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INSPECTION PROCEDURE 6: A/C outlet air temperature cannot be set
 
 
 
 
TECHNICAL DESCRIPTION (COMMENT)
If the air conditioning outlet temperature cannot be adjusted, the air mixing damper control motor or the heater controller assembly (A/C-ECU) may be faulty.
noteIt cannot be adjusted while the engine coolant temperature is low.
 
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the air mix damper control motor
  • Malfunction of the A/C compressor assembly
  • Malfunction of the heater controller assembly (A/C-ECU)
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Using scan tool (M.U.T.-IIISE), check whether the heater controller assembly (A/C-ECU) DTC is set.
Check that the DTC related to the air conditioning is not set (Refer to <heater controller assembly (A/C-ECU)>).
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the OFF position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ".
(2) Turn the electric motor switch from OFF position to ON position.
(3) Check the DTC is set.
(4) Turn the electric motor switch to the OFF position.
Is the DTC set?
Carry out the diagnostic trouble code procedures.
Go to Step 2.
 
STEP 2. Using scan tool (M.U.T.-IIISE), check actuator test [The heater controller assembly (A/C-ECU)].
Carry out the actuator test (Refer to ).
Item No.16: Dr air mix damper motor
Is the check result normal?
Go to Step 4.
Go to Step 3.
 
STEP 3. Check of open circuit in IG1, DA, DA', DB, DB' line between air mixing damper control motor connector (driver's side) and heater controller assembly (A/C-ECU) connector.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions ).
Repair the connector(s) or wiring harness.
 
STEP 4. The heater controller assembly (A/C-ECU) using scan tool (M.U.T.-IIISE), check actuator test.
Carry out the actuator test (Refer to ).
Item No.17: As air mix damper motor
Is the check result normal?
Go to Step 6.
Go to Step 5.
 
STEP 5. Check of open circuit in IG1, PA, PA', PB, PB' line between air mixing damper control motor connector (passenger's side) and heater controller assembly (A/C-ECU) connector.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions ).
Repair the connector(s) or wiring harness.
 
STEP 6. Replace the air mixing damper control motor (Refer to ), and recheck the trouble symptom.
Check that A/C outlet air temperature can be adjusted.
noteWhenever the motor is replaced, initialize the motor position by using the actuator test.
Is the check result normal?
This diagnosis is complete.
Replace the heater controller assembly (A/C-ECU) (Refer to ).