Hands Free Cellular Phone System
DTC U0164: A/C CAN TimeoutCAUTION:
- If DTC U0164 is set, be sure to diagnose the CAN bus line.
- When replacing the module, always check that the communication circuit is normal.
TECHNICAL DESCRIPTION (COMMENT)
If the signal from A/C-ECU cannot be received, the hands free module sets the DTC U0164.
TROUBLESHOOTING HINTS
- The CAN bus line may be defective.
- The A/C-ECU may be defective.
- The hands free module may be defective.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicles 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.
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.
1. Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III)." 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?
YES : Go to Step 2.
NO : Repair the CAN bus line.
STEP 2. Using scan tool MB991958, read the A/C-ECU diagnostic trouble code.
Check if DTC is set to the A/C-ECU.
Q: Is the DTC set?
YES : Troubleshoot the A/C-ECU [vehicle with A/C] or heater control unit [vehicle without A/C] (Refer to Automatic A/C Diagnosis). Diagnostic Trouble Code Descriptions
NO : Go to Step 3.
STEP 3. Using scan tool MB991958, read the ETACS diagnostic trouble code.
Check if the DTC U0164 is set to the ETACS-ECU.
Q: Is the DTC set?
YES : Go to Step 4.
NO : Go to Step 5.
STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set to the hands free module
1. Erase the DTC.
2. Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
3. Check if DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES : Replace the A/C-ECU.
NO : 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 and the hands free module.
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set to the hands free module
1. Erase the DTC.
2. Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
3. Check if DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES : Replace the hands free module.
NO : 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 and the hands free module.