U0131 on 2015-2018 GMC Yukon: Lost Communication With Power Steering Control Module Causes and Fixes

What's Unique About the 2015-2018 Gmc YUKON

This generation of GMC Yukon and its sister platforms (Tahoe, Suburban, Silverado, Sierra, Escalade) are known for specific electrical vulnerabilities that trigger code U0131. GM has issued multiple Technical Service Bulletins (TSBs) pointing to poor ground connections (specifically G218 🎬 Watch: How to locate and fix the G218 ground connection.) and damaged wiring harnesses (Circuit 5986) as the primary culprits. These known issues often cause technicians to misdiagnose the problem as a failed power steering rack or module, when the fix is often a much simpler and cheaper wiring or ground repair. There was also a safety recall for some 2015 models for a defect that could cause a sudden loss of power steering assist, which could also present with a U0131 code.

Diagnostic Flowchart

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

Symptoms You May Notice

• Complete loss of power steering assist, making the wheel very hard to turn
• "Service Power Steering" message on the driver information center
• "Steering Assist is Reduced Drive With Care" message
• StabiliTrak warning light illuminated
• Multiple other warning lights may appear as network communication is disrupted (e.g., ABS, Traction Control)
• Steering wheel jerks or kicks back when turning
• In some cases, the engine may stall or the vehicle may not start
• Instrument panel cluster (IPC), radio, or HVAC display may go blank intermittently
• Headlights and dash lights flickering or dimming, especially when turning the wheel at low speeds

Most Likely Causes

1. Poor Body Control Module (BCM) Ground at G218 🔴 High Probability As documented in GM TSB #PIT5405C, the dash insulator mat can get trapped between the ground eyelet and the body stud, causing a poor connection. This poor ground can cause a host of electrical issues, including communication losses, especially when the electric power steering system draws a heavy load. This is a widely discussed issue in owner forums.
   How to confirm: Locate ground G218 on the driver's side, near the A-pillar behind the dash trim, often near the speaker. Check if the nut is loose or if the sound-deadening mat is visibly interfering with the connection. A voltage drop test across the ground can confirm high resistance. A visual inspection often reveals the problem.
   Typical fix: Remove the 10mm nut, trim away the interfering mat, clean the contact surfaces of the eyelet and body stud with an abrasive pad, and securely retighten the ground nut.
   Est. part cost: $0-$5
2. Damaged Wiring in Sill Plate Harness 🔴 High Probability GM TSB #PIT5457C (and subsequent revisions) identifies that the communication enable circuit (Circuit 5986) can develop high resistance or an open circuit in the wiring harness located under the driver's and/or passenger's door sill plates. This directly interrupts the 'wake up' signal to the PSCM and other modules, causing communication loss.
   How to confirm: Remove the sill plates and inspect the wiring harness for any signs of damage, corrosion, or pinched wires. A technician can test the voltage of Circuit 5986 (a low amperage 12V signal) at the PSCM connector. If voltage is low or absent when the ignition is on, the circuit is compromised.
   Typical fix: Repair the damaged section of the wire (Circuit 5986), ensuring a solid, insulated connection. In some cases, a splice (like Splice J365 under the passenger sill plate) may be the point of failure.
   Est. part cost: $5-$50
3. High Resistance in Battery Cables or Poor Connections 🟡 Medium Probability → Shop Vehicle Battery Another issue noted in GM bulletins (like 20-NA-113) is high resistance in the main battery cables, particularly the negative cable. This can cause system-wide low voltage, leading to random communication DTCs, especially when the electric power steering motor demands high current (e.g., during low-speed turns). Forum users have confirmed that replacing a faulty negative battery cable resolved widespread electrical issues.
   How to confirm: Perform a loaded voltage drop test on the positive and negative battery cables while cranking the engine. Voltage drop should not exceed 200mV on the negative side or 100mV on the positive side. Visually inspect cable ends for corrosion and ensure all connections at the battery, fuse block, and engine block are clean and tight.
   Typical fix: Replace the faulty battery cable(s), most commonly the negative cable. Clean all connection points thoroughly. Ensure the new cable clamps are properly seated on the battery posts.
   Est. part cost: $50-$200
4. Failed Power Steering Control Module (PSCM) / Rack Assembly ⚪ Low Probability → Shop Power Steering Control Module While less common than wiring issues, module failure can occur. A safety recall (#14743B) was issued for some 2015 models due to a defect in the power steering assist motor, which is part of the assembly. Additionally, a calibration error noted in TSB 20-NA-113 could cause DTCs to remain current, misleading technicians into thinking there's an active fault when there isn't.
   How to confirm: This should only be suspected after all wiring, grounds, and power feeds to the module have been tested and confirmed to be good. A scan tool will show the PSCM as offline and unresponsive. Before replacement, a technician should check if a PSCM reprogramming is applicable.
   Typical fix: Replace the entire steering rack assembly, which includes the integrated PSCM and motor. The new module will require programming to the vehicle.
   Est. part cost: $800-$2000

