Inspection Procedure

CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - ECM)
1. Check for open and short circuit in the harness and the connector between the suspension control ECU and ECM (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).
1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
2. OK: GO TO NEXT STEP.
INSPECT ECM (TACH OUTPUT)
1. Remove the ECM with connectors being connected.
2. Turn the ignition switch ON.
3. Connect an oscilloscope to terminal E9-5 (TACH) and E11-1 (E1) of the ECM harness side connector.
  
  Fig 1: Connecting An Oscilloscope To Terminal E9-5 (TACH) And E11-1 (E1) Of ECM Harness Side Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. With the engine idling, check the signal waveform.
  
  Fig 2: Checking Signal Waveform
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Standard: Signal waveform appears as shown in the illustration.

HINT:

As the engine speed becomes higher, the waveform cycle gets shorter.
1. NG: CHECK AND REPLACE ECM (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE )
2. OK: GO TO NEXT STEP.
  CHECK AND REPLACE SUSPENSION CONTROL ECU (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE )