VSA DTC Troubleshooting: 28-120
DTC 28-120: Longitudinal Acceleration Sensor (Inside of Modulator-Control Unit) Stuck
NOTE:
Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
The yaw rate-acceleration sensor is built into the VSA modulator-control unit.
Before troubleshooting, check the VSA modulator-control unit for proper mounting. Improper mounting of the VSA modulator-control unit may set this code.

DTC Description
DTC
Freeze Frame
28-120 Longitudinal Acceleration Sensor (Inside of Modulator-Control Unit) Stuck
    

1.
Problem verification:

Problem verification
?1.
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?4.
Test-drive the vehicle at 6 mph (10 km/h) or more.
NOTE: Drive the vehicle on the road, not on a lift.

?5.
Check for DTCs with the HDS.
DTC Description
DTC
Freeze Frame
28-120 Longitudinal Acceleration Sensor (Inside of Modulator-Control Unit) Stuck
    

Is DTC 28-120 indicated?

     
YES
     
     
     
The failure is duplicated. Go to step 2.
     
NO
     
     
     
Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting.?
2.
Longitudinal acceleration sensor performance check:

Longitudinal acceleration sensor performance check
?1.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.
Test-drive the vehicle.
NOTE: Drive the vehicle on the road, not on a lift.

?3.
Check the parameter(s) below with the HDS.
Signal
Current conditions
Values
Unit
LONGITUDINAL ACCELERATION SENSOR
    

Does the indicated value change while accelerating or braking?

     
YES
     
     
     
The system is OK at this time.?
     
NO
     
     
     
Go to step 3.
3.
VSA modulator-control unit check (update):

VSA modulator-control unit check (update)
?1.
Update the VSA modulator-control unit if it does not have the latest software.

?2.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?3.
Test-drive the vehicle at 6 mph (10 km/h) or more.
NOTE: Drive the vehicle on the road, not on a lift.

?4.
Check for DTCs with the HDS.
DTC Description
DTC
Freeze Frame
     

Is DTC 28-120 indicated?

     
YES
     
     
     
Check for loose terminals in the VSA modulator-control unit 21P connector. If the VSA modulator-control unit was updated and the symptom/indication is still present, replace the VSA modulator-control unit.?
     
NO
     
     
     
Troubleshooting is complete. If any other DTCs are indicated, go to the indicated DTCs troubleshooting.?