![[Previous]](../../../buttons/fprev.png)
![[Next]](../../../buttons/fnext.png)
DTC U0164: A/C/Heater control unit CAN timeout
| caution |
- If DTC U0164 is set to the ETACS-ECU, always diagnose the CAN bus line.
- Before replacing the ECU, ensure that the communication circuit is normal.
|
TROUBLE JUDGMENT
If the signal from A/C-ECU <vehicles with A/C> or heater control unit <vehicles without A/C> cannot be received, the ETACS-ECU sets DTC U0164.
JUDGMENT CRITERIA
After the following statuses continue to be true for 5 seconds, if the communication with the A/C-ECU <vehicles with A/C> or heater control unit <vehicles without A/C> cannot be established for 0.6 second 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 (50.0 miles) or more.
- ETACS-ECU system voltage is at 10-16 volts.
TROUBLESHOOTING HINTS
- The A/C-ECU <vehicles with A/C> or heater control unit <vehicles without A/C> may be defective.
- The ETACS-ECU may be defective.
- The CAN bus may be defective.
|
|
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
|
|
|
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
|
|
(1)
| caution |
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
|
Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III)  ."
(2)Turn the ignition switch to the "ON" position.
(3)Diagnose the CAN bus line.
(4)Turn the ignition switch to the "LOCK" (OFF) position.
Q.
Is the CAN bus line found to be normal?
 Go to Step 2.
 Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).
|
|
|
STEP 2. Using scan tool MB991958, read the A/C/Heater control unit diagnostic trouble code.
|
|
|
Check if DTC is set to the A/C/Heater control unit.
|
|
|
Troubleshoot the A/C/Heater control unit (Refer to GROUP 55A, Manual A/C Diagnosis or GROUP 55B, Auto A/C Diagnosis ).
|
|
|
|
|
|
Go to Step 3.
|
|
|
|
|
|
STEP 3. Using scan tool MB991958, read the combination meter diagnostic trouble code.
|
|
|
Check if the DTC U0164 is set to the combination meter.
|
|
|
Go to Step 4.
|
|
|
|
|
|
Go to Step 5.
|
|
|
|
|
|
STEP 4. Recheck for diagnostic trouble code.
|
|
|
Check again if the DTC is set to the ETACS-ECU.
|
|
|
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
|
|
|
(4)Turn the ignition switch to the "LOCK" (OFF) position.
|
|
|
Replace the A/C-ECU <vehicles with A/C> or heater control unit <vehicles without A/C>.
|
|
|
|
|
|
The trouble can be an intermittent malfunction such as a poor connection or open circuit in the CAN bus lines between the A/C-ECU <vehicles with A/C> or heater control unit <vehicles without A/C> and the ETACS-ECU (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
|
|
|
|
|
|
STEP 5. Recheck for diagnostic trouble code.
|
|
|
Check again if the DTC is set to the ETACS-ECU.
|
|
|
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
|
|
|
(4)Turn the ignition switch to the "LOCK" (OFF) position.
|
|
|
Replace the ETACS-ECU.
|
|
|
|
|
|
The trouble can be an intermittent malfunction such as a poor connection or open circuit in the CAN bus lines between the A/C-ECU <vehicles with A/C> or heater control unit <vehicles without A/C> and the ETACS-ECU (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
|
|
|
|
)