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DTC U0164: A/C-ECU CAN timeout
 
 
caution
  • If DTC U0164 is set, be sure to diagnose the CAN bus line.
  • 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 KOS-ECU stores DTC U0164.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of CAN bus line
  • Malfunction of A/C-ECU
  • Malfunction of KOS-ECU
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-III), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect scan tool (M.U.T.-III) ."
(2) Turn the power supply mode of the engine switch to ON.
(3) Diagnose the CAN bus line.
(4) Turn the power supply mode of the engine switch to OFF.
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 (M.U.T.-III), read the other system diagnostic trouble code.
Check again if the DTC is set in the A/C-ECU.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect scan tool (M.U.T.-III) ."
(2) Erase the DTC.
(3) Turn the power supply mode of the engine switch to ON.
(4) Check if DTC is set.
(5) Turn the power supply mode of the engine switch to OFF.
Is the DTC set?
Perform troubleshooting for the A/C-ECU (Refer to GROUP 55, Auto A/C Diagnosis ). On completion, go to Step 3.
Go to Step 3.
 
STEP 3. Using scan tool (M.U.T.-III), read the other system diagnostic trouble code.
Check if DTC U0164 is set in the combination meter.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect scan tool (M.U.T.-III) ."
(2) Erase the DTC.
(3) Turn the power supply mode of the engine switch to ON.
(4) Check if DTC is set.
(5) Turn the power supply mode of the engine switch to OFF.
Is the DTC set?
Go to Step 4.
Go to Step 5.
 
STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set in the KOS-ECU.
(1) Erase the DTC.
(2) Turn the power supply mode of the engine switch from OFF to ON.
(3) Check if DTC is set.
(4) Turn the power supply mode of the engine switch from ON to OFF.
Is the DTC set?
Replace the A/C-ECU.
A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the A/C-ECU and the KOS-ECU (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
 
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set in the KOS-ECU.
(1) Erase the DTC.
(2) Turn the power supply mode of the engine switch from OFF to ON.
(3) Check if DTC is set.
(4) Turn the power supply mode of the engine switch from ON to OFF.
Is the DTC set?
Replace KOS-ECU and register the ID codes (Refer to ).
A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the A/C-ECU and the KOS-ECU (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).