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VSA DTC Troubleshooting: 51-12

DTC 51-12:
 Motor Drive Circuit Malfunction
  1. Turn the ignition switch to ON (II).
  1. Clear the DTC with the HDS.
  1. Turn the ignition switch to LOCK (0), then turn it to ON (II) again.
  1. Check the DTCs with the HDS.
Is DTC 51-12 indicated?
YES -
Go to Step 5 .
NO -
Intermittent failure, the system is OK at this time. Check for loose terminals at the VSA modulator-control unit 36P connector. Refer to intermittent failures troubleshooting.
  1. Turn the ignition switch to LOCK (0).
  1. Check the No. 58 (30 A) fuse in the under-hood fuse/relay box.
Is the fuse blown?
YES -
Go to Step 7 .
NO -
Reinstall the checked fuse, then go to Step 9 .
  1. Check for continuity between VSA modulator-control unit 36P connector terminal No. 13 and body ground.
Is there continuity?
YES -
Repair short to body ground in the wire between the No. 58 (30 A) fuse in the under-hood fuse/relay box and the VSA modulator-control unit.■
NO -
Install a new No. 58 (30 A) fuse in the under-hood fuse/relay box, then go to Step 10 .

  1. Measure the voltage between VSA modulator-control unit 36P connector terminal No. 13 and body ground.
Is there battery voltage?
YES -
Go to Step 11 .
NO -
Repair open in the wire between the No. 58 (30 A) fuse in the under-hood fuse/relay box and the VSA modulator-control unit.■
  1. Reconnect the VSA modulator-control unit 36P connector.
  1. Turn the ignition switch to LOCK (0), then turn it to ON (II) again.
  1. Check for DTCs with the HDS.
Is DTC 51-12 indicated?
YES -
Check for loose terminals in the VSA modulator-control unit 36P connector. If the VSA modulator-control unit was updated, substitute a known-good VSA modulator-control unit, then retest. If the VSA modulator-control unit was substituted, go to Step 1 .
NO -
If the VSA modulator-control unit was updated, troubleshooting is complete. If the VSA modulator-control unit was substituted, replace the original VSA modulator-control unit. If any other DTCs are indicated, go to the indicated DTCs troubleshooting.■