Manufacturer Code Charts: 44
Adaptive Cruise Control (ACC) DTC Troubleshooting: 44
DTC 44:
Cal FL Brake Fluid Pressure Sensor Circuit Open/Short
1. Clear the DTCs with the HDS.
2. Turn the ignition switch to ON (II), then wait for 10 seconds.
3. Watch the ACC indicator.
Does the ACC indicator (amber) stay off?
YES -
Intermittent failure, the system is OK at this time. Check for loose or poor connections.
NO -
Go to step 4.
4. Check for DTCs with the HDS.
Is DTC 44 indicated?
YES -
Go to step 5.
NO -
Troubleshoot the indicated DTC(s).
5. Without the brake pedal pressed, check the left front brake fluid pressure voltage (LF BRAKE P) with the HDS.
Is there about 0.5 V?
YES -
Go to step 6.
NO -
Go to step 9.
6. Test the brake booster Testing and Inspection.
7. Start the engine, then press the brake pedal with about 314 N (32 kgf, 70.6 lbf) of pressure.
8. Check the left front brake fluid pressure voltage (LF BRAKE P) with the HDS.
Is there about 2.5 V?
YES -
Check for loose or poor connections. If OK, update the ACC unit Testing and Inspection, then recheck. If the ACC unit was already updated, replace the ACC unit Service and Repair.
NO -
Go to step 9.
9. Turn the ignition switch to LOCK (0).
10. Disconnect the ACC unit 20P connector.
11. Measure the resistance between ACC unit 20P connector terminal No. 5 and body ground. There should be an open circuit or at least 1 MOhms.
Is the resistance as specified?
YES -
Go to step 12.
NO -
Repair a short to ground in the wire between the ACC unit and the left front brake fluid pressure sensor.
12. Disconnect the left front brake fluid pressure sensor 3P connector.
13. Connect left front brake fluid pressure sensor 3P connector terminal No. 2 to body ground with a jumper wire.
14. Measure the resistance between ACC unit 20P connector terminal No. 5 and body ground. There should be less than 1.0 Ohms.
Is the resistance as specified?
YES -
Go to step 15.
NO -
Repair an open in the wire between the ACC unit and the left front brake fluid pressure sensor.
15. Remove the jumper wire from the left front brake fluid pressure sensor.
16. Reconnect all connectors.
17. Turn the ignition switch to ON (II).
18. Measure the voltage between ACC unit 20P connector terminals No. 3 and No. 5. There should be about 5 V.
Is there about 5V?
YES -
Go to step 19.
NO -
Check for loose or poor connections. If OK, update the ACC unit Testing and Inspection, then recheck. If the ACC unit was already updated, replace the ACC unit Service and Repair.
19. Turn the ignition switch to LOCK (0).
20. Disconnect the ACC unit 20P connector.
21. Measure the resistance between ACC unit 20P connector terminal No. 14 and body ground. There should be an open circuit or at least 1 MOhms.
Is the resistance as specified?
YES -
Go to step 22.
NO -
Repair a short to ground in the wire between the ACC unit and the left front brake fluid pressure sensor.
22. Disconnect the left front brake fluid pressure sensor 3P connector.
23. Connect left front brake fluid pressure sensor 3P connector terminal No. 3 to body ground with a jumper wire.
24. Measure the resistance between ACC unit 20P connector terminal No. 14 and body ground. There should be less than 1.0 Ohms.
Is the resistance as specified?
YES -
Go to step 25.
NO -
Repair an open in the wire between the ACC unit and the left front brake fluid pressure sensor.
25. Measure the resistance between ACC unit 20P connector terminals No. 5 and No.14. There should be an open circuit or at least 1 MOhms.
Is the resistance as specified?
YES -
Go to step 26.
NO -
Repair a short in the wire between the PRESS FL line and the VCC line.
26. Connect left front brake fluid pressure sensor 3P connector terminal No. 1 to body ground with a jumper wire.
27. Measure the resistance between ACC unit 20P connector terminal No. 3 and body ground. There should be less than 1.0 Ohms.
Is the resistance as specified?
YES -
Go to step 28.
NO -
Repair an open in the wire between the ACC unit and the left front brake fluid pressure sensor.
28. Remove the jumper wire from the left front brake fluid pressure sensor.
29. Reconnect all connectors.
30. Turn the ignition switch to ON (II).
31. Measure the voltage between ACC unit 20P connector terminals No. 3 and No. 14.There should be voltage between 0.4 - 0.6 V.
Is the voltage as specified?
YES -
Go to step 32.
NO -
Replace the left front brake fluid pressure sensor Service and Repair.
32. Clear the DTCs with the HDS.
33. Watch the ACC indicator.
Does the ACC indicator stay off?
YES -
Intermittent failure, the system is OK at this time. Check for loose or poor connections.
NO -
Go to step 34.
34. Check for DTCs with the HDS.
Is DTC 44 indicated?
YES -
Check for loose or poor connections. If OK, update the ACC unit Testing and Inspection, then recheck. If the ACC unit was already updated, replace the ACC unit Service and Repair.
NO -
Troubleshoot the indicated DTC(s).