AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P0791 and 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 indicates the output speed of the transaxle. By comparing the input turbine speed (speed sensor NT) signal with the counter gear speed (speed sensor NC) signal, the TCM detects the shift timing of the gears and appropriately controls the engine torque and hydraulic pressure according to various conditions. As a result, the gears shift smoothly.
DTC No. |
Detection Item |
DTC Detection Condition |
Trouble Area |
MIL |
Memory |
|---|---|---|---|---|---|
P0791 |
Intermediate Shaft Speed Sensor "A" Circuit |
When the speed sensor input voltage is either higher than 1.9 V or below 0.1 V for 2 seconds or more (1-trip detection logic). |
|
Comes on |
DTC stored |
P0793 |
Intermediate Shaft Speed Sensor "A" |
When the vehicle speed is 25 km/h (15.5 mph) or more, the counter gear speed is less than 300 rpm for 2 seconds or more (1-trip detection logic). |
|
Comes on |
DTC stored |
MONITOR DESCRIPTION
The NT terminal of the TCM detects a pulse signal from speed sensor NT (input RPM). The TCM calculates gear shifts by comparing the signal from speed sensor NT with the signal from 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 speed is less than 300 rpm*1 although the output shaft speed is more than 1000 rpm*2, the TCM interprets this as a fault, illuminates the MIL and stores the DTC.
*1: A pulse is not output or is irregularly output.
*2: The vehicle speed is 50 km/h (31 mph) or more.
WIRING DIAGRAM
Refer to DTC P0715.
CAUTION / NOTICE / HINT
Perform registration and/or initialization when parts related to the automatic transaxle are replaced.
DATA LIST
Tip:Using the GTS 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.
Warm up the engine.
Turn the ignition switch off.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / ECT / Data List.
According to the display on the GTS, read the Data List.
Powertrain > ECT > Data List
Tester Display
Measurement Item
Range
Normal Condition
Diagnostic Note
SPD (NC)
Counter gear speed (speed sensor NC)
Min.: 0 rpm
Max.: 12750 rpm
Vehicle stopped: 0 km/h (0 mph)
The data is displayed in increments of 50 rpm.
NC Sensor Voltage
Counter gear speed sensor (speed sensor NC) output voltage
Min.: 0 V
Max.: 5 V
Engine idling: 0.1 to 1.9 V
-
Powertrain > ECT > Data List
Tester Display
SPD (NC)
NC Sensor Voltage
Tip: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
INSPECT TRANSMISSION REVOLUTION SENSOR INSTALLATION
-
Remove the transmission valve body assembly.
Make sure that the connector is properly connected, and check the transmission revolution sensor installation.
OK
The installation bolts are tightened properly and there is no clearance between the sensor and transaxle case.
Result
Proceed to
OK
NG
-
INSPECT TRANSMISSION WIRE
-
*1
Transmission Wire
*a
Transmission Revolution Sensor Side
*b
TCM Side
Disconnect the transmission revolution sensor connector.
Remove the TCM.
Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection
Condition
Specified Condition
NCB transmission revolution sensor side - 4 (NCB) TCM side
Always
Below 1 Ω
NCO transmission revolution sensor side - 3 (NCO) TCM side
Always
Below 1 Ω
NCB transmission revolution sensor side - Body ground
Always
10 kΩ or higher
NCO transmission revolution sensor side - Body ground
Always
10 kΩ or higher
NCB transmission revolution sensor side - All other terminals except 4 (NCB) TCM side
Always
10 kΩ or higher
NCO transmission revolution sensor side - All other terminals except 3 (NCO) TCM side
Always
10 kΩ or higher
Result
Proceed to
OK
NG
-
REPLACE SPEED SENSOR NC (TRANSMISSION REVOLUTION SENSOR)
Replace the transmission revolution sensor.
Result
Proceed to
NEXT
CHECK IF DTC OUTPUT RECURS (DTC P0791 OR P0793)
Connect the GTS to the DLC3.
Start the engine and turn the GTS on.
Clear the DTCs.
Tip:Write down the currently output DTCs before clearing them.
Powertrain > ECT > Clear DTCs
Perform the monitor drive pattern.
Enter the following menus: Powertrain / ECT / Trouble Codes.
Powertrain > ECT > Trouble Codes
Read the DTCs using the GTS.
Result
Result
Proceed to
Only P0791 or P0793 is output
A
DTCs are not output
B
B END