U0126 Lost Communication With Steering Wheel Angle Sensor Module (SAS)
OBD2 Error Codes

U0126 Lost Communication With Steering Wheel Angle Sensor Module (SAS)

U0126 Lost Communication With Steering Wheel Angle Sensor Module (SAS)

OBD-II DTC Datasheet

Lost Communication With Steering Angle Sensor Module (SAS)

What does this mean?

This is a generic communication system diagnostic trouble code that applies to most makes and models of vehicles. This code means the Multi-Axis Acceleration Sensor (MAS) module and other control modules on the vehicle are not communicating with each other.

The circuitry most commonly used for communication is known as Controller Area Bus communication, or simply the CAN bus. Without this CAN bus, control modules cannot communicate and your scan tool may not receive information from the vehicle, depending on which circuit is involved.

The SAS module is responsible for informing other modules on the CAN bus which position the steering wheel is in. This affects the operation of the steering system, changes in the suspension system and, most importantly, is necessary for Electronic Stability Control (ESC). ESC maintains the vehicle's stability in all driving conditions, whether on wet pavement or during aggressive driving.

Troubleshooting steps may vary depending on the manufacturer, the type of communication system, the number of wires, and the colors of the wires in the communication system.

symptoms

Symptoms of a U0126 engine code may include:

  • Malfunction Indicator Lamp (MIL) illuminated
  • ABS indicator is on
  • TRAC indicator is on (depending on the manufacturer)
  • ESP / ESC indicator is on (depending on the manufacturer)

reasons

Usually the reason for installing this code is:

  • Loss of power or ground to the SAS module (most common)
  • Open in CAN + bus circuit
  • Open in the CAN bus - electrical circuit
  • Short circuit to power in any CAN bus circuit
  • Short to ground in any CAN bus circuit
  • Rarely - the control module is faulty

Diagnostic and repair procedures

A good starting point is always to check the Technical Service Bulletins (TSB) for your particular vehicle. Your problem may be a known issue with a known manufacturer-released fix and could save you time and money while troubleshooting.

If your scan tool can access DTCs and the only code you are pulling from other modules is U0126, try accessing the steering wheel angle system module. If you can access the codes from the SAS module, then code U0126 is either intermittent or a memory code. If the codes for the SAS module cannot be accessed, then code U0126 set by other modules is active and the problem already exists.

The most common failure is a loss of power or ground.

Check all fuses supplying the SAS module on this vehicle. Check all grounds for the SAS module. Locate ground anchorage points on the vehicle and make sure these connections are clean and secure. If necessary, remove them, take a small wire bristle brush and baking soda / water solution and clean each one, both the connector and the place where it connects.

If any repairs have been made, clear the DTCs from memory and see if U0126 returns or you can contact the SAS module. If no code is returned or communication is restored, the problem is most likely a fuse / connection issue.

If the code returns, look for the CAN C bus connections on your specific vehicle, especially the SAS module connector. Disconnect the negative battery cable before disconnecting the connector on the LAS control module. Once detected, visually inspect the connectors and wiring. Look for scratches, scuffs, exposed wires, burn marks, or molten plastic. Disconnect the connectors and carefully inspect the terminals (metal parts) inside the connectors. See if they look burnt or have a green tint indicating corrosion. If you need to clean the terminals, use an electrical contact cleaner and a plastic bristle brush. Allow to dry and apply electrical grease where the terminals touch.

Perform these few voltage checks before connecting the connectors back to the SAS module. You will need access to a digital volt/ohmmeter (DVOM). Make sure you have power and ground on the SAS module. Access the wiring diagram and determine where the main power and ground supplies enter the SAS module. Connect the battery before continuing with the SAS module still disabled. Connect the red lead of the voltmeter to each B+ (battery voltage) power supply included in the SAS module connector, and the black lead of the voltmeter to a good ground (if unsure, battery negative always works). You see the battery voltage reading. Make sure you have a good reason. Connect the red lead of the voltmeter to the battery positive (B+) and the black lead to each ground circuit. Once again, you should see the battery voltage every time you connect. If not, repair the power or ground circuit.

Then check the two communication circuits. Locate CAN C+ (or HSCAN+) and CAN C- (or HSCAN - circuit). With the black wire of the voltmeter connected to a good ground, connect the red wire to CAN C+. With the key on and engine off, you should see about 2.6 volts with little fluctuation. Then connect the red wire of the voltmeter to the CAN C- circuit. You should see about 2.4 volts with little fluctuation. Other manufacturers show CAN C- at about 5V and an oscillating key with the engine off. Check your manufacturer's specifications.

If all tests pass and communication is still not possible, or you were unable to clear DTC U0126, the only thing that can be done is to seek help from a trained automotive diagnostician, as this will indicate a faulty SAS module. Most of these SAS modules need to be programmed or calibrated for the vehicle in order to be properly installed.

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NOTE. This information is provided for informational purposes only. It is not intended to be used as a repair recommendation and we are not responsible for any action you take on any vehicle. All information on this site is protected by copyright.

3 comment

  • claudio

    Hi, well, let's see my 2008 Ford Cmax, the engine fails. I put the auto diagnosis on it. It says cylinder one failure and I remove the cable and the engine fails. The steering angle failure appears and then I delete it, the code keeps coming out. DTC u0126.00.8A yesterday who could help me please.

  • Ahmed Al-Rifai

    I have the camaro's traction system malfunctioning. Sometimes the system fails and it flashes on the dashboard, and sometimes it turns on, and we don't know what's wrong.

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