Rare But Worth Checking

• Blown Fuse for PSCM: The PSCM is protected by a large 80A or 100A fuse, typically located in the battery fuse block on top of the battery. While not common to fail on its own, a short circuit in the power feed wire or an internal rack failure could cause it to blow.
• Aftermarket Device Interference: Poorly installed aftermarket devices like remote starters or insurance tracking dongles plugged into the OBD-II port can interfere with CAN bus communication and trigger various U-codes. GM has issued bulletins advising to remove these devices as a first step in diagnosis.
• PSCM Calibration Error: Per GM TSB 20-NA-113, a software glitch can prevent the PSCM from clearing old fault codes, making them appear as current faults on every startup. This can cause a "Service Power Steering" message even if the original problem is gone. The fix is to reprogram the PSCM with updated software.

Diagnosis Steps

1. Scan all vehicle modules for DTCs to see which other modules are reporting communication loss. Note all current and history codes. Pay attention to codes that are also listed in TSBs like PIT5405C and PIT5457C.
2. Inspect the main battery connections. Ensure they are clean, tight, and that the cable clamps are not bottomed out. Per TSB PIT5405C, the posts should protrude 1-2mm above the clamps.
3. Locate and inspect ground G218. Remove the driver's side A-pillar and dash-end trim. The ground is a 10mm nut on a stud, often obscured by an insulation mat. Confirm the nut is tight and the insulation is not pinched under the eyelet.
4. Remove the driver and passenger sill plates and visually inspect the wiring harnesses for pinching, corrosion, or other damage as per TSB PIT5457C. Pay close attention to the Communication Enable wire, Circuit 5986.
5. If no obvious visual issues are found, perform a loaded voltage drop test on the main battery cables while an assistant cranks the engine. A reading over 200mV on the negative cable or 100mV on the positive cable indicates a bad cable.
6. Check the large fuse for the PSCM (80A or 100A) located in the fuse block on top of the battery.

Parts You'll Likely Need

• Wiring Repair Supplies — Often the fix is repairing a damaged wire in the sill plate harness or cleaning a ground connection.
  OEM price range: $5-$20
  Aftermarket price range: $5-$20
• Negative Battery Cable (OEM #84634109) — The main battery ground cable can develop high resistance, causing widespread electrical issues. Replacing it is a common fix for various communication codes. This part number supersedes several previous numbers.
  Trusted brands: ACDelco
  OEM price range: $90-$190
  Aftermarket price range: $40-$80
• Power Steering Rack and Pinion Assembly (OEM #86553005) — This is the component to replace if all wiring and ground issues have been definitively ruled out. On these GM vehicles, the module is integrated with the steering rack and not typically serviced separately.
  Trusted brands: ACDelco (GM Original Equipment), BBB Industries (Remanufactured), Carquest (Remanufactured)
  OEM price range: $1900-$2500
  Aftermarket price range: $950-$1300

