AIR CONDITIONING SYSTEM, Diagnostic DTC:B148B

DTC Code DTC Name
B148B Air Outlet Rear FOOT Damper Control Servo Motor Circuit (Passenger Side)

DESCRIPTION


The No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear RH))*1 or No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear LH))*2 sends pulse signals to inform the air conditioning amplifier assembly of the damper position. The air conditioning amplifier assembly activates the motor (normal or reverse) based on these signals to move the No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear RH))*1 or No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear LH))*2 to the appropriate position, which controls the air outlet switching.

The air conditioning amplifier assembly communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness assembly.

DTC No. Detection Item DTC Detection Condition Trouble Area Memory
B148B Air Outlet Rear FOOT Damper Control Servo Motor Circuit (Passenger Side)

  • Diagnosis condition: During No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear RH))*1 or No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear LH))*2 operation

  • Malfunction status: The damper servo operation request signal is output but the position information of the servo does not change or servo is malfunctioning

  • Detection time: Continuously for 30 seconds or more

  • No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear RH))*1

  • No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear LH))*2

  • Air conditioning harness assembly

  • Air conditioning amplifier assembly

 Memorized
DTC Diagnosis Condition Combination Table
Vehicle Condition
Pattern 1 Pattern 2
Diagnosis Condition During No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear RH))*1 or No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear LH))*2 operation ○ ○
Malfunction Status The damper servo operation request signal is output but the position information of the servo does not change ○ -
The damper servo operation request signal is output but the position information of the servo is malfunctioning - ○
Detection Time Continuously for 30 seconds or more Continuously for 30 seconds or more
Trip Count 1 trip 1 trip

Tech Tips

If the conditions match either of these patterns, a DTC will be output.

WIRING DIAGRAM

Figure 1. for LHD:

B004UMQE61

Figure 2. for RHD:

B004UMQE72

CAUTION / NOTICE / HINT

Note


  • Confirm that no mechanical problem is present because this diagnostic code can be output when either a damper link or the damper is mechanically locked.

  • When installing the damper servo motor, make sure to install it correctly.

  • When the servo motor is replaced, be sure to perform servo motor initialization.

    Click here

Tech Tips

Confirm that no mechanical problem is present because this DTC can be output when either a damper link or damper is mechanically locked.

PROCEDURE


  1. CHECK FOR DTC


    1. Check for DTCs.

      Click here


      Body Electrical > Air Conditioner > Trouble Codes
      Result
      Result Proceed to
      DTC B148B is output A
      DTC B148B Bnd B1497 Bre output. B

    B

    GO TO DTC B1497 Click here

    A

  2. CHECK NO. 5 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY


    1. Check for No. 5 air conditioning radiator damper servo sub-assembly is installed correctly.

      OK
      No. 1 air conditioning radiator damper servo sub-assembly is installed correctly.
      Result
      Proceed to
      OK
      NG

    NG

    REINSTALL NO. 5 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

    OK

  3. CHECK NO. 5 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (MOTOR, LINK, DAMPER)


    1. Check for a wire harness caught between the links of the motors and dampers.

      OK
      No wire harnesses are caught between the links of the motors and dampers.
      Result
      Proceed to
      OK
      NG

    NG

    REMOVE PINCHED WIRE HARNESS

    OK

  4. CHECK AIR CONDITIONING RADIATOR ASSEMBLY (DAMPER)


    1. Remove the No. 5 air conditioning radiator damper servo sub-assembly.

      Click here

    2. Operate the dampers by hand.

      OK
      The dampers are easily operated by hand.
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE AIR CONDITIONING RADIATOR ASSEMBLY

    OK

  5. PERFORM ACTIVE TEST USING GTS (AIR OUTELET REAR FOOT (DRIVER SIDE))


    • *1: for LHD

    • *2: for RHD

    • *3: Actually operates the No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear RH))*1 or No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear LH))*2.


    1. Remove the No. 5 air conditioning radiator damper servo sub-assembly.

      Click here

    2. Connect the No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear RH))*1 or No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear LH))*2 connector to No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear LH)).

    3. Connect the GTS to the DLC3.

    4. Turn the power switch on (IG).

    5. Turn the GTS on.

    6. Enter the following menus: Body Electrical / Air Conditioner / Active Test.

    7. Check the operation by referring to the table below.


      Body Electrical > Air Conditioner > Active Test
      Tester Display Measurement Item Control Range Restrict Condition
      Air Outlet Rear FOOT (Driver Side)

        for LHD:

      • No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear LH)) operation*3


        for RHD:

      • No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear RH)) operation*3

      Min.: 128

      Max.: 383

        for LHD:

      • Operates between 253 and 267 pulses


        for RHD:

      • Operates between 245 and 259 pulses

      Body Electrical > Air Conditioner > Active Test
      Tester Display
      Air Outlet Rear FOOT (Driver Side)
      OK
      No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear RH))*1 or No. 5 air conditioning radiator damper servo sub-assembly (MODE FOOT (rear LH))*2 is operated.
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY Click here

    NG

  6. CHECK NO. 5 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY


    1. Interchange the MODE FOOT (rear RH) servo motor with MODE FOOT (rear LH) servo motor and connect the connectors to them.

      Click here

    2. Clear the DTCs.

      Click here

    3. Check for DTCs.

      Click here

      Result
      Result Proceed to
      DTC B148A is output A
      DTC B148B is output B
      DTCs are not output C

      Tech Tips

      Codes other than DTC B148A and B148B may be output at this time, but they are not related to this check.


    A

    REPLACE NO. 5 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

    B

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    C

    USE SIMULATION METHOD TO CHECK Click here