Automatic Air Conditioning

DTC B1061: Mode Selection Damper Control Motor and Potentiometer (Potentiometer system shorted to its power supply)














FUNCTION

Read the position of mode selection damper from the drive motor.

DETECTION LOGIC

This code is set when the mode selection damper control motor and potentiometer do not send any signal due to a short to power supply of the mode selection damper control motor and potentiometer circuit.

PROBABLE CAUSES

- Malfunction of connector.
- Malfunction of the harness (mode selection damper control motor and potentiometer circuit is open.)
- Malfunction of the mode selection damper control motor and potentiometer.
- Malfunction of the A/C-ECU.

DIAGNOSIS

Required Special Tool:

- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, check data list.





(1)
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.

Connect scan tool MB991958 to the data link connector.
(2)Start the engine.
(3)Set scan tool MB991958 to the data reading mode.

- Item 55: Air outlet c/o potentiometer
- Item 56: Air outlet c/o potentiometer (Target)

NOTE:
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 Go to Step 2.

NO Go to Step 3.

STEP 2. Recheck for diagnostic trouble code.

Recheck if the DTC is set.

(1)Erase the DTC.

(2)Turn the ignition switch to "OFF" position.

(3)Turn the ignition switch to "ON" position.

(4)Drive the vehicle and check if the diagnostic trouble code is set.

Q. Is the check result satisfactory?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.
NO Replace the A/C-ECU.
STEP 3. Check A/C-ECU connector C-15 and mode selection damper control motor and potentiometer connector C-104 for loose, corroded or damaged terminals, or terminals pushed back in the connector.









Q. Are A/C-ECU connector C-15 and mode selection damper control motor and potentiometer connector C-104 in good condition?

YES Go to Step 4.

NO Repair or replace the connector. Harness Connector Inspection.

STEP 4. Check the wiring harness for open circuit.









(1)Disconnect A/C-ECU connector C-15 and mode selection damper control motor and potentiometer connector C-104, and measure the resistance at the wiring harness side.





(2)Measure the resistance between A/C-ECU connector C-15 terminal 20 and mode selection damper control motor and potentiometer connector C-104 terminal 7.
OK: Less than 2 ohms

Q. Is the check result normal?

YES Go to Step 6.

NO Go to Step 5.

STEP 5. Check the wiring harness between A/C-ECU connector C-15 (terminal 20) and mode selection damper control motor and potentiometer connector C-104 (terminal 7).









NOTE:
Also check joint connector C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-01 is damaged, repair or replace the connector as described in Harness Connector Inspection Harness Connector Inspection.

Q. Is the wiring harness between A/C-ECU connector C-15 (terminal 20) and mode selection damper control motor and potentiometer connector C-104 (terminal 7) in good condition?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.

NO Repair the wiring harness.

STEP 6. Measure the voltage at A/C-ECU connector C-20.





(1)Disconnect A/C-ECU connector C-20, and measure the voltage at the wiring harness side.
(2)Turn the ignition switch to the "ON" position.
(3)Move the mode selection damper control motor to the DEF position.





(4)Measure the voltage between terminal 21 and ground.
OK: 0.4 - 0.8 volt

Q. Is the check result satisfactory?

YES Go to Step 8.

NO Go to Step 7.

STEP 7. Check the wiring harness between A/C-ECU connector C-20 (terminal 21) and mode selection damper control motor and potentiometer connector C-104 (terminal 3).









Q. Is the wiring harness between A/C-ECU connector C-20 (terminal 21) and mode selection damper control motor and potentiometer connector C-104 (terminal 3) in good condition?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.

NO Repair the wiring harness.

STEP 8. Check the mode selection damper control motor.

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





Check the mode selection damper control motor by the following procedures.





Q. Is the mode selection damper control motor in good condition?

YES Go to Step 9.

NO Replace the mode selection damper control motor and potentiometer.

STEP 9. Recheck for diagnostic trouble code.

Recheck if the DTC is set.

(1)Erase the DTC.

(2)Turn the ignition switch to "OFF" position.

(3)Turn the ignition switch to "ON" position.

(4)Drive the vehicle and check if the diagnostic trouble code is set.

Q. Is the check result satisfactory?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.
NO Replace the A/C-ECU.