Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter: Procedure

1. Check the output waveform.
   Fig 1: Identifying E55 Combination Meter Connector With Waveform Graph

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Remove the combination meter assembly with the connector still connected.
   2. Connect an oscilloscope to terminal E55-36 (+S) and body ground.
   3. Turn the ignition switch to ON.
   4. Turn the wheel slowly.
   5. Check the signal waveform according to the condition(s) in the table below.

      Item	Condition
      Tool setting	5 V/DIV., 20 ms./DIV.
      Vehicle condition	Driving at approx. 20 km/h (12 mph)

      OK

      The waveform is displayed as shown in the illustration above.

      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.

NG → See step   4 

OK: Go to next step 

1. Disconnect the radio receiver connector and the combination meter assembly connector.
   Fig 2: Identifying E31 Radio Receiver Connector And E55 Combination Meter Assembly Connectors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   E32-3 (SPD) - E55-36 (+S)	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   3