DTC 32

DTC 32: Mode Selection Damper Control Motor and Potentiometer system

Mode Selection Damper Control Motor Potentiometer Circuit Part 1:

Mode Selection Damper Control Motor Potentiometer Circuit Part 2:

DTC SET CONDITION
- DTC 32 is set if there is an open or short circuit in the potentiometer input circuit, or if there is an open in the power circuit or ground circuit.

TROUBLESHOOTING HINT
- Malfunction of connector.
- Malfunction of the harness.
- Malfunction of the mode selection 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 data list.

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. Set scan tool MB991958 to the data reading mode.
Item 32: Air outlet c/o potentiometer.
- Check that the set position of the heater control matches the displayed position on the scan tool.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the sensor within the specified range?

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

NO: Go to Step 2.




STEP 2. Check A/C-ECU connector C-25 and mode selection damper control motor and potentiometer connector C-28 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are A/C-ECU connectors C-25 and mode selection damper control motor and potentiometer connector C-28 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-25 (terminals 10, 6 and 20) and mode selection damper control motor and potentiometer connector C-28 (terminals 2, 5 and 6).

NOTE: Also check intermediate connector C-30 and heater water temperature sensor connector C-29 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-30 and heater water temperature sensor connector C-29 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Are the wiring harnesses between A/C-ECU connectors C-25 (terminals 10, 6 and 20) and mode selection damper control motor and potentiometer connector C-28 (terminals 2, 5 and 6) in good condition?

YES: Go to Step 4.

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

STEP 4. Check the mode selection damper control motor and potentiometer.

MODE SELECTION DAMPER CONTROL MOTOR CHECK

CAUTION: Do not apply battery voltage when the damper is in the FACE or DEF position.







Operate the mode selection damper control motor as described in the table.

POTENTIOMETER CHECK
Measure the resistances between connector terminals 2 and 5, and between 5 and 6, while the mode selection damper control motor is running. The resistances should change gradually within the standard value.

Standard value: 0.65 (DEF)- 5.35 (FACE) kohms

Q: Are the mode selection damper control motor and potentiometer in good condition?

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

NO: Replace the mode selection 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.