DTC Troubleshooting: 30
DTC 30:
 Adaptive Cruise Control (ACC) Relay Circuit Malfunction
NOTE: Information marked with an asterisk ( *1 ) applies to RHD model, and asterisk ( *2 ) applies to LHD model.
  1. Check the brake lights without pressing the brake pedal.
Are the brake lights off?
YES -
Go to Step 12 .
NO -
Go to Step 2 .
  1. Check the brake lights without pressing the brake pedal.
Are the brake lights off?
YES -
Intermittent failure. The system is OK at this time. Check for loose or poor connections.■
NO -
Go to Step 4 .
Is the brake pedal position switch OK?
YES -
Go to Step 5 .
NO -
Is the relay circuit board OK?
YES -
Go to Step 6 .
NO -
Replace the under-hood fuse/relay box and recheck.■
  1. Disconnect the 4P connector from the brake pedal position switch.
  1. Check for voltage between the brake pedal position switch 4P connector No. 2 terminal and body ground.
Is there battery voltage?
YES -
Repair a short to power in the wire.■
NO -
Go to Step 8 .
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect the ACC unit 20P connector.
  1. Turn the ignition switch to ON (II).
  1. Check for voltage between the ACC unit 20P connector No. 1 terminal and body ground.
Is there battery voltage?
YES -
Repair a short to power in the wire between the ACC unit and the relay circuit board, or between the ACC unit and the brake lights circuits.■
NO -
Check for loose or poor connections. If OK, update the ACC unit, then recheck. If the ACC unit was update already, replace the ACC unit. ■
  1. Turn the main switch to ON.
  1. Check the brake lights with the brake pedal pressed.
Do the brake lights come on?
YES -
Go to Step 15 .
NO -
Go to Step 38 .
Is DTC 30 indicated?
YES -
Go to Step 16
NO -
Go to Step 21 .
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect the 20P connector from the ACC unit.
  1. Check for continuity between the ACC unit 20P connector No. 1 terminal and body ground.
Is there continuity?
YES -
Repair a short to ground in the wire between the ACC unit and the relay circuit board.■
NO -
Go to Step 20 .
  1. Check for continuity between the ACC unit 20P connector No. 1 terminal and relay circuit board 10P connector No. 8 terminal.
Is there continuity?
YES -
Check for loose or poor connections. If the connections are OK, update the ACC unit, then recheck. If the ACC unit was already updated, replace the ACC unit. ■
NO -
Repair an open in the wire between the ACC unit and the relay circuit board.■
Is the relay circuit board OK?
YES -
Go to Step 22 .
NO -
Replace the under-hood fuse/relay box and recheck.■
  1. Turn the ignition switch to ON (II).
  1. Check for voltage between the relay circuit board 10P connector No. 6 terminal and body ground.
Is there battery voltage?
YES -
Go to Step 24 .
NO -
Repair an open in the wire between the No. 12 (15 A) fuse in the under-hood fuse/relay box and the relay circuit board.■
  1. Check for voltage between the relay circuit board 10P connector No. 5 terminal and body ground.
Is there battery voltage?
YES -
Go to Step 25 .
NO -
Repair an open in the wire between the No. 6 (7.5 A) fuse in the driver's under-dash fuse/relay box and relay circuit board.■
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect the 20P connector from the ACC unit.
  1. Check for continuity between the ACC unit 20P connector No. 16 terminal and body ground.
Is there continuity?
YES -
Repair a short to ground in the wire between the ACC unit and the relay circuit board.■
NO -
Go to Step 28 .
  1. Check for continuity between the ACC unit 20P connector No. 16 terminal and relay circuit board 10P connector No. 3 terminal.
Is there continuity?
YES -
Go to Step 29 .
NO -
Repair an open in the wire between the ACC unit and the relay circuit board.■
  1. Install the relay circuit board.
  1. Reconnect the ACC unit.
  1. Turn the ignition switch to ON (II).
  1. Turn the ignition switch to LOCK (0).
  1. Turn the ignition switch to ON (II) and the main switch to ON.
  1. Select the ADAPTIVE CRUISE CONTROL (ACC) from the DRIVING SUPPORT menu, then enter ACC RELAY from the FUNCTION TEST menu.
  1. Do the ACC relay function test.
  1. Check for DTCs with the HDS.
Is DTC 30 indicated?
YES -
Check for loose or poor connections. If the connections are OK, update the ACC unit, then recheck. If the ACC unit was already updated, replace the ACC unit. ■
NO -
Troubleshoot the indicated DTC(s). If there is no DTC, the system is OK at this time.■
Is DTC 30 indicated?
YES -
Go to Step 39 .
NO -
Go to Step 44 .
Is the relay circuit board OK?
YES -
Go to Step 40 .
NO -
Replace the under-hood fuse/relay box and recheck.■
  1. Disconnect the ACC unit 20P connector.
  1. Disconnect each brake light 4P connector and the high mount brake light 2P connector.
  1. Check for continuity between the ACC unit 20P connector No. 1 terminal and body ground.
Is there continuity?
YES -
Repair a short to ground in the wire between the ACC unit and the relay circuit board.■
NO -
Go to Step 43 .
  1. Check for continuity between the ACC unit 20P connector No. 1 terminal and relay circuit board 10P connector No. 8 terminal.
Is there continuity?
YES -
Check for loose or poor connections. If the connections are OK, update the ACC unit, then recheck. If the ACC unit was already updated, replace the ACC unit. ■
NO -
Repair an open in the wire between the ACC unit and the relay circuit board.■
  1. Check the brake lights with the brake pedal pressed.
Do the brake lights come on?
YES -
Intermittent failure. The system is OK at this time. Check for loose or poor connections.■
NO -