Code No. U1110: A/C-ECU Time-out

caution

If diagnosis code U1110 is output from engine-A/T-ECU, surely perform CAN busline diagnosis.

caution

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

TROUBLE JUDGMENT

Check Conditions

While the cranking switch is in OFF position, or when 3 seconds pass after the cranking switch is in OFF from ON.
The battery voltage is 10 V or more.

Judgment Criterion

The signals cannot be received from A/C-ECU through CAN busline.

COMMENT ON TROUBLE SYMPTOM

Current malfunction

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

Past malfunction

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

note

In case of Past malfunction, 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

).The diagnosis codes being output to each ECU with CAN communication can narrow down the most suspected area (Refer to GROUP 54F - Diagnosis - CAN Bus Diagnostics Chart

PROBABLE CAUSE

Failed harness and connector in CAN busline
Failed A/C-ECU
Failed engine-A/T-ECU

DIAGNOSIS

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

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 54F - Diagnosis - CAN Bus Diagnostics Chart ), and then go to Step 6 .

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

Confirm whether the diagnosis code is output from A/C-ECU.

Q. Is the diagnosis code set?

	Perform the troubleshooting of A/C-ECU (Refer to GROUP 54E Troubleshooting - Inspection Chart For Diagnosis Code ).

	Go to Step 3 .

STEP 3. M.U.T.-III other system diagnosis codes

Confirm whether Diagnosis Code U1110 A/C-ECU time-out is output from the following ECU having CAN communication with A/C-ECU.

ETACS-ECU

Q. Is the diagnosis code set?

	Go to Step 4 .

	Go to Step 5 .

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

Reconfirm whether the diagnosis code is output from engine-A/T-ECU.

Erase the diagnosis code being output.
Ignition switch: LOCK (OFF) to ON
Confirm whether the diagnosis code is output.

Q. Is the diagnosis code set?

	Replace A/C-ECU, then go to Step 6 .

	Intermittent malfunction in CAN busline between engine-A/T-ECU and A/C-ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).

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

Reconfirm whether the diagnosis code is output from engine-A/T-ECU.

Erase the diagnosis code being output.
Ignition switch: LOCK (OFF) to ON
Confirm whether the diagnosis code is output.

Q. Is the diagnosis code set?

	Replace engine-A/T-ECU, go to Step 6 .

	Intermittent malfunction in CAN busline between engine-A/T-ECU and A/C-ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).

STEP 6. M.U.T.-III diagnosis code

Reconfirm whether the diagnosis code is output from engine-A/T-ECU.

Erase the diagnosis code being output.
Ignition switch: LOCK (OFF) to ON
Confirm whether the diagnosis code is output.

Q. Is the diagnosis code set?

	Go to Step 1 .

	Check end.