Related Codes That Often Appear With This One

• U0121 — Lost Communication With Electronic Brake Control Module (EBCM). This often sets with U0131 because both modules are on the same communication bus and are affected by the same wiring/ground issues described in TSBs PIT5457C and PIT5405C.
• U0077 — Chassis Expansion Bus Off. This is a general network code indicating a major fault on the chassis CAN bus, which would include the PSCM and EBCM. It is explicitly mentioned in TSB PIT5457C.
• U0415 — Invalid Data Received From Electronic Brake Control Module. This indicates that even if communication isn't completely lost, the data being received is corrupt, often due to low voltage or a poor connection. It is listed in TSBs PIT5405C and 20-NA-113.
• U0428 — Invalid Data Received From Steering Angle Sensor Module. The steering angle sensor works closely with the power steering system, and network faults often affect them together. It is listed in TSB PIT5405C.
• C0544 — Steering Wheel Torque Sensor Circuit. This code is often triggered by the same electrical issues (low voltage, bad grounds) that cause the U0131 communication code, as noted in TSB PIT5405C.

Technical Service Bulletins (TSBs) & Recalls

• PIT5457C: Service ABS / TCS / Power Steering and/or Suspension Message, lists U0131 as a possible code caused by high resistance in the communication enable circuit under the sill plates.
• PIT5405C: Steering Jerks Or Kicks Back / Reduced Power Steering Assist / Engine Stall / No Start, lists U0131 as a possible code caused by a poor BCM ground at G218 or other power/ground cable issues.

Platform-Specific Known Issues

• Owner Experience: G218 Ground Fix: An owner on a Silverado forum described intermittent flickering lights, disabled park assist, and loss of power steering. After testing the battery and alternator, research pointed to the G218 ground. The fix involved removing the driver's side dash trim, locating the ground stud by the speaker, finding the insulation mat interfering with the connection, trimming the mat, and tightening the 10mm nut. This resolved all electrical issues.
• Owner Experience: Negative Battery Cable Failure: → Shop Vehicle Battery On TahoeYukonForum.com, a user reported a dashboard full of service warnings and intermittent power steering loss. After a shop initially blamed a loose terminal, the owner replaced the entire negative battery cable assembly themselves, which permanently fixed the problem. Another user found the crimp on the ground wire where it bolts to the engine block had failed inside the loom, causing intermittent issues until it was cut back and re-terminated.
• TSB Deep Dive: Circuit 5986 in Sill Plate: TSB PIT5457D details that the Communication Enable Circuit (5986) is a low-amperage (less than 0.88 amps) 12V signal from the BCM that 'wakes up' modules like the PSCM. The bulletin identifies common failure points for this wire under the driver's sill plate, the passenger's sill plate (at splice J365), and on short-wheelbase SUVs, where the harness can be pinched between the body and spare tire crossmember.

Mechanic-Grade Diagnostic Values

• Communication Enable Circuit (5986) Voltage — expected: Approximately 12 volts when the ignition is in ACC, ON, or START. Should be able to light a small bulb like a 194.. Failure: Low or no voltage at the PSCM connector indicates an open or high resistance in the circuit, often under the sill plates. Voltage below 11V when load-tested with a 194 bulb (approx. 250mA draw) points to high resistance.
• Negative Battery Cable Voltage Drop — expected: Less than 200 mV while cranking the engine with the fuel system disabled.. Failure: A reading above 200 mV indicates high internal resistance, requiring cable replacement.
• Positive Battery Cable Voltage Drop — expected: Less than 100 mV while cranking the engine with the fuel system disabled.. Failure: A reading above 100 mV indicates high internal resistance, requiring cable replacement.
• CAN Bus Resistance — expected: Approximately 60 Ω (Ohms) when measured between Pin 6 and Pin 14 of the DLC with the key off.. Failure: A reading significantly higher than 60 Ω suggests an open circuit or missing termination resistor. A reading lower than 60 Ω suggests a short between the CAN lines.

Scan Tool Commands That Help

• GDS2 (GM Global Diagnostic System 2): Power Steering Control Module Programming and Setup — This function is required after replacing the power steering rack and pinion assembly (which includes the PSCM). The new module must be programmed to the vehicle's VIN and calibrated for the specific options.
• GDS2 (GM Global Diagnostic System 2): Clear All DTCs — After performing a repair, such as fixing a ground or wiring issue, a full-system code clear is necessary. Some communication codes may not clear with a generic scanner and require the factory tool.

