Vehicle Speed Signal Circuit Between Navigation Receiver Assembly And Combination Meter: Procedure

1. Drive the vehicle and check if the function of the speedometer in the combination meter assembly is normal.

   OK

   Actual vehicle speed and the speed indicated on the speedometer are the same.

   HINT: 

   • The speed indicated on the speedometer has an allowable margin of error. This can be tested using a speedometer tester (calibrated chassis dynamometer). For details about testing and the margin of error, refer to "Operation Check" in the meter/gauge system. Refer to HOW TO PROCEED WITH TROUBLESHOOTING .
   • The vehicle speed sensor is functioning normally when the indication on the speedometer is normal.

NG → See step   4 

OK: Go to next step 

1. Remove the combination meter assembly with the connector(s) still connected.
   Fig 1: Inspecting Combination Meter Assembly (Speed Signal) With Signal Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Connect an oscilloscope to terminal D18-10 (+S) and body ground.
3. Turn the ignition switch to ON.
4. Check the signal waveform according to the condition(s) in the table below.
   MEASUREMENT CONDITION
   
   

   Item	Condition
   Terminal No. (Symbols)	D18-10 (+S) - Body ground
   Tool setting	5 V/DIV., 20 msec./ DIV.
   Condition	Being driven at approx. 20 km/h (12 mph)

   HINT: 

   When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

   OK

   The waveform displayed is as shown in the illustration

   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (Combination Meter Assembly)

NG → See step   4 

OK: Go to next step 

1. Disconnect the D55 navigation receiver assembly connector.
2. Disconnect the D18 combination meter assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   D55-3 (SPD) - D18-10 (+S)	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   D55-3 (SPD) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   5