B1209

B1209

Component Location:

General Description
Intake door located at heater unit controls the inlet of car. It contains intake motor that changes intake door position and potentiometer that monitors position of intake door. When driver operates the intake switch, ECU receives mode signal from intake switch and operates intake door motor to turn intake door to intended position. (with FRE mode signal, intake door is closed and with REC mode signal, intake door is opened) In operation, potentiometer delivers intake door position transformed into voltage value to A/C ECU.

DTC Description
The ECM sets DTC B1209 if there is a short to power in the Intake actuator signal harness General

DTC Detecting Condition:

Schematic Diagram:

Signal Waveform:

Monitor Scantool Data
1. Connect scantool to Data Link Connector (DLC).
2. Engine "ON".
3. Monitor the "Intake potentiometer" Parameter on the Scantool. While operating Intake switch






4. Are the DTC B1209 present and is parameter of "Intake potentiometer" fixed?
- Parameter of "Intake potentiometer" will be fixed at 100% (or any value above 90%), or 0% (or any value below 10%), if there is any fault in Intake actuator.

YES
a. Go to "Inspection & Repair" procedure.

No
a. Fault is intermittent caused by poor contact in the sensor's and/or A/C control unit's connector or was repaired and A/C control unit memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.

Terminal and Connector Inspection
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?

YES
a. Repair as necessary and go to "Verification Vehicle Repair" procedure.

No
a. Go to "W/Harness Inspection" procedure.

Signal Circuit Inspection
1. Check for short in harness
1. Ignition "OFF".
2. Disconnect Intake actuator.
3. Measure resistance between terminal "4" and "5" of Intake actuator.

Specification : Approx. Infinite ohms






4. Is the measured resistance within specifications?

YES
a. Go to "Ground circuit Inspection" procedure.

No
a. Check for short to power harness in signal harness. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

Ground Circuit inspection
1. Check for open in ground harness
1. Ignition "OFF".
2. Disconnect Intake actuator.
3. Measure resistance between terminal "3" of Intake actuator and chassis ground.

Specification : Approx. 0 ohm






4. Is the measured resistance within specifications?

YES
a. Go to "Component Inspection" procedure.

No
a. Check for open in ground harness. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

Component Inspection

Check intake actuator.
1. Check actuator motor
1. Ignition "OFF".
2. Disconnect intake actuator.
3. Connect (+) terminal of battery to terminal 2 of intake actuator and (-) terminal to terminal 1.






4. Dose the actuator work properly?

YES
a. Go to "Check potentiometer" procedure.

No
a. Substitute with a known-good actuator and check for proper operation. If the problem is corrected, replace actuator and then go to "Verification of Vehicle Repair" procedure.

2. Check actuator potentiometer
1. Ignition "ON".
2. Connect intake actuator.
3. Measure voltage between terminal "3" and "4" of intake actuator while operating the intake switch.

Specification : Refer the specifications in fig 3)






4. Is the measured voltage within specifications in fig 3)?

YES
a. Check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.

No
a. Substitute with a known-good actuator and check for proper operation. If the problem is corrected, replace actuator and then go to "Verification of Vehicle Repair" procedure.

Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scantool and select "Diagnostic Trouble Codes (DTCs)" mode and then clear DTC.
2. Operate the vehicle and monitor the DTC on the scantool.
3. Are any DTCs present?

YES
a. Go to the applicable troubleshooting procedure.

No
a. System is performing to specification at this time.