DTC P0723 V6
DTC Description
This diagnostic procedure supports DTC P0723 Vehicle Speed Sensor Circuit Intermittent.
Circuit Description
The vehicle speed sensor (VSS) provides vehicle speed information to the transmission control module (TCM). The VSS is a permanent magnet generator. The sensor is mounted in the extension housing facing the rear internal gear which is splined to the output shaft assembly. As the output shaft and internal gear rotate, the toothed rotor of the internal gear produces AC voltage as the rotor teeth pass through the magnetic field of the sensor. The AC voltage level and the number of pulses increase as the speed of the vehicle increases. The TCM converts the voltage to vehicle speed. The TCM uses the output shaft speed signal to determine shift timing and torque converter clutch (TCC) scheduling.
If the TCM detects an unrealistic drop in output shaft speed, DTC P0723 sets. DTC P0723 is a type B DTC.
Refer to Automatic Transmission Controls Schematics , Automatic Transmission Inline 20-Way Connector End View , Automatic Transmission Internal Connector End Views , Automatic Transmission Control Module Connector End Views , and Automatic Transmission Related Connector End Views to aid in diagnosis.
Conditions for Running the DTC
| • | No DTCs P0722, P1810, P1815 or P1816. |
| • | Ignition voltage is 8-18V. |
| • | TFT is -40 to +150°C. |
| • | The engine run time is greater than 5 seconds. |
| • | The throttle position is greater than 12 percent. |
| • | The engine torque is 108-882 N·m. |
Conditions for Setting the DTC
The transmission output shaft speed drops greater than 1,000 RPM. for at least 3.4 seconds.
Action Taken When the DTC Sets
| • | The TCM illuminates the check powertrain icon during the second consecutive trip in which the conditions for setting the DTC are met. |
| • | The TCM commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
| • | The TCM calculates vehicle speed form the automatic transmission input shaft speed sensor and commanded gear. |
| • | At the time of the first failure, the TCM records the operating conditions when the conditions for setting the DTC are met. The TCM stores this information as a Failure Record. |
| • | At the time of the second failure, the ECM records the operating conditions when the conditions for setting the DTC are met. The ECM stores this information as a Freeze Frame. |
| • | The TCM stores DTC P0723 in TCM history. |
Conditions for Clearing the DTC
| • | The ECM turns off the check powertrain icon after the sixth consecutive drive trip in which the TCM does not send a check powertrain icon illumination request. |
| • | Tech 2 can clear the DTC. |
| • | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring. |
| • | The TCM cancels the default actions when the ignition is off long enough in order to power down the TCM. |
Diagnostic Aids
| • | Inspect the rear internal gear teeth for damage. |
| • | Visually inspect the VSS for cracks or damage. |
| • | Ensure the VSS is properly torqued to the transmission housing. |
Test Description
The following numbers refer to the step numbers in the diagnostic table:
2 Disable the traction control system when performing this step. When the ignition key is cycled off and then cycled back on, the traction control system default to on.
3 Checks the VSS for correct resistance.
4 Checks if the VSS and associated circuits are shorted to ground.
5 Checks the VSS produces an AC voltage when the output shaft is rotated.
6 Checks the integrity of the circuits between the TCM and the VSS.
Step | Action | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Has the Diagnostic System Check been performed? | Go to Step 2 | |||||||||
2 |
Important: Before clearing the DTC, use the Tech 2 Freeze Frame/Failure Record in order to record the transmission parameters at the time the DTC set. Using Tech 2 to clear the DTC(s) erases the Freeze Frame/Failure Record records from the TCM. With the drive wheels rotating, does the Tech 2 AT Output Speed parameter drop or fluctuate more than 1,300 RPM? | Go to Step 3 | Check for an intermittent fault in the circuit, refer to Testing for Intermittent Conditions and Poor Connections | ||||||||
3 |
Does the multimeter display 976-2354 Ω? | Go to Step 4 | Go to Step 7 | ||||||||
4 |
Does the multimeter display greater than 50k Ω in both instances? | Go to Step 5 | Go to Step 7 | ||||||||
5 |
Does the multimeter display 0.3 V AC? | Go to Step 6 | Go to Step 7 | ||||||||
6 |
Did you find and correct the condition? | Go to Step 9 | Go to Step 8 | ||||||||
7 | Replace the vehicle speed sensor, refer to Vehicle Speed Sensor Replacement. Did you complete the replacement? | Go to Step 9 | -- | ||||||||
8 | Replace the TCM, refer to Transmission Control Module Replacement. Did you complete the replacement? | Go to Step 9 | -- | ||||||||
9 | Perform the following procedure in order to verify the repair:
Has the DTC P0723 set? | Go to Step 2 | Go to Step 10 | ||||||||
10 | On Tech 2 select: Diagnostic Trouble Codes/Read DTC Information. Does Tech 2 display any DTCs you have not diagnosed? | System OK | |||||||||
When all diagnosis and repairs are completed, check the system for correct operation. | |||||||||||
