VSA DTC Troubleshooting: 25-121, 26-121, 28-121
DTC 25-121: Yaw Rate Sensor (Inside of Modulator-Control Unit) Output Signal Malfunction
DTC 26-121: Lateral Acceleration Sensor (Inside of Modulator-Control Unit) Output Signal Malfunction
DTC 28-121: Longitudinal Acceleration Sensor (Inside of Modulator-Control Unit) Output Signal Malfunction
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 these codes.

DTC Description
DTC
Freeze Frame
25-121 Yaw Rate Sensor (Inside of Modulator-Control Unit) Output Signal Malfunction
    
26-121 Lateral Acceleration Sensor (Inside of Modulator-Control Unit) Output Signal Malfunction
    
28-121 Longitudinal Acceleration Sensor (Inside of Modulator-Control Unit) Output Signal Malfunction
    

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 9 mph (15 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
25-121 Yaw Rate Sensor (Inside of Modulator-Control Unit) Output Signal Malfunction
    
26-121 Lateral Acceleration Sensor (Inside of Modulator-Control Unit) Output Signal Malfunction
    
28-121 Longitudinal Acceleration Sensor (Inside of Modulator-Control Unit) Output Signal Malfunction
    

Is DTC 25-121, 26-121, or 28-121 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.
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 9 mph (15 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 25-121, 26-121, or 28-121 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.?