DTC C2194/94: Engine Speed Signal Error (Test Mode DTC): Procedure

1. Turn the ignition switch off.
2. Connect Techstream to the DLC3.
3. Turn the ignition switch on (IG) and turn the tester on.
4. Enter the following menus: Chassis / Tire Pressure Monitor / Data List.
5. Check that the values indicated on the tester and on the combination meter are the same.
   TIRE PRESSURE MONITOR
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Engine Speed	Engine speed/ min.: 0 RPM max.: 65535 RPM	Almost same as actual engine speed	Speed indicated on combination meter

   OK

   Engine speed indicated on the tester and on the combination meter are the same.

NG → See step   2 

OK → See step   4 

1. Disconnect the D33 ECU connector.
   Fig 1: Checking Tire Pressure Warning ECU (TACH Signal)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Start the engine.
3. Check the waveform of the ECU connector using an oscilloscope while idling the engine.

   OK

   Tester Connection	Condition	Specified Condition
   D33-4 (TACH) - D33-9 (GND)	Idling	Correct waveform appears as shown

   TOOL SETTING
   
   

   Item	Contents
   Tool Setting	5 V/DIV., 10 ms/DIV.

   HINT: 

   The wavelength becomes shorter as the engine speed increases.

NG → See step   3 

OK → See step   5 

1. Disconnect the D33 ECU connector.
   Fig 2: Checking Harness And Connector (Tire Pressure Warning ECU - ECM)

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

   Standard resistance

   2GR-FE
   
   

   Tester Connection	Condition	Specified Condition
   D33-4 (TACH) - D60-29 (TACH)	Always	Below 1 Ω
   D33-4 (TACH) - Body ground	Always	10 kΩ or higher

   1AR-FE
   
   

   Tester Connection	Condition	Specified Condition
   D33-4 (TACH) - D60-23 (TACH)	Always	Below 1 Ω
   D33-4 (TACH) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   6