AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P0791, P0793

DTC Code DTC Name
P0791 Intermediate Shaft Speed Sensor "A" Circuit
P0793 Intermediate Shaft Speed Sensor "A"

DESCRIPTION

This sensor detects the rotation speed of the counter gear which shows the output speed of transaxle. By comparing the input turbine speed signal (NT) with the counter gear speed sensor signal (NC), the TCM detects the shift timing of the gears and appropriately controls the engine torque and hydraulic pressure according to various conditions, thus, providing smooth gear shifts.

A01I1HSE04
Text in Illustration
*1 Counter Gear *2 Clutch Drum
*3 Output Speed Sensor NC *4 Input Speed Sensor NT
DTC No. DTC Detection Condition Trouble Area
P0791 When the speed sensor input voltage is either more than 1.9 V or less than 0.1 V for 2 seconds or more. (1-trip detection logic)

  • Transmission revolution sensor (speed sensor NC)

  • Transmission wire

  • TCM
P0793 When the vehicle speed is 25 km/h (15.5 mph) or higher, the counter gear speed is less than 300 rpm for 2 seconds or more. (1-trip detection logic)

MONITOR DESCRIPTION

The NT terminal of the TCM detects a revolution signal from the speed sensor (NT) (input RPM). The TCM calculates a gear shifts by comparing the speed sensor (NT) with the speed sensor (NC).

While the vehicle is operating in 2nd, 3rd, 4th or 5th gear with the shift lever in D, if the input shaft revolution is less than 300 rpm*1 although the output shaft revolution is more than 1000 rpm*2, the TCM interprets this as a fault, 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.

MONITOR STRATEGY

Related DTCs

P0791: Speed sensor (NC)/Range check

P0793: Speed sensor (NC)/Verify pulse input
Required sensors/Components Speed sensor (NT), Speed sensor (NC)
Frequency of operation Continuous
Duration 2 sec.
MIL operation Immediate
Sequence of operation None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever this DTC is not present. None
Vehicle speed 15.5 mph (25 km/h) or more
Battery voltage 8 V or more
Engine switch on (IG)
Starter OFF

TYPICAL MALFUNCTION THRESHOLDS

P0791:
Sensor voltage Less than 0.1 V or more than 1.9 V
P0793:
Sensor signal rpm Less than 300 rpm

WIRING DIAGRAM

A01HZA8E24

INSPECTION PROCEDURE

Note

Perform the universal trip to clear permanent DTCs Click here.


  1. DATA LIST

    Tech Tips

    Using the Techstream 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.

    Note

    In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.


    1. Warm up the engine.

    2. Turn the engine switch off.

    3. Connect the Techstream to the DLC3.

    4. Turn the engine switch on (IG).

    5. Turn the Techstream on.

    6. Enter the following menus: Powertrain / ECT / Data List.

    7. According to the display on the Techstream, read the Data List.

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

      Counter gear speed/

      Min.: 0 rpm, Max.: 12750 rpm

      		 - Data is displayed in increments of 50 rpm

      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 TRANSMISSION REVOLUTION SENSOR (SPEED SENSOR INSTALLATION)


    1. Remove the valve body assembly.

    2. A01HZ6T

      Make sure that the connector is properly connected, and check the speed sensor installation Click here.

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

    NG

    REPAIR OR REPLACE TRANSMISSION REVOLUTION SENSOR Click here

    OK

  2. INSPECT TRANSMISSION WIRE


    1. A01I15PE16
      Text in Illustration
      *a

      Component without harness connected

      (Transmission Wire)
      *b TCM side
      *c Sensor Side

      Remove the TCM.

    2. Disconnect the speed sensor connector from the transmission wire.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 (NCO) sensor side - 3 (NCO) TCM side Always Below 1 Ω
      4 (NCB) sensor side - 4 (NCB) TCM side Always Below 1 Ω
      3 (NCO) sensor side - Body ground and other terminals Always 10 kΩ or higher
      4 (NCB) sensor side - Body ground and other terminals Always 10 kΩ or higher

    NG

    REPLACE TRANSMISSION WIRE Click here

    OK

  3. REPLACE TRANSMISSION REVOLUTION SENSOR

    Click here


    NEXT

  4. CHECK IF DTC OUTPUT RECURS (SEE IF DTC P0791 AND/OR P0793 IS OUTPUT AGAIN)


    1. Connect the Techstream to the DLC3.

    2. Start the engine and turn the Techstream on.

    3. Clear the DTCs Click here.

      Tech Tips

      Write down the currently output DTCs before clearing them.

    4. Perform the monitor drive pattern Click here.

    5. Enter the following menus: Powertrain / ECT / Trouble Codes.

    6. Read the DTCs using the Techstream.

      Result
      Display (DTC Output) Proceed to
      Only "P0791 or P0793" is output A
      No output B

    B

    END

    A

    REPLACE TCM Click here