Inspection Procedure

WARNING: This page is about a different car, the 2005 Lexus RX 330. However, it is still accessible from the selected car via links, so may be relevant.

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.
1. NG: CHECK COMBINATION METER ASSY (SEE PROBLEM SYMPTOMS TABLE )
2. OK: Go to next step.
INSPECT NAVIGATION ECU
1. Disconnect the navigation ECU connector N3.
2. Measure voltage.
  1. Jack up either one of the drive wheels.
  2. Move the shift lever to the neutral position.
  3. Turn the ignition switch to the ON position.
  4. Measure the voltage between terminal SPD of the navigation ECU and body ground when the drive wheels are turned slowly.
  OK: Voltage pulses as shown below.
  
  Fig 1: Disconnecting Navigation ECU Connector N3
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: Navigation ECU Connector Terminals Voltage Graph
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: REPLACE NAVIGATION ECU (SEE NAVIGATION ECU )
2. NG: GO TO NEXT STEP.

CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSY-NAVIGATION ECU)

Disconnect the navigation ECU connector N3 and combination meter assy connector C8.

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

Standard:

NAVIGATION ECU CONNECTOR TERMINALS RESISTANCE

Tester connection	Condition	Specified condition
SPD - C8-6	Always, ignition switch OFF	Below 1 Ω

Fig 3: Disconnecting Navigation ECU Connector N3

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 4: Disconnecting Combination Meter Assy Connector C8

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step.

CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSY-NAVIGATION ECU)

Disconnect the navigation ECU connector N3 and combination meter assy connector C8.

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

Standard:

NAVIGATION ECU CONNECTOR TERMINALS RESISTANCE

Tester connection	Condition	Specified condition
SPD - Body ground	Ignition switch OFF	10 kΩ or higher

Fig 5: Disconnecting Navigation ECU Connector N3

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 ECU.

Fig 6: Disconnecting Combination Meter Assy Connector C8

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OR CHECK EACH ECU
OK: REPLACE COMBINATION METER ASSY (SEE COMBINATION METER ASSY )