VSA DTC Troubleshooting: 21
DTC 21:
 Difference in Wheel Speed
  1. Check the all four tyres.
Are all four tyres the correct size and properly inflated?
YES -
Go to Step 2 .
NO -
Install the correct tyres or set the tyres to the correct pressure, and retest by test-driving.■
  1. Check the RF, LF, RR, LR WHEEL SPD in the VSA DATA LIST with the HDS.
Are all four the same indicated value?
YES -
Go to Step 3 .
NO -
  1. Check the all magnetic encoders on the wheel bearings or pulser on the hub bearing units.
Are they installed correctly and good condition?
YES -
Go to Step 4 .
NO -
Replace the wheel bearing(s) or the hub bearing unit(s), and recheck by test-driving.
  1. Swap the wheels and tyres with a known-good vehicle.
  1. Turn the ignition switch ON (II).
  1. Clear the DTC with the HDS.
  1. Test-drive the vehicle.
  1. Check for DTCs with the HDS.
Is DTC 21 indicated?
YES -
Check for loose terminals in the VSA modulator-control unit 46P connector. If necessary, substitute a known-good VSA modulator-control unit and retest.■
NO -
Install the original wheels and tyres onto the vehicle and retest. If it recodes, replace the problem tyres.■