C2194

TIRE PRESSURE MONITORING: TIRE PRESSURE WARNING SYSTEM: C2194/94: Engine Speed Signal Error (Test Mode 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 signal check mode (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 signal check mode.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
* When replacing the tire pressure warning ECU, read the transmitter IDs stored in the old ECU using the Techstream and write them down before removal.
* It is necessary to perform registration Programming and Relearning of the transmitter IDs into the tire pressure warning ECU if the ECU has been replaced.

PROCEDURE

1. READ VALUE USING TECHSTREAM (ENGINE SPEED)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / Tire Pressure Monitor / Data List.

(f) Check that the values indicated on the Techstream and on the combination meter are the same.

Tire Pressure Monitor

Tire Pressure Monitor:

OK:

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

NG -- INSPECT TIRE PRESSURE WARNING ECU (TACH SIGNAL)

OK -- USE SIMULATION METHOD TO CHECK Symptom Related Diagnostic Procedures

2. INSPECT TIRE PRESSURE WARNING ECU (TACH SIGNAL)

(a) Disconnect the D31 ECU connector.





(b) Start the engine.

(c) Check the waveform of the ECU connector using an oscilloscope while idling the engine.

OK:





Text in Illustration

Text in Illustration:

Tool Setting

Tool Setting:

HINT
The wavelength becomes shorter as the engine speed increases.

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

OK -- REPLACE TIRE PRESSURE WARNING ECU Removal

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

(a) Disconnect the D31 ECU connector.





(b) Disconnect the A41 or A49 ECM connector.

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

Standard Resistance:





Text in Illustration

Text in Illustration:

Result:





C -- REPAIR OR REPLACE HARNESS OR CONNECTOR

B -- REPLACE ECM (for 1AR-FE) Removal

A -- REPLACE ECM (for 2GR-FE) Removal