Code No.U15A5
FCM/LDW/AHB CAN timeout
caution |
- If diagnosis
code No. U15A5 is set in the ETACS-ECU, always diagnose the CAN bus line.
- Before replacing the ECU, ensure that the power supply circuit, the earth circuit
and the communication circuit are normal.
- When the ETACS-ECU of vehicles without KOS is replaced, the encrypted code of the ignition
key needs to be registered to the ETACS-ECU. (If the encrypted code is not registered, the engine
cannot be started. Register the encrypted code as described in Immobilizer System - How
to Register Key ID.)
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DIAGNOSTIC FUNCTION
If the signal from FCM/LDW/AHB-ECU cannot be received, the ETACS-ECU sets diagnosis code
No. U15A5.
JUDGEMENT CRITERIA
After the following statuses continue to be true for 5 seconds, if the communication with
the FCM/LDW/AHB-ECU cannot be established for 2,500 ms or more, the ETACS-ECU determines that
a problem has occurred.
- No abnormality is present to the network.
- Ignition switch is in the ON position.
- No abnormality is present to the power supply fuse (IOD fuse), or the odometer value
is at 80.5 km or more.
- ETACS-ECU system voltage is at 10-16 V.
PROBABLE CAUSES
- Malfunction of FCM/LDW/AHB-ECU
- Malfunction of the ETACS-ECU
- Malfunction of the CAN bus
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.
Q.
Is the check result normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting).
STEP 2. M.U.T.-III other system diagnosis code
Check if diagnosis code is set in the FCM/LDW/AHB-ECU.
Q.
Is the diagnosis code set?
Troubleshoot the FCM/LDW/AHB. Refer to
.
Go to Step 3.
STEP 3. Check whether the diagnosis code is set again.
Check again if the diagnosis code is set in the ETACS-ECU.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
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(3)Check if diagnosis code is set.
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Q.
Is the diagnosis code set?
Replace the FCM/LDW/AHB-ECU, and then go to Step 4.
The trouble can be an intermittent malfunction such as a poor connection or open
circuit in the CAN bus lines between the FCM/LDW/AHB-ECU and the ETACS-ECU (GROUP 00 - How
to use Troubleshooting/inspection Service Points - How to Cope with Intermittent
Malfunction).
STEP 4. Check whether the diagnosis code is set again.
Check again if the diagnosis code is set in the ETACS-ECU.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
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(3)Check if diagnosis code is set.
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Q.
Is the diagnosis code set?
Replace the ETACS-ECU, and then Return to Step 1.
The trouble can be an intermittent malfunction such as a poor connection or open
circuit in the CAN bus lines between the FCM/LDW/AHB-ECU and the ETACS-ECU (GROUP 00 - How
to use Troubleshooting/inspection Service Points - How to Cope with Intermittent
Malfunction).