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

caution

If Diagnosis Code U1110 is output from Engine-ECU <M/T> or engine-A/T-ECU <A/T> 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 10V 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-ECU <M/T> or engine-A/T-ECU <A/T> and A/C-ECU or between engine-ECU <M/T> or engine-A/T-ECU <A/T> and A/C-ECU, by malfunction in the power supply system of A/C-ECU, in A/C-ECU itself, in engine-ECU <M/T> or engine-A/T-ECU <A/T>.

Past malfunction

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

) for the diagnosis procedure.

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

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

PROBABLE CAUSE

Failed harness and connector
Failed A/C-ECU
Failed engine-ECU <M/T>
Failed engine-A/T-ECU <A/T>

DIAGNOSIS

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 54F - Diagnosis - Can Bus Diagnostic Table ), and then go to Step 6 .

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

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

Q. Is the diagnosis code output?

	Perform the troubleshooting of A/C-ECU (Refer to GROUP 55 Troubleshooting - Diagnosis Code Chart ).

	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 output?

	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-ECU <M/T> or engine-A/T-ECU <A/T>.

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

Q. Is the diagnosis code output?

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

	Intermittent malfunction in CAN busline between engine-ECU <M/T> or engine-A/T-ECU <A/T> 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-ECU<M/T> or engine-A/T-ECU <A/T>.

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

Q. Is the diagnosis code output?

	Replace engine-ECU<M/T> or engine-A/T-ECU <A/T>, go to Step 6 .

	Intermittent malfunction in CAN busline between engine-ECU <M/T> or engine-A/T-ECU <A/T> 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-ECU <M/T> or engine-A/T-ECU <A/T>.

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

Q. Is the diagnosis code output?

	Go to Step 1 .

	Check end.