C1240 Steering Angle Sensor Overtravel Performance

C1240 Code - with ignition on, but not if a CAN time out failure is detected. Or, if a fault is detected by the Steering Angle Sensor. If the Antilock Brake System (ABS) Module detects that absolute value of the measured steering wheel angle is greater than 720 degrees.

Possible causes C1240 Code

• Vehicle  damage
• Steering column/Intermediate shaft damage
• Steering wheel alignment
• Steering angle sensor loose
• Clockspring (SAS) improperly installed (wrong mounting position)
• Clockspring (SAS)

Diagnose C1240 Code

Step 1. Perform test drive and verify DTC is still active

Turn the ignition on, with the scan tool erase ABS DTCs. Cycle the ignition switch. Turn steering wheel from lock to lock. With the scan tool, read ABS DTCs.

Does this DTC reset?

Yes, go to step 2.

No, go to ABS Intermittent condition.

Step 2. Check steering angle sensor output

Start the engine, center the steering wheel. With the scan tool, read the steering Angle sensor position.

Is the Steering Angle Sensor Position within ±15°?

Yes, go to step 4.

No, go to step 3.

Step. Inspect vehicle, Steering column, and Intermediate shaft for damage

If possible, check vehicle repair history for collision damage.

Turn the ignition off, inspect the vehicle for damage causing tracking problems or steering wheel misalignment. Inpspect the steering column and intermediate shaft for damage. Center the steering wheel, with the scan tool read the Steering Angle sensor position.

Is the Steering Angle Sensor Position within ±15°?

Yes, repair as necessary

No, go to step 4.

Step 4. Check Steering Angle change

Turn steering wheel so wheels point in a straight ahead position. With the scan tool check steering angle if reading travels to 720 degrees while rotating wheel from lock to lock (Sensor damage can occur if wheel is turned over 720 degrees). Rotate steering wheel to the right and the degrees will decrease and rotate steering wheel to the left and the degrees will increase.

Did the Steering angle change accordingly and display less than 720 degrees from lock to lock?

Yes, go  to step 5.

No, replace the Clockspring (SAS). Perform the ABS Verification Test.

Step 5. Check Clockspring (SAS) Installation

To avoid serious or fatal injury on vehicles equipped with airbags, disable the Supplemental Restraint System (SRS) before attempting any steering wheel, steering column, airbag, seat belt tensioner, impact sensor, or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the SRS. Failure to take the proper precautions could result in accidential airbag deployment.

Proper Clockspring (SAS) installation is crucial for proper operation. Verify that the Clockspring (SAS) is properly installed.

Is the Clockspring (SAS) properly installed?

Yes, replace the Clockspring (SAS) and clear offsets by initializing ECU with wheels pointing straight ahead. Perform the ABS Verification Test.

No, repair as necessary and clear offsets by initializing ECU with wheels pointing straight ahead. Perform the ABS Verification Test.

Share this post