AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P0793

DTC Code DTC Name
P0793 Intermediate Shaft Speed Sensor "A"

DESCRIPTION

This sensor detects the rotation speed of the counter gear. By comparing the counter gear speed signal (NC) with the direct clutch speed sensor signal (NT), the ECM detects the shift timing of the gears and appropriately controls the engine torque and hydraulic pressure according to various conditions. Thus smooth gear shifting is performed.

DTC No. DTC Detection Condition Trouble Area
P0793

ECM detects conditions (a), (b) and (c) continuously for 5 sec. or more: (1-trip detection logic)


  • (a) Vehicle speed: 50 km/h (31 mph) or more

  • (b) Park/neutral position switch (NSW (STAR)) is OFF

  • (c) Speed sensor (NC): less than 300 rpm

  • Open or short in transmission revolution sensor NC (speed sensor NC) circuit

  • Transmission revolution sensor NC (speed sensor NC)

  • ECM

Reference (Using an oscilloscope):

Check the waveform between terminals NC+ and NC- of the ECM connector.

A017CGYE09
Standard: Refer to the illustration.
Terminal NC+ - NC-
Tool setting 1 V/DIV, 1ms/DIV
Vehicle condition

Vehicle speed 30 km/h (19 mph): (3rd gear)

Engine speed 1400 rpm

MONITOR DESCRIPTION

The NC terminal of the ECM detects a revolution signal from the speed sensor (NC) (counter gear rpm). The ECM calculates a gearshift comparing the speed sensor (NT) with the speed sensor (NC).

While the vehicle is operating in 2nd, 3rd, 4th or 5th gear in the shift position of D, if the counter gear revolution is less than 300 rpm*1although the output shaft revolution is more than 1,000 rpm*2, the ECM detects the trouble, illuminates the MIL and stores the DTC.

*1: Pulse is not output or is irregularly output.

*2: The vehicle speed is 50 km/h (31 mph) or more.

WIRING DIAGRAM

A017B9NE87

INSPECTION PROCEDURE

Tech Tips

Using Intelligent tester to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.


  1. READ DATA LIST


    1. Warm up the engine.

    2. Turn the ignition switch off.

    3. Connect Intelligent tester to the DLC3.

    4. Turn the ignition switch on (IG).

    5. Turn on the tester.

    6. Select the item "Powertrain / Engine and ECT / Data List".

    7. According to the display on the tester, read the "Data List".

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      SPD (NC)

      Counter Gear Speed/

      display: 50 r/min

      Tech Tips

      3rd when shift lever position is D position (After warming up the engine):


      • Intermediate shaft speed (NC) becomes close to the engine speed.

      		 -

      Tech Tips


      • SPD (NC) is always 0 while driving:

        Open or short in the sensor or circuit.

      • SPD (NC) is always more than 0 and less than 300 rpm while driving the vehicle at 50 km/h (31 mph) or more:

        Sensor trouble, improper installation, or intermittent connection trouble of the circuit.

PROCEDURE


  1. INSPECT SPEED SENSOR INSTALLATION


    1. A017C02E35

      Check the speed sensor installation.

      OK
      The installation bolt is tightened properly and there is no clearance between the sensor and transaxle case.

    NG

    REPLACE SPEED SENSOR (NC) Click here

    OK

  2. INSPECT SPEED SENSOR (NC)


    1. A017G1ME69

      Disconnect the speed sensor connector from the transaxle.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      1 - 2 20°C (68°F) 560 to 680 Ω

    NG

    REPLACE SPEED SENSOR (NC) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (SPEED SENSOR - ECM)


    1. A017CYDE15

      Connect the speed sensor connector.

    2. Disconnect the ECM connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      B2-34 (NC+) - B2-26 (NC-) 20°C (68°F) 560 to 680 Ω

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

      Standard resistance (Check for short)
      Tester Connection Condition Specified Condition
      B2-34 (NC+) - Body ground Always 10 kΩ or higher
      B2-26 (NC-) - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM (for 2GR-FE) Click here