Wiring & Ground Locations

• G218 — Driver's side, behind the end-cap trim of the dashboard, near the A-pillar and speaker. It is a nut on a stud that grounds multiple components, including the BCM.. This is a primary failure point identified in TSB PIT5405C. The dash insulation mat often gets trapped under the ground's eyelet, causing high resistance and leading to numerous communication codes, including U0131.
• Circuit 5986 (Communication Enable) — This wire runs from the BCM to several modules, including the PSCM. It is routed in the harness under the driver's and passenger's side door sill plates.. This circuit acts as a 'wake-up' signal. TSB PIT5457C notes that this wire is prone to developing an open or high resistance in the sill plate area, which prevents the PSCM from activating and communicating.
• Splice J365 — Located in the wiring harness under the passenger's front sill plate.. This is a known splice point for Circuit 5986. A failure or corrosion at this splice can cause an open in the communication enable circuit, leading to code U0131.
• G110 — On the driver's side of the engine block, near the front, behind the power steering pump.. This is a common ground point for the Engine Control Module (ECM) and Transmission Control Module (TCM). While not directly for the PSCM, a poor connection here can disrupt the entire vehicle network, causing widespread communication codes including U0100, U0101, and potentially U0131 as a secondary fault.
• PSCM Main Connector — On the electric power steering rack and pinion assembly, under the vehicle.. This is the final destination for power, ground, and communication wires. Technicians must verify power, ground, and the 12V signal on Circuit 5986 at this connector to confirm if the fault is in the vehicle wiring or the module itself.

Real Owner Repair Stories

• Reddit user on r/ChevyTahoe (2015 Tahoe LTZ) — Intermittent cascade of warnings: Stabilitrak, suspension, trailer brake, and loss of power steering. Also, instrument panel lights (parking brake, ABS, traction control) would illuminate. The issue was intermittent and could sometimes be resolved by waiting and restarting the vehicle.
  ❌ Tried (didn't work) Replaced battery, Cleaned corroded connectors and wires, Replaced a wiring harness and the trailer brake module
  ✅ What actually fixed it The dealer identified that the negative battery cable was drawing too much power and replaced it. Although the owner reported the issue returned a day later, this repair points directly to the high-resistance battery cable issue identified in GM bulletins.
• YouTube channel "dpturner486" (2014-2018 Silverado/Sierra platform) — Headlights and dash lights flickering, especially when braking or turning. Eventually progressed to the truck shutting off completely during low-speed turns, loss of electric power steering, and multiple dash warnings like "park assist disabled".
  ❌ Tried (didn't work) Tested alternator and battery, which both checked out as fine.
  ✅ What actually fixed it The problem was the G218 ground on the driver's side dash. Sound deadening material was trapped under the ground connector. Trimming the material away and re-securing the ground nut permanently fixed all electrical issues.

OEM Part Supersession History

• 23207196 → 84423833, 84634523, 85126131, 85586221 (multiple supersessions) — Part has been updated or revised by the manufacturer over time.
  Heads up: The steering rack assembly for 2015-2016 models is different from the one for 2017-2020 models. It is critical to order the part based on the vehicle's specific VIN.
• N/A → 84634109 (AC Delco) — Updated design to address high resistance issues.
  Heads up: This is the negative battery cable for 2015-2020 models. Replacing this part is a common fix for widespread, intermittent electrical issues.

Model Year Variations Within This Range

• 2018+: Some later models in this generation, particularly Denali trims, began to be equipped with a 10-speed automatic transmission instead of the 6-speed. While not directly related to the PSCM, software and module calibrations can differ between these powertrain configurations.
• 2015: Early 2015 models were subject to a specific recall and several TSBs related to power steering software and hardware that were addressed in later production years. For example, one TSB mentions a ground stud issue specific to early 2015 models.