Height Control Sensor Circuit: Wiring Diagram

WARNING: This page is about a different car, the 2006 Lexus GS 430 and 2006 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Height Control Sensor Circuit - Wiring Diagram

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT HEIGHT CONTROL SENSOR (FRONT LH)

Connect the 3 dry cell batteries (1.5 V) in series.
Remove the height control sensor front LH.
Connect the positive (+) lead from the battery to terminal 3 and the negative (-) lead from the battery to terminal 1.

Measure the voltage between terminals 2 and 1 while slowly moving the link up and down.

Standard voltage

STANDARD VOLTAGE SPECIFICATION

Tester Connection	Condition	Specified Condition
2 (SHFL) - 1 (SHG)	+45° (High)	Approx 4.5 V
2 (SHFL) - 1 (SHG)	0° (Normal)	Approx 2.5 V
2 (SHFL) - 1 (SHG)	-45° (Low)	Approx 0.5 V

Fig 2: Identifying (+) Lead From Battery To Terminal 3 And (-) Lead From Battery To Terminal 1

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG : REPLACE HEIGHT CONTROL SENSOR (FRONT LH)

OK : GO TO NEXT STEP

INSPECT HEIGHT CONTROL SENSOR (REAR LH)

Connect the 3 dry cell batteries (1.5 V) in series.
Remove the height control sensor rear LH.
Connect the positive (+) lead from the battery to terminal 3 and the negative (-) lead from the battery to terminal 1.

Measure the voltage between terminals 2 and 1 while slowly moving the link up and down.

Standard voltage

STANDARD VOLTAGE SPECIFICATION

Tester Connection	Condition	Specified Condition
2 (SHRL) - 1 (SHG)	+45° (High)	Approx 4.5 V
2 (SHRL) - 1 (SHG)	0° (Normal)	Approx 2.5 V
2 (SHRL) - 1 (SHG)	-45° (Low)	Approx 0.5 V

Fig 3: Identifying (+) Lead From Battery To Terminal 3 And (-) Lead From Battery To Terminal 1

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG : REPLACE HEIGHT CONTROL SENSOR (REAR LH)

OK : GO TO NEXT STEP

CHECK WIRE HARNESS (HEADLIGHT BEAM LEVEL CONTROL ECU - HEIGHT CONTROL SENSOR (FRONT LH OR REAR LH))

Check the wire harness between the headlight beam level control ECU and height control sensor (front LH).

Disconnect A43 ECU connector.
Disconnect A20 sensor connector.

Measure the resistance of the wire harness side connectors.

Standard resistance

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Specified Condition
A43-16 (SGF) - A20-1 (SHG)	Below 1 Ω
A43-18 (SHFL) - A20-2 (SHFL)	Below 1 Ω
A43-20 (SBF) - A20-3 (SHB)	Below 1 Ω
A43-16 (SGF) or A20-1 (SHG) - Body ground	10 kΩ or higher
A43-18 (SHFL) or A20-2 (SHFL) - Body ground	10 kΩ or higher
A43-20 (SBF) or A20-3 (SHB) - Body ground	10 kΩ or higher

Fig 4: Identifying A43 ECU Connector And A20 Sensor Connector

Check the wire harness between the headlight beam level control ECU and height control sensor (rear LH).

Disconnect A43 ECU connector.
Disconnect o2 sensor connector.

Measure the resistance of the wire harness side connectors.

Standard resistance

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Specified Condition
A43-17 (SGR) - o2-1 (SHG)	Below 1 Ω
A43-19 (SHRL) - o2-2 (SHRL)	Below 1 Ω
A43-21 (SBR) - o2-3 (SHB)	Below 1 Ω
A43-17 (SGR) or o2-1 (SHG) - Body ground	10 kΩ or higher
A43-19 (SHRL) or o2-2 (SHRL) - Body ground	10 kΩ or higher
A43-21 (SBR) or o2-3 (SHB) - Body ground	10 kΩ or higher

Fig 5: Identifying A43 ECU Connector And O2 Sensor Connector

NG : REPAIR OR REPLACE HARNESS AND CONNECTOR

OK : PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE