P0722

DTC P0722





Test 1-8





Test 9-17

Circuit Description with 4L80-E / 4L85-E Automatic Transmission
The speed sensor