DTC    P0791    Intermediate Shaft Speed Sensor "A" Circuit

DTC    P0793    Intermediate Shaft Speed Sensor "A"

for Preparation Click here


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 ECM 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.

C133216E04


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)
  1. Transmission revolution sensor (speed sensor NC)
  2. Transmission wire
  3. Wiring harness connector
  4. ECM
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 ECM detects a revolution signal from the speed sensor (NT) (input RPM). The ECM 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 ECM 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.

WIRING DIAGRAM


C239276E02


INSPECTION PROCEDURE


DATA LIST

HINT:
Using the 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.

NOTICE:
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 ignition switch off.

  3. Connect the intelligent tester to the DLC3.

  4. Turn the ignition switch to ON.

  5. Turn the intelligent tester on.

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

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

    Engine and ECT 
    Tester Display
    Measurement Item/Range
    Normal Condition
    Diagnostic Note
    SPD (NC)
    Counter Gear Speed/
    Min.: 0 rpm
    Max.: 12750 rpm
    -
    Data is displayed in increments of 50 rpm

    HINT:
    1. SPD (NC) is always 0 while driving: Open or short in the sensor or circuit.
    2. 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.
1.INSPECT TRANSMISSION REVOLUTION SENSOR (SPEED SENSOR INSTALLATION)
  1. Remove the valve body assembly.



    C133219
  1. 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


    C189545E14
  1. Disconnect the speed sensor connector from the transmission wire.

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

    Standard Resistance:
    Tester Condition
    Condition
    Specified Condition
    3 (NCO) sensor side - A-3 (NCO) wiring harness connector side
    Always
    Below 1 Ω
    4 (NCB) sensor side - A-4 (NCB) wiring harness connector 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
    Text in Illustration 
    *a
    Component without harness connected
    (Transmission Wire)
    *b
    Wiring Harness Connector Side
    *c
    Sensor Side


NG
REPLACE TRANSMISSION WIRE (Click here)
OK


3.CHECK HARNESS AND CONNECTOR (ECM - WIRING HARNESS CONNECTOR)
  1. Disconnect the ECM connector.

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

    Standard Resistance:
    Tester Condition
    Condition
    Specified Condition
    E26-118 (NCB) - E8-4 (NCB)
    Always
    Below 1 Ω
    E26-117 (NCO) - E8-3 (NCO)
    Always
    Below 1 Ω
    E26-118 (NCB) or E8-4 (NCB)- Body ground and other terminals
    Always
    10 kΩ or higher
    E26-117 (NCO) or E8-3 (NCO) - Body ground and other terminals
    Always
    10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4.INSPECT WIRING HARNESS CONNECTOR
  1. Remove the wiring harness connector.



    C239094E02
  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Condition
    Condition
    Specified Condition
    E8-3 (NCO) - A-3 (NCO)
    Always
    Below 1 Ω
    E8-4 (NCB) - A-4 (NCB)
    Always
    Below 1 Ω
    E8-3 (NCO) - All other terminals
    Always
    10 kΩ or higher
    E8-4 (NCB) - All other terminals
    Always
    10 kΩ or higher
    Text in Illustration 
    *a
    Component without harness connected
    (Wiring Harness Connector)
    *b
    ECM Side
    *c
    Transmission Wire Side


NG
REPLACE WIRING HARNESS CONNECTOR (Click here)
OK


5.REPLACE TRANSMISSION REVOLUTION SENSOR
(Click here).

NEXT


6.CHECK IF DTC OUTPUT RECURS (SEE IF DTC P0791 AND/OR P0793 IS OUTPUT AGAIN)
  1. Connect the intelligent tester to the DLC3.

  1. Start the engine and turn the intelligent tester on.

  1. Clear the DTCs (Click here).

    HINT:
    Write down the currently output DTCs before clearing them.
  1. Perform the monitor drive pattern (Click here).

  1. Enter the following menus: Powertrain / Engine and ECT / DTC.

  1. Read the DTCs using the intelligent tester.

    Result:

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


B
END
A

REPLACE ECM (Click here)