C0455 on 2007-2011 GMC Sierra: Steering Angle Sensor Circuit Causes and Fixes

What's Unique About the 2007-2011 Gmc SIERRA

This generation of GM trucks (GMT900 platform) is well-known for having issues with the electrical connector for the steering angle sensor. Due to excessive clearance in the plastic housing and vibration, the connector can develop a loose fit or fretting corrosion on the terminals, leading to intermittent signal loss. Fretting corrosion appears as small, dark smudges on the electrical terminals. General Motors issued a Technical Service Bulletin (PI0639, later updated to PI0639D) that specifically advises against replacing the sensor itself, instead outlining a fix that 🎬 Watch: Step-by-step guide to replacing the steering wheel sensor. involves adding a shim and dielectric grease to the existing connector to tighten the connection and prevent future corrosion.

Diagnostic Flowchart

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

Symptoms You May Notice

• "Service StabiliTrak" message on the Driver Information Center (DIC)
• "Service Traction Control" message on the DIC
• StabiliTrak/Traction Control indicator light is on
• StabiliTrak and Traction Control systems are disabled
• ABS light may be on in some cases

Most Likely Causes

1. Loose or Corroded Steering Angle Sensor Connector 🔴 High Probability → Shop Steering Angle Sensor A known issue on the GMT900 platform where the connector has excessive clearance, leading to movement and fretting corrosion. This is documented in TSB PI0639D.
   How to confirm: Visually inspect the steering angle sensor connector at the base of the steering column for looseness, dark smudges (fretting corrosion), or damage. Wiggling the connector may cause the fault to appear or disappear. A scan tool may show intermittent loss of signal from the SAS.
   Typical fix: Apply dielectric grease (GM P/N 12377900) to the connector terminals and add an adhesive shim (Kent Automotive P/N P40100) to the connector housing to eliminate movement, as per TSB PI0639D. If this fails, the TSB suggests replacing the harness-side connector pigtail.
   Est. part cost: $5-$30
2. Faulty Steering Angle Sensor 🟡 Medium Probability → Shop Steering Angle Sensor While less common than the connector issue, the internal electronics of the sensor can fail over time. Owners often replace the sensor when the TSB fix for the connector would have sufficed.
   How to confirm: Use a capable scan tool to monitor the steering angle sensor's live data while turning the steering wheel. The reading should be smooth and change consistently. Jumps, freezes, or incorrect values (e.g., reading 360 degrees when straight) indicate a failed sensor.
   Typical fix: Replace the steering angle sensor. This requires removing the airbag and steering wheel. The new sensor must be calibrated using a scan tool.
   Est. part cost: $40-$150
3. Improper Steering Wheel Installation / Alignment ⚪ Low Probability Can occur after steering column repairs or a wheel alignment if the steering wheel is not perfectly centered when the tie rods are adjusted. The sensor may be installed 360 degrees off.
   How to confirm: If the code appeared immediately after a steering system repair or alignment, this is a likely cause. A scan tool will show a non-zero steering angle when driving straight. This is also mentioned as a possible cause in TSB PIT4225F.
   Typical fix: Perform a proper four-wheel alignment, ensuring the steering wheel is centered. Then, use a scan tool to recalibrate the steering angle sensor's zero point. In cases of incorrect installation, the steering wheel may need to be removed and re-indexed on the shaft.
   Est. part cost: $0-$150

Rare But Worth Checking

• Damaged Wiring Harness: Check for chafed or broken wires in the harness leading from the steering column to the Electronic Brake Control Module (EBCM), especially if other steering column repairs have been performed recently. TSB PI0639D suggests replacing the connector pigtail if the initial fix doesn't work.
• Faulty Electronic Brake Control Module (EBCM): This is very rare. The EBCM should only be considered after all other possibilities, including the sensor, connector, and wiring, have been definitively ruled out.
• Poor EBCM Ground (G218): A poor ground connection for the EBCM can cause a variety of chassis-related codes, including C0455. Inspecting and cleaning the main EBCM ground connection (often located on the frame rail near the module) is a valid diagnostic step if other causes are ruled out.

