DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
READ VALUE USING INTELLIGENT TESTER (REAR AIR MIX DAMPER SERVO MOTOR)
CHECK HARNESS AND CONNECTOR (NO. 2 AIR CONDITIONING HARNESS - AIR CONDITIONING AMPLIFIER)
CHECK REAR AIR MIX DAMPER SERVO MOTOR
CHECK NO. 2 AIR CONDITIONING HARNESS ASSEMBLY
DTC B1488/88 Rear Air Mix Damper Control Servo Motor Circuit on Front Passenger Side
DESCRIPTION
The rear air mix damper servo motor RH*1 or LH*2 sends pulse signals to indicate the damper position to the air conditioning amplifier assembly. The air conditioning amplifier assembly activates the motor (normal or reverse) based on these signals to move the rear air mix damper to the appropriate position. This adjusts the amount of air passing through the heater core after passing the evaporator and controls the temperature of the blown air.
- Confirm that no mechanical problem is present because this trouble code can be output when either a damper link or damper is mechanically locked.
| DTC Code | DTC Detection Condition | Trouble Area |
| B1488/88 |
The rear air mix damper position does not change even if the air conditioning amplifier assembly operates the air mix damper servo motor. |
Rear air mix damper servo motor RH*1
Rear air mix damper servo motor LH*2
No. 2 air conditioning harness assembly
Harness or connector
Air conditioning amplifier assembly
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WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.READ VALUE USING INTELLIGENT TESTER (REAR AIR MIX DAMPER SERVO MOTOR) |
Use the Data List to check if the servo motor is functioning properly.
Air Conditioner| Tester Display | Measurement Item/Range | Normal Condition | Diagnostic Note |
| A/M Servo Targ Pulse (Rear P) |
Rear air mix damper servo motor (for front passenger side) target pulse /
Min.: 8, Max.: 53 (for LHD)
Min.: 9, Max.: 54 (for RHD) |
for LHD
MAX COOL: 53 (pulse)
MAX HOT: 8 (pulse)
for RHD
MAX COOL: 9 (pulse)
MAX HOT: 54 (pulse)
| - |
- OK:
- The display is as specified in the normal condition.
Result| Result | Proceed to |
| OK (Checking from the DTC) | A |
| OK (Checking from the PROBLEM SYMPTOMS TABLE) | B |
| NG | C |
| | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE ()
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| | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY ()
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| 2.CHECK HARNESS AND CONNECTOR (NO. 2 AIR CONDITIONING HARNESS - AIR CONDITIONING AMPLIFIER) |
Disconnect the K19 No. 2 air conditioning harness connector.
Disconnect the E36 amplifier connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| K19-2 (RBUG) - E36-12 (RBUG) | Always | Below 1 Ω |
| K19-3 (RBUS) - E36-13 (RBUS) |
| K19-4 (RBBU) - E36-14 (RBBU) |
| E36-12 (RBUG) - Body ground | Always | 10 kΩ or higher |
| E36-13 (RBUS) - Body ground |
| E36-14 (RBBU) - Body ground |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 3.CHECK REAR AIR MIX DAMPER SERVO MOTOR |
Replace the rear air mix damper servo motor ().
- Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a normal one.
Check for DTCs ().
Result| Result | Proceed to |
| DTC B1488/88 is not output | A |
| DTC B1488/88 is output | B |
| A | |
| |
| END (REAR AIR MIX DAMPER SERVO MOTOR IS DEFECTIVE) |
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| 4.CHECK NO. 2 AIR CONDITIONING HARNESS ASSEMBLY |
Replace the No. 2 air conditioning harness assembly ().
Check for DTCs ().
Result| Result | Proceed to |
| DTC B1488/88 is not output | A |
| DTC B1488/88 is output | B |
| | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY ()
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| A | |
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| END (NO. 2 AIR CONDITIONING HARNESS ASSEMBLY IS DEFECTIVE) |
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