P0722
DTC P0722
Circuit Description
The vehicle speed sensor (VSS) is a permanent magnet generator attached to the transmission case. The final drive assembly has a toothed wheel, VSS rotor. As the final drive assembly rotates, an AC voltage is induced and transmitted to the transmission control module (TCM). The TCM converts the AC voltage into a digital signal. The TCM uses the vehicle speed to determine shift timing, torque converter clutch apply and release, and gear ratio.
If the TCM detects a low vehicle speed and a high transmission input shaft speed while in a drive range, then DTC P0722 sets. DTC P0722 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0722 Output Speed Sensor Circuit Low Voltage
Conditions for Running the DTC
* No MAF DTCs P0101, P0102 or P0103.
* No MAP DTCs P0106, P0107 or P0108.
* No TP DTCs P0121, P0122 or P0123.
* No OSS DTC P0723.
* No AT ISS DTCs P0716 or P0717.
* The engine run time is greater than 5 seconds.
* The transmission is not in PARK or NEUTRAL.
* The TP angle is 8 percent or greater.
* The transmission input shaft speed is 1,000-5,000 RPM.
* Trans. Temp. is -40°C (-40°F) or greater.
* TCC slip speed is -20 RPM or greater.
Conditions for Setting the DTC
* The engine torque is 50-1492 N.m (37-1100 lb ft) in D4.
* The engine torque is 1492 N.m (1100 lb ft) in Park/Neutral.
* LD8: The transmission output shaft speed is 200 RPM or less for 3 seconds.
* L37: The transmission output shaft speed is 239 RPM or less for 3 seconds.
Action Taken When the DTC Sets
* The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL) 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 from the automatic transmission input, shaft, speed sensor and commanded gear.
* The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records and the TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
* The TCM stores DTC P0722 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.
Conditions for Clearing the MIL/DTC
* The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request.
* The TCM clears the DIC message when the condition no longer exists.
* A scan tool can clear the MIL/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 DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step tests for DTCs and for a vehicle speed signal. It is important to record Freeze Frame and Failure Record information before proceeding further.
5. This step tests for a resistance value greater than 1,911 ohms which would indicate an open in the high signal circuit, the low signal circuit or the VSS.
