Code No. U15A0: Laser Radar (FCM-ECU) Time-out <Vehicle with FCM-LS>

caution

If diagnosis code U15A0 is set in the engine-ECU, surely perform CAN bus line diagnosis.
Replace ECU after certainly confirming that the communication circuits are normal.

TROUBLE JUDGEMENT

Check Condition

After 2 seconds have passed since the ignition switch was turned to "ON" position or the engine was started.
Battery positive voltage is more than 10 V and is less than 16 V.

Judgement Criterion

Unable to receive signals from the laser radar (FCM-ECU) through the CAN bus line for 4 seconds.

COMMENTS ON TROUBLE SYMPTOM

Current malfunction

Any wiring harness wire(s) and connector in CAN bus line between the engine-ECU and the laser radar (FCM-ECU), the power supply to the ECU(s) or the ECU(s) itself may be defective.

Past malfunction

Proceed with troubleshooting, focusing on the harness wires and connector in CAN bus line between engine-ECU and laser radar (FCM-ECU) and the power supply to the ECUs. For diagnosis procedure, refer to how to cope with past malfunctions. (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Treat Past Trouble

note

In the case of past malfunctions, M.U.T.-III CAN bus line diagnosis cannot detect a malfunction even if there is a malfunction in CAN bus. Therefore, check CAN bus line as in the case of response to intermittent malfunctions (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions

). It is possible to narrow down areas with a high possibility of malfunctions from diagnosis codes set in each ECU that performs CAN communication (Refer to GROUP 54C - Explanation about the M.U.T.-III CAN Bus Diagnostics

FAIL-SAFE AND BACKUP FUNCTION

The RMS (Foward) and FCM-LS are prohibited.

PROBABLE CAUSES

Failed harness and connector
Laser radar (FCM-ECU) fails
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis

Use M.U.T.-III to perform CAN bus line diagnosis.

Q. Is the check result normal?

	Go to Step 2.

	Repair CAN bus line (Refer to GROUP 54C - Troubleshooting - CAN Bus Diagnostics Table ). After repairing CAN bus line, go to Step 5 .

STEP 2. M.U.T.-III other system diagnosis code

Check whether another ECU, which communicates with the laser radar (FCM-ECU), has set diagnosis code No. U15A0 [Refer to GROUP 54C - CAN Communication-related Diagnosis Code (U-code) Table

Q. Is diagnosis code set?

	Go to Step 3.

	Go to Step 4.

STEP 3. M.U.T.-III diagnosis code

Confirm again whether the diagnosis code is set in the engine-ECU.

Erase the set diagnosis code.
Ignition switch: LOCK (OFF) → ON
Confirm whether the diagnosis code is set.

Q. Is diagnosis code set?

	Replace the laser radar (FCM-ECU), and then go to Step 5.

	Intermittent malfunction in CAN bus line between engine-ECU and the laser radar (FCM-ECU) (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 4. M.U.T.-III diagnosis code

Confirm again whether the diagnosis code is set in the engine-ECU.

Erase the set diagnosis code.
Ignition switch: LOCK (OFF) → ON
Confirm whether the diagnosis code is set.

Q. Is diagnosis code set?

	After replacing the engine-ECU, go to Step 5.

	Intermittent malfunction in CAN bus line between engine-ECU and the laser radar (FCM-ECU) (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 5. M.U.T.-III diagnosis code

Confirm again whether the diagnosis code is set in the engine-ECU.

Erase the set diagnosis code.
Ignition switch: LOCK (OFF) → ON
Confirm whether the diagnosis code is set.

Q. Is diagnosis code set?

	Go to Step 1.

	Check end.