DTC 41

DTC 41: Air Mixing Damper Control Motor and Potentiometer activating system

Air Mixing Damper Control Motor Circuit Part 1:

Air Mixing Damper Control Motor Circuit Part 2:

DTC SET CONDITION
- If the air mixing damper control motor does not work normally, DTC 41 will be set.

TROUBLESHOOTING HINT
- Malfunction of connector.
- Malfunction of the harness.
- Malfunction of the air mixing damper control motor and potentiometer.
- Malfunction of the A/C-ECU.

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A (Vehicles with CAN communication system)

STEP 1. Using scan tool MB991958, check actuator test.

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 to the data link connector.
2. Start the engine.
3. Use scan tool MB991958 to run the actuator test.
Item 05: air mix damper motor (MAX COOL position) Item 06: air mix damper motor (middle position) Item 07: air mix damper motor (MAX HOT position)
- Check that the air mixing damper control motor operates.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Does the motor operate normally?

YES: Replace the A/C-ECU. Then go to Step 5.

NO: Go to Step 2.




STEP 2. Check A/C-ECU connectors C-26 and air mixing damper control motor and potentiometer connector C-27 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are A/C-ECU connectors C-26 and air mixing damper control motor and potentiometer connector C-27 in good condition?

YES: Go to Step 3.

NO: Repair or replace the connector. Then go to Step 5.







STEP 3. Check the wiring harness between A/C-ECU connectors C-26 (terminal 22 and 25) and air mixing damper control motor and potentiometer connector C-27 (terminals 3 and 1).

NOTE: Also check intermediate connector C-30 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-30 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Are the wiring harness between A/C-ECU connectors C-26 (terminal 22 and 25) and air mixing damper control motor and potentiometer connector C-27 (terminals 3 and 1) in good condition?

YES: Go to Step 4.

NO: Repair the wiring harness. Then go to Step 5.

STEP 4. Check the air mixing damper control motor and potentiometer.

CAUTION: Do not apply battery voltage when the damper is in the MAX COOL or MAX HOT position.







Check the air mix damper control motor by the procedures.

Q: Are the air mixing damper control motor and potentiometer in good condition?

YES: Replace the A/C-ECU. Then go to Step 5.

NO: Replace the air mixing damper control motor and potentiometer. Then go to Step 5.

STEP 5. Recheck for diagnostic trouble code.

Check again if the DTC is set.




1. Connect scan tool MB991958 to the data link connector
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the check result satisfactory?

YES: The procedure is complete.

NO: Return to Step 1.