Dtc C2194/94 Engine Speed Signal Error (Test Mode Dtc)

Suspension. Corolla. Zre142 Aze141
Tire Pressure Monitoring. Corolla. Zre142 Aze141

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING TECHSTREAM (ENGINE SPEED)

INSPECT TIRE PRESSURE WARNING ECU (TACH SIGNAL)

CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING ECU - ECM)

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


DESCRIPTION

The tire pressure warning ECU receives an engine speed signal from the ECM. This DTC is stored upon entering test mode, and cleared when an engine speed signal of 1000 rpm is detected for 3 seconds or more. This DTC is output only in test mode.

DTC No.
DTC Detection Condition
Trouble Area
C2194/94
Test mode procedure is performed
  1. ECM
  2. Wire harness or connector
  3. Tire pressure warning ECU

WIRING DIAGRAM


Corolla. Zre142 Aze141.Tire Pressure Monitoring.Tire Pressure Warning System. Dtc C2194/94 Engine Speed Signal Error (Test Mode Dtc)


INSPECTION PROCEDURE

NOTICE:
  1. When replacing the tire pressure warning ECU, read the transmitter IDs stored in the old ECU using Techstream and write them down before removal.
  2. It is necessary to perform initialization (COROLLA_ZRE142 RM000000XMZ07PX.html) after registration (COROLLA_ZRE142 RM000000XN108OX.html) of the transmitter IDs into the tire pressure warning ECU if the ECU has been replaced.
1.READ VALUE USING TECHSTREAM (ENGINE SPEED)

  1. Turn the ignition switch off.

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Enter the following menus: Chassis / Tire Pressure Monitor / Data List.

  1. Check that the values indicated on the Techstream 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 Techstream and on the combination meter are the same.


NG
Go to step 2
OK

USE SIMULATION METHOD TO CHECK (COROLLA_ZRE142 RM000000UZ108OX.html)

2.INSPECT TIRE PRESSURE WARNING ECU (TACH SIGNAL)


    Corolla. Zre142 Aze141.Tire Pressure Monitoring.Tire Pressure Warning System. Dtc C2194/94 Engine Speed Signal Error (Test Mode Dtc)

  1. Disconnect the E94 ECU connector.

  1. Start the engine.

  1. Check the waveform of the ECU connector using an oscilloscope while idling the engine.

    OK:
    Tester Connection
    		Condition
    		Specified Condition
    E94-4 (TACH) - E94-9 (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
Go to step 3
OK

REPLACE TIRE PRESSURE WARNING ECU (COROLLA_ZRE142 RM0000024T8027X.html)

3.CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING ECU - ECM)


    Corolla. Zre142 Aze141.Tire Pressure Monitoring.Tire Pressure Warning System. Dtc C2194/94 Engine Speed Signal Error (Test Mode Dtc)

  1. Disconnect the E94 ECU connector.

  1. Disconnect the A50 ECM connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    E94-4 (TACH) - A50-15 (TACH)
    		Always
    		Below 1 Ω
    E94-4 (TACH) - Body ground
    		Always
    		10 kΩ or higher
    Result:
    Result
    		Proceed to
    OK (for 2ZR-FE)
    		A
    OK (for 2AZ-FE)
    		B
    NG
    		C


B
REPLACE ECM (for 2ZR-FE) (COROLLA_ZRE142 RM000001CN0030X.html)

C
REPLACE ECM (for 2AZ-FE) (COROLLA_ZRE142 RM000002WT506MX.html)
A

REPAIR OR REPLACE HARNESS OR CONNECTOR