Code No. U15A0: FCM-ECU Time-out <Vehicles 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 Conditions

After 2 seconds since the ignition switch is turned "ON" or since the completion of engine start.
Battery positive voltage is more than 10 V and is less than 16.5 V.

Judgement Criterion

Unable to receive FCM-ECU signals through the CAN bus line for 4 seconds.

COMMENTS ON TROUBLE SYMPTOM

Current malfunction

The failure is possibly caused by malfunction of the harness and connector in CAN bus line between engine-ECU and FCM-ECU, by malfunction in the power supply system of FCM-ECU, in FCM-ECU itself, in engine-ECU.

Past malfunction

Proceed with troubleshooting focusing on malfunction of the harness and connector in CAN bus line between engine-ECU and FCM-ECU and malfunction in the power supply system of FCM-ECU. 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 to 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 and FCM-LS are prohibited.

PROBABLE CAUSES

Failed harness and connector
Failed FCM-ECU
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 Diagnosis Table ). After repairing CAN bus line, go to Step 5 .

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

Check that the other ECU performing CAN communication with FCM-ECU sets diagnosis code No. U15A0 (Refer to GROUP 54C - CAN-related Diagnosis 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?

	After replacing laser radar (FCM-ECU) (Refer to GROUP 54A - FCM-LS, Laser Radar ), go to Step 5.

	Intermittent malfunction in CAN bus line between engine-ECU and 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 engine-ECU, go to Step 5.

	Intermittent malfunction in CAN bus line between engine-ECU and 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.

	This diagnosis is complete.