B1045

DTC B1045: Air Mixing Damper Control Motor And Potentiometer (activating System Failure)

Air Mixing Control Motor Circuit:

DTC SET CONDITION
- If the air mixing damper control motor does not work normally, DTC No.B1045 will be set.

TECHNICAL DESCRIPTION (COMMENT)

Current trouble
- The A/C-ECU, the air mixing damper control motor and potentiometer, or connector(s) or wiring between the two may be defective.

Past trouble
- If DTC B1045 is stored as a past trouble, carry out diagnosis with particular emphasis on wiring and connector(s) between the A/C-ECU and the air mixing damper control motor and potentiometer. If the connectors and wiring are normal, and obviously the ECU is the cause of the trouble, replace the ECU. If in doubt, do not replace the ECU.

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 (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, diagnose the CAN bus line.

Use scan tool MB991958 to diagnose the CAN bus lines.







1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Diagnose the CAN bus line.

Q: Is the check result satisfactory?

YES : Go to Step 2.

NO : Repair the CAN bus lines. Then go to Step 7.

STEP 2. Recheck for diagnostic trouble code.

Recheck if the DTC is set.

1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.

Q: Is the check result satisfactory?

YES : It can be assumed that this malfunction is intermittent.

NO : Go to Step 3.

STEP 3. 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 10: air mix damper motor (MAX COOL position)
Item 11: air mix damper motor (middle position)
Item 12: 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 7.

NO : Go to Step 4.

STEP 4. Check A/C-ECU connector C-15 and air mixing damper control motor and potentiometer connector C-105 for loose, corroded or damaged terminals, or terminals pushed back in the connector.







Q: Are A/C-ECU connector C-15 and air mixing damper control motor and potentiometer connector C-105 in good condition?

YES : Go to Step 5.

NO : Repair or replace the connector. Then go to Step 7.

STEP 5. Check the wiring harness between A/C-ECU connector C-15 (terminals 1 and 2) and air mixing damper control motor and potentiometer connector C-105 (terminals 1 and 2).







- Check the A/C-ECU signal line for open and short circuit.

Q: Are the wiring harness between A/C-ECU connector C-15 (terminals 1 and 2) and air mixing damper control motor and potentiometer connector C-105 (terminals 1 and 2) in good condition?

YES : Go to Step 6.

NO : Repair the wiring harness. Then go to Step 7.

STEP 6. 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 following procedures.







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

YES : Repair the A/C-ECU. Then go to Step 7.

NO : Replace the air mixing damper control motor and potentiometer. Then go to Step 7.

STEP 7. 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.