Manufacturer Code Charts: 30
Adaptive Cruise Control (ACC) DTC Troubleshooting: 30
DTC 30:
Brake Light Relay Circuit Malfunction
1. Check the brake lights without pressing the brake pedal.
Are the brake lights off?
YES -
Go to step 10.
NO -
Go to step 2.
2. Check the brake pedal height, and adjust it if needed Adjustments.
3. 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.
4. Test the brake pedal position switch Testing and Inspection.
Is the brake pedal position switch OK?
YES -
Go to step 5.
NO -
Adjust or replace the brake pedal position switch, and recheck Service and Repair.�
5. Test the brake light relay Power Relay Test.
Is the relay OK?
YES -
Go to step 6.
NO -
Replace the relay, and recheck.�
6. Disconnect the brake pedal position switch 4P connector.
7. Measure the voltage between brake pedal position switch 4P connector terminal No. 2 and body ground.
Is there battery voltage?
YES -
Repair a short to power in the wire between the brake pedal position switch and the brake light relay.�
NO -
Go to step 8.
8. Disconnect the ACC unit 20P connector.
9. Measure the voltage between ACC unit 20P connector terminal No. 1 and body ground.
Is there battery voltage?
YES -
Repair a short to power in the wire between the ACC unit and the brake light relay, or between the ACC unit and the brake lights circuits.�
NO -
Check for loose or poor connections. If OK, update the ACC unit Programming and Relearning, then recheck. If the ACC unit was already updated, replace the ACC unit Service and Repair.�
10. Clear the DTCs with the HDS.
11. Press the MAIN switch ON.
12. Check the brake lights with the brake pedal pressed.
Do the brake lights come on?
YES -
Go to step 13.
NO -
Go to step 37.
13. Check for DTCs with the HDS.
Is DTC 30 indicated?
YES -
Go to step 14.
NO -
Go to step 21.
14. Turn the ignition switch to LOCK (0).
15. Remove the brake light relay.
16. Disconnect the ACC unit 20P connector.
17. Disconnect the VSA modulator-control unit 46P connector Service and Repair.
18. Disconnect both rear taillight connectors from the taillights and, if equipped, the trailer light harness connector from the rear fuse box.
19. Measure the resistance between ACC unit 20P connector terminal No. 1 and body ground. There should be an open circuit or at least 1 MOhms.
Is the resistance as specified?
YES -
Go to step 20.
NO -
Repair a short to ground in the wire between the ACC unit and the brake light relay, or between the ACC unit and the brake lights circuits.�
20. Measure the resistance between ACC unit 20P connector terminal No. 1 and brake light relay 5P connector terminal No. 1. There should be less than 1.0 Ohms.
Is the resistance as specified?
YES -
Check for loose or poor connections. If OK, update the ACC unit Programming and Relearning, then recheck. If the ACC unit was already updated, replace the ACC unit Service and Repair.�
NO -
Repair an open in the wire between the ACC unit and the brake light relay.�
21. Test the brake light relay Power Relay Test.
Is the relay OK?
YES -
Go to step 22.
NO -
Replace the relay, and recheck.�
22. Remove the brake light relay.
23. Measure the voltage between brake light relay 5P connector terminal No. 2 and body ground. There should be battery voltage.
Is there battery voltage?
YES -
Go to step 24.
NO -
Repair an open in the wire between the No. 11 (15 A) fuse in the main under-hood fuse box and the brake light relay.�
24. Turn the ignition switch to ON (II).
25. Measure the voltage between brake light relay 5P connector terminal No. 5 and body ground. There should be battery voltage.
Is there battery voltage?
YES -
Go to step 26.
NO -
Repair an open in the wire between the No. 21 (7.5 A) fuse in the under-dash fuse/relay box and the brake light relay.�
26. Turn the ignition switch to LOCK (0).
27. Disconnect the ACC unit 20P connector.
28. Measure the resistance between ACC unit 20P connector terminal No. 16 and body ground. There should be an open circuit or at least 1 MOhms.
Is the resistance as specified?
YES -
Go to step 29.
NO -
Repair a short to ground in the wire between the ACC unit and the brake light relay.�
29. Measure the resistance between ACC unit 20P connector terminal No. 16 and brake light relay 5P connector terminal No. 3. There should be less than 1.0 Ohms.
Is the resistance as specified?
YES -
Go to step 30.
NO -
Repair an open in the wire between the ACC unit and the brake light relay.�
30. Install the brake light relay.
31. Reconnect the ACC unit 20P connector.
32. Clear the DTCs with the HDS.
33. Turn the ignition switch to ON (II), then wait for 10 seconds, and press the MAIN switch ON.
34. Select ADAPTIVE CRUISE CONTROL (ACC) from the DRIVING SUPPORT menu, then enter ACC RELAY from the FUNCTION TEST menu.
35. Do the brake light relay function test with the HDS.
36. Check for DTCs with the HDS.
Is DTC 30 indicated?
YES -
Check for loose or poor connections. If OK, update the ACC unit Programming and Relearning, then recheck. If the ACC unit was already updated, replace the ACC unit Service and Repair.�
NO -
Troubleshoot the indicated DTC(s). If there are no DTCs, the system is OK at this time.�
37. Check for DTCs with the HDS.
Is DTC 30 indicated?
YES -
Go to step 38.
NO -
Go to step 44.
38. Test the brake light relay Power Relay Test.
Is the relay OK?
YES -
Go to step 39.
NO -
Replace the relay, and recheck.�
39. Remove the brake light relay.
40. Disconnect the ACC unit 20P connector.
41. Disconnect each taillight 3P connector and the high mount brake light 2P connector.
42. Measure the resistance between ACC unit 20P connector terminal No. 1 and body ground. There should be an open circuit or at least 1 MOhms.
Is the resistance as specified?
YES -
Go to step 43.
NO -
Repair a short to ground in the wire between the ACC unit and the brake light relay, or between the ACC unit and the brake lights circuits.�
43. Measure the resistance between ACC unit 20P connector terminal No. 1 and brake light relay 5P connector terminal No. 1. There should be less than 1.0 Ohms.
Is the resistance as specified?
YES -
Check for loose or poor connections. If OK, update the ACC unit Programming and Relearning, then recheck. If the ACC unit was already updated, replace the ACC unit Service and Repair.�
NO -
Repair an open in the wire between the ACC unit and the brake light relay.�
44. Check the brake pedal height, and adjust it if needed Adjustments.
45. Test the brake pedal position switch Testing and Inspection.
46. 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 -
Repair an open in the wire or poor ground (G701, G702).