tested at pins 6 and 14 of the DLC.

Real Owner Repair Stories

• YouTube User Comment on 'G218 Ground Issue Fix' (2014-2018 Chevrolet Silverado/GMC Sierra (general)) — Randomly flickering dash and headlights, especially when braking or using turn signals. Progressed to the truck shutting off at low speeds, with 'park assist disabled' and 'power steering disabled' messages.
  ❌ Tried (didn't work) Having the battery and alternator tested (both were fine).
  ✅ What actually fixed it The issue was a poor ground at G218. Sound deadening material from the factory was trapped under the ground lug, causing an intermittent connection. Cleaning the ground and ensuring a solid metal-to-metal contact resolved all symptoms.

OEM Part Supersession History

• 23154722 → 23380704 — Standard part revision and update by the manufacturer.
  Heads up: The replacement module (23380704) requires programming and setup procedures using GM's GDS2 software to ensure it functions correctly with the specific vehicle's VIN and options.

Model Year Variations Within This Range

• 2016-2017: For 2016, the Sierra 1500 received a mid-cycle refresh with a new grille, headlights, and fascia. Apple CarPlay and Android Auto became available on the 8-inch screen. More significantly, a mild-hybrid 'eAssist' system became available on some 5.3L V8 models, which adds a small electric motor and a 0.45-kWh lithium-ion battery. While not a direct cause of U0415, this system adds complexity to the vehicle's electrical and charging systems.