DTC C1779/79: Crankshaft Position Sensor Circuit; DTC C1797/97: Crankshaft Position Sensor Circuit: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to the ON position, and push the Techstream main switch on.
3. Select the item below in the DATA LIST, and read its value displayed on the Techstream.

   Air suspension

   Item	Normal Condition
   Engine Speed	Actual engine speed

4. Check that there is no difference between the engine speed value output from the crankshaft position sensor displayed on the Techstream and the engine speed value displayed on the tachometer when driving the vehicle.

   OK

   There is almost no difference in the displayed engine speed values.

   HINT: 

   There is tolerance of +- 10 % in the tachometer indication.

NG → Go to next step 

OK → REPLACE SUSPENSION CONTROL ECU 

1. Check if the normal code is output by SFI system. Refer to DTC CHECK / CLEAR .

   OK

   No DTC output from SFI system.

NG → REPAIR CIRCUIT INDICATED BY OUTPUT CODE 

OK: Go to next step 

1. Disconnect the suspension control ECU S15 connector.
   Fig 1: Identifying Suspension Control ECU S15 Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the ECM E6 connector.
3. Measure the resistance according to the values in the table below.

   Standard resistance

   Tester Connection	Specified Condition
   S15-13 (TACH) - E6-1 (TACH)	Below 1 Ω
   S15-13 (TACH) - Body ground	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Connect the suspension control ECU S15 connector.
   Fig 2: Identifying Suspension Control ECU S15 Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Connect the ECM E6 connector.
3. Remove the ECM with connector being connected.
4. Turn the ignition switch to the ON position.
5. Check output waveform.
   1. Using an oscilloscope, connect the terminals, as shown in the chart below.

      Tester Connection
      S15-13 (TACH) - S16-1 (GND)

   2. With the engine idling, check the output waveform.
      Fig 3: Identifying Normal Signal Waveform

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK

      The output waveform appears as shown in the illustration above.

      Item	Contents
      Tool setting	5V/DIV., 10 ms./DIV.
      Vehicle condition	When engine idling

      HINT: 

      As the engine speed becomes higher, the waveform cycle gets shorter.

NG → REPLACE ECM 

OK → REPLACE SUSPENSION CONTROL ECU