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DTC U0164: A/C-ECU CAN Timeout
 
 
caution
  • If the DTC U0164 is set in the occupant classification-ECU, always diagnose the CAN main bus lines.
  • When replacing the ECU, always check that the communication circuit is normal.
 
 
DIAGNOSTIC FUNCTION
If the signal from A/C-ECU cannot be received, the occupant classification-ECU sets the DTC U0164.
 
 
JUDGMENT CRITERIA
Because of the CAN-B bus circuit malfunction, if the occupant classification-ECU becomes unable to perform the normal data transmission, the occupant classification-ECU determines that an abnormality is present.
 
 
TROUBLESHOOTING HINTS
  • The CAN bus line may be defective
  • The A/C-ECU may be defective
  • The occupant classification-ECU may be defective
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
(1)
cautionTo 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.
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 diagnostic trouble code.
Check if DTC is set to the A/C-ECU.
Is the DTC set?
Diagnose the A/C. Then go to Step 4.
Go to Step 3.
 
STEP 3. Using scan tool MB991958, read diagnostic trouble code No. U0164 for other system.
Check if the DTC U0164 is set in ETACS-ECU, SRS-ECU, combination meter, KOS-ECU or WCM, CAN box unit, radio and CD player, satellite radio tuner, OSS-ECU.
Is the DTC set?
Replace the A/C control panel (Refer to GROUP 55A, Heater Control Unit).
Go to Step 4.
 
STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set to the occupant classification-ECU.
(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.
Is the DTC set?
Replace the passenger seat cushion frame assembly (Refer to GROUP 52A, Front Seat Assembly ).
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).