Dtc C1541 Vehicle Speed Signal Malfunction

Steering. Yaris. Ncp93, 131
Power Assist Systems. Yaris. Ncp93, 131

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING TECHSTREAM (METER VEHICLE VELOCITY)

DTC C1541 Vehicle Speed Signal Malfunction

DTC C1542 Vehicle Speed Signal Malfunction

DTC C1571 Speed Sensor Malfunction (Test Mode DTC)


DESCRIPTION

Based on the vehicle speed signal received from the combination meter, the power steering ECU adjusts the amount of power assist according to vehicle speed. The power steering ECU monitors the speed signal input and stores a DTC if a malfunction is detected. While a malfunction exists in the vehicle speed signal, fail-safe operation maintains the amount of power assist at the level for a speed of 70 km/h (43 mph).
NOTICE:
Revving the engine while the vehicle is stopped may cause DTC C1541 or C1542 to be stored.
HINT:
  1. If C1541 is stored while the vehicle is stopped, driving the vehicle for 5 minutes or more and then turning the ignition switch to off will clear the DTC.
  2. If C1542 is stored while the vehicle is stopped, driving the vehicle for 5 minutes or more will clear the DTC.
  3. These DTCs are only for vehicles without a skid control ECU (ABS ECU).
  4. When the sensor is normal, a pulse signal (43 Hz at 37 mph [60 km/h]) that alternates between 0 V and 5 V is transmitted to the ECU.

DTC No.
Detection Item
Trouble Area
C1541
Vehicle Speed Signal Abnormal Increase
  1. Speed signal circuit
  2. Combination meter assembly
  3. Power steering ECU assembly
While vehicle stopped, engine rpm exceeds threshold* for 300 seconds or more, cumulative.
-
C1542
Vehicle Speed Signal Abnormal Decrease
  1. Speed signal circuit
  2. Combination meter assembly
  3. Power steering ECU assembly
While vehicle stopped, engine rpm exceeds threshold* for 30 seconds or more, cumulative.
-
C1571
Speed sensor malfunction (Test mode).
  1. Speed signal circuit
  2. Combination meter assembly
  3. Power steering ECU assembly
*Threshold: An engine speed of 4000 rpm or greater is detected within 5 minutes after engine is started, or an engine speed of 2100 rpm or greater is detected 5 minutes or more after engine is started.

Yaris. Ncp93, 131.Power Assist Systems.Power Steering System (For Sedan). Dtc C1541 Vehicle Speed Signal Malfunction


WIRING DIAGRAM


Yaris. Ncp93, 131.Power Assist Systems.Power Steering System (For Sedan). Dtc C1541 Vehicle Speed Signal Malfunction


INSPECTION PROCEDURE

HINT:
Confirm that DTC C1571 has been cleared by activating test mode after the repair is completed.
1.READ VALUE USING TECHSTREAM (METER VEHICLE VELOCITY)

  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 / EMPS / Data List / Meter Vehicle Velocity.

  1. Drive the vehicle.

  1. Read the value displayed on the Techstream.

    OK:
    Vehicle speeds displayed on Techstream and speedometer display are equal.


NG
GO TO METER / GAUGE SYSTEM (SPEED SIGNAL CIRCUIT) (YARIS_NCP93 RM000002UD7069X.html)
OK

USE SIMULATION METHOD TO CHECK (YARIS_NCP93 RM000000UZ309WX.html)