U0126: Lost Communication With Steering Angle Sensor Module
Can disable stability control, ABS, and steering‑assist functions; steering feel may be altered or assist reduced
Overview
U0126 indicates a communication loss between the vehicle’s main control module and the steering angle sensor (SAS) module over the CAN bus, affecting ESC/ABS systems
Common Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- ABS and stability/ESC warning lights
- Reduced or intermittent power steering assist
- Steering feel abnormal or heavier than normal
Most Common Causes
Internal electronics failure or module not responding on the CAN bus
Wiring harness faults, loose pins, or corroded connections often interrupt communication
Low battery voltage, bad ground, or blown fuse can interrupt module operation
Open or shorted CAN high/low lines can prevent messages from transmitting
ECU/SAS firmware bugs or incomplete reprogramming may cause intermittent faults
Diagnostic Steps
-
Connect a professional OBD-II scan tool and read codes from all modulesExpected: U0126 present and possibly related U-codesInterpretation: Presence of additional communication codes suggests broader CAN network issues
-
Verify battery and charging system voltageExpected: 12.5V+ (off) and 13.5–14.5V (running)Interpretation: Low voltage indicates power supply issues that could cause communication dropout
-
Visually inspect SAS module wiring and connectorsExpected: No corrosion, secure pins, no insulation damageInterpretation: Corroded or loose connections likely interrupt CAN messaging
-
Test CAN bus lines for continuity and proper resistanceExpected: Approximately 60 ohms across CAN high/lowInterpretation: Significant deviation indicates short/open fault in CAN wiring
-
Attempt to communicate directly with the SAS module via scan toolExpected: Live data or module responsiveInterpretation: No communication indicates faulty module or wiring power issue
Repair Solutions
Properly secure connections and clean corrosion; gates and harness repairs vary by vehicle
OEM sensor replacement may require calibration with diagnostic tool
Includes battery service, fuse replacement, ground cleaning
Dealer or advanced diagnostic tool may be required
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Replacing SAS without checking wiring harness or power supply
- Assuming steering rack/mechanical issue instead of electrical communication fault
User Comments (0)
Share your experience or ask a question about this code.
Please login to post a comment.
Be the first to share your experience with U0126!