Vehicle Speed Signal Circuit between Multi-display and Combination Meter: Wiring Diagram

WARNING: This page is about a different car, the 2006 Lexus IS 350 and 2006 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Multi-Display And Combination Meter Vehicle Speed Signal Circuit - Wiring Diagram

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

CHECK OPERATION OF SPEEDOMETER
1. Drive the vehicle and check if the function of the speedometer in the combination meter is normal.
  OK: Actual vehicle speed and the speed indicated on the speedometer are the same.
  
  HINT:
  
  The vehicle speed sensor is functioning normally when the indication on the speedometer is normal.
NG: GO TO COMBINATION METER SYSTEM

OK: Go to next step.
INSPECT MULTI-DISPLAY
1. Disconnect the multi-display connector J50.
2. Measure voltage.
  1. Jack up either one of the drive wheels.
  2. Move the shift lever to the neutral position.
  3. Turn the engine switch on (IG).
    
    Fig 2: Identifying Multi-Display Connector J50
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. Measure the voltage between terminal SPD of the multi-display and body ground when the drive wheels are turned slowly.
    OK: Voltage pulses as shown in the illustration.
Fig 3: View Of Voltage Pulses/Blinking Pattern
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: REPLACE MULTI-DISPLAY

NG: Go to next step.

CHECK HARNESS AND CONNECTOR (COMBINATION METER - MULTI-DISPLAY)

Disconnect the multi-display connector J50 and combination meter connector J34.

Measure the resistance according to the value(s) in the table below.

STANDARD RESISTANCE

Tester connection	Condition	Specified condition
SPD - +S	Engine switch off	Below 1 Ω

Fig 4: Identifying Multi-Display Connector J50 And Combination Meter Connector J34

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step.

CHECK HARNESS AND CONNECTOR (COMBINATION METER - MULTI-DISPLAY)

Disconnect the multi-display connector J50 and combination meter connector J34.

Measure the resistance according to the value(s) in the table below.

STANDARD RESISTANCE

Tester connection	Condition	Specified condition
SPD - Body ground	Engine switch off	10kΩ or higher

HINT:

If the resistance between terminal SPD and body ground is less than 10 kΩ, there may be a short in a wire harness, connector, or an ECU that is connected to the SPD signal wire.

Fig 5: Identifying Multi-Display Connector J50 And Combination Meter Connector J34

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OR EACH ECU

OK: REPLACE COMBINATION METER