Code No. U1102 ASTC-ECU Time-out

caution

If Diagnosis Code U1102 is set from engine-ECU surely perform CAN busline diagnosis.

caution

Replace ECU after certainly confirming that the communication circuits are normal.

TROUBLE JUDGMENT

Check Condition

The diagnosis code setting enabled signal is received from ETACS-ECU.

Judgment Criterion

The signals cannot be received from ASTC-ECU for 65 second or more.

COMMENT ON TROUBLE SYMPTOM

Current malfunction

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

Past malfunction

Focus on diagnosing malfunction of the harness and connector in CAN busline between engine-ECU and ASTC-ECU as well as malfunction in the power supply system of ASTC-ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions

note

In case of Past trouble, M.U.T.-III CAN bus diagnosis cannot detect the failure even if there is malfunction in CAN bus, so that check CAN busline in the same way as Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions

). The diagnosis codes being output to each ECU with CAN communication can narrow down the most suspected area. (Refer to GROUP 54D - Explanation About The M.U.T.-III Can Bus Diagnostics

PROBABLE CAUSES

Failed of the harness and the connector
Failed engine-ECU
Failed ASTC-ECU

DIAGNOSIS PROCEDURE

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

Using M.U.T.-III, perform CAN busline diagnosis.

Q. Is the check result normal?

	Go to Step 2.

	Correct CAN busline (Refer to GROUP 54D - Troubleshooting - Can Bus Diagnostics Table ), and then go to Step 4.

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

Confirm whether the diagnosis codes are output from ASTC-ECU.

Q. Is the diagnosis code output?

	Perform the troubleshooting of ASTC system (Refer to GROUP 35C - Troubleshooting - Diagnostic Trouble Code Chart ).

	Go to Step 3.

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

Reconfirm whether the diagnosis codes are output from engine-ECU

Erase the diagnosis codes being output.
Ignition switch: "LOCK" (OFF) to ON
Confirm whether the diagnosis codes are output.

Q. Is the diagnosis code output?

	Go to Step 4.

	Intermittent malfunction in CAN busline between engine-ECU and ASTC-ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).

STEP 4. Replace the ASTC-ECU

After replacing the ASTC-ECU, re-check the diagnosis code output.

Q. Is the diagnosis code output?

	Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

	The check is end.