Diagnosis Steps

1. Read the trouble codes from the Electronic Brake Control Module (EBCM) using a scan tool capable of reading chassis ('C') codes. A standard engine code reader may not see this code.
2. Inspect the steering angle sensor's electrical connector, located on the steering column under the dash, for looseness or signs of fretting corrosion (dark smudges).
3. If the connector is loose or shows any sign of corrosion, perform the fix outlined in TSB PI0639D: apply dielectric grease and add an adhesive shim to tighten the connection.
4. Clear the codes and test drive the vehicle. Wiggle the steering wheel and connector to see if the code returns.
5. If the code returns, use a scan tool to view the live data from the steering angle sensor. Turn the steering wheel lock-to-lock and observe the angle readings. They should change smoothly and read near zero when the wheels are straight.
6. If the live data is erratic, frozen, or shows a large angle (e.g., 360 degrees) when straight, the steering angle sensor has likely failed and needs replacement.
7. If the sensor and connector are good, inspect the wiring harness between the sensor and the EBCM for any signs of damage or chafing.
8. If a new sensor is installed, perform the Steering Angle Sensor calibration procedure using a compatible scan tool. This step is critical for proper function.

Parts You'll Likely Need

• Steering Angle Sensor (OEM #19330108) — This is the second most common failure point after the connector. If the TSB connector fix doesn't work, the sensor itself is the next logical part to replace.
  Trusted brands: ACDelco, Dorman
  OEM price range: $80-$150
  Aftermarket price range: $40-$100
• Dielectric Grease (OEM #12377900) — Required to protect the electrical connector terminals from moisture and fretting corrosion, as specified in TSB PI0639D.
  Trusted brands: ACDelco, Permatex
  OEM price range: $15-$25
  Aftermarket price range: $5-$10
• Adhesive Back Shim Stock (OEM #Kent Automotive P40100) — Used to add tension to the steering angle sensor connector to prevent it from moving and losing connection, as specified in TSB PI0639D.
  Trusted brands: Kent Automotive
  OEM price range: $5-$15
  Aftermarket price range: $5-$15

Related Codes That Often Appear With This One

• C0710 — This code is also related to the steering angle sensor circuit and is frequently set along with C0455 for the same root causes, as noted in TSBs PI0639D and PIT4225F.

Technical Service Bulletins (TSBs) & Recalls

• PI0639D: Service StabiliTrak Message Displayed in DIC, StabiliTrak Indicator Light On, DTC C0455 and/or C0710 Set. This is the most current TSB. It advises adding a shim (Kent P40100) and dielectric grease (GM 12377900) to the sensor connector and explicitly states NOT to replace the sensor for this condition.
• PIT4225F: Mentions that C0455 can be set along with C0710 and to ensure the steering wheel is properly installed to the steering shaft after repairs.

Platform-Specific Known Issues

• A GM Technical Service Bulletin (PI0639C, later superseded by PI0639D) was issued specifically for the 2007-2011 Sierra and related models to address code C0455. The bulletin identifies the primary cause as excessive clearance and fretting corrosion in the steering angle sensor's electrical connector and provides a specific repair procedure that does not involve replacing the sensor.
• Owner experiences confirm the TSB fix is highly effective. Many owners on forums report successfully resolving the C0455 code by simply applying dielectric grease and shimming the connector, avoiding the cost of a new sensor.

Mechanic-Grade Diagnostic Values

• Analog Signal Voltage (via Scan Tool) — expected: Approximately 2.5V with the steering wheel centered. Should sweep smoothly from ~0.25V (full left turn) to ~4.75V (full right turn).. Failure: Voltage is stuck, jumps erratically, or does not change smoothly when turning the wheel.
• 5V Reference Voltage at Sensor Connector — expected: 4.8V - 5.2V. Failure: Voltage is significantly lower or higher than the expected range, or absent.
• Digital Phase A / Phase B Signals (via Scan Tool) — expected: Should toggle between HIGH and LOW as the steering wheel is turned. Each change represents one degree of rotation.. Failure: One or both signals are stuck on HIGH or LOW and do not change when the wheel is turned.

Hidden / Shadow Codes Worth Checking

• C0472 / C0473: These are Body Control Module (BCM) codes for the analog steering wheel position signal. A fault detected by the BCM can cause it to send a serial data message to the EBCM, which in turn sets the C0455 code. (see via A scan tool capable of reading Body Control Module (BCM) fault codes is required.)

Scan Tool Commands That Help

• Tech2 / GDS2 / Professional Aftermarket Scanners (e.g., Autel): Steering Wheel Angle Sensor Centering / Reset — This function is used to clear the old calibration values from the module's memory. It should be performed before the 'Learn' procedure.
• Tech2 / GDS2 / Professional Aftermarket Scanners (e.g., Autel): Steering Wheel Angle Sensor Learn / Calibration — This procedure is mandatory after replacing the steering angle sensor, performing a wheel alignment, or any repair that involves disconnecting the steering column. It teaches the EBCM the new straight-ahead position.

Wiring & Ground Locations

• Steering Angle Sensor Connector — Located on the steering column, under the driver's side dashboard.. This is the most common point of failure due to the fretting and corrosion issue described in TSB PI0639D. All electrical testing of the sensor circuit begins here.
• SAS Connector Pinout — At the sensor on the steering column.. Pin 1: Reference Voltage, Pin 2: Low Reference (Ground), Pin 3: Phase A Signal, Pin 4: Phase B Signal, Pin 5: Phase C Signal (Index Pulse), Pin 6: Analog Signal. Knowing the pinout is essential for testing voltage, ground, and signal integrity.
• K17 Electronic Brake Control Module (EBCM) — Typically mounted on the driver's side frame rail, below the driver's door area.. This module receives the signals from the SAS and sets code C0455. The wiring harness between the sensor and the EBCM can be a point of failure (chafing, breaks).
• G218 — A primary Body Control Module (BCM) ground point. A TSB for slightly later models (PIT5405C) shows it located on the A-pillar behind the dash, near the ground stud. Its exact location can vary slightly, but it is a key ground for the BCM which processes SAS data.. A poor connection at G218 can cause a wide range of electrical issues, including communication faults that can lead to C0455 being set. The TSB notes to check for the dash insulator mat being trapped under the ground eyelet.

Real Owner Repair Stories

• Tahoe Yukon Forum (GMC Yukon (year not specified)) — 'Service Stability' message with code C0455 after replacing the intermediate steering shaft.
  ❌ Tried (didn't work) The owner suspected the steering wheel was not held still during the repair.
  ✅ What actually fixed it The community diagnosed the issue as the steering wheel being reinstalled 360 degrees out of alignment. The fix was to have an alignment shop properly center the steering wheel relative to the road wheels and then perform a steering angle sensor recalibration.
• PerformanceTrucks.net forum user (2010 Chevy Avalanche (GMT900 platform)) — StabiliTrak system acting erratically, C0455 code found.
  ❌ Tried (didn't work) Preparing to replace the sensor.
  ✅ What actually fixed it The owner unplugged the sensor to read the part number and then plugged it back in. This action alone temporarily resolved the issue, strongly indicating the problem was a poor connection, exactly as described in the TSB, rather than a failed sensor.
• YouTube - BlueDriver user (2010 Chevy Avalanche) — Intermittent 'Service Stabilitrak' and 'Service Traction Control' lights with code C0455.
  ❌ Tried (didn't work) N/A
  ✅ What actually fixed it The owner found that simply clearing the code with a BlueDriver OBD2 scanner would resolve the issue for approximately 500 miles before it returned. This points to an intermittent fault, like the loose connector, not a hard failure of the sensor.

OEM Part Supersession History

• Varies by year → Varies by year — There were at least two different, non-interchangeable part numbers used for the steering angle sensor during the 2010 model year alone.
  Heads up: It is critical to verify the correct part number for the specific vehicle's VIN before ordering a replacement sensor. Installing the wrong part, even if it physically fits, will result in continued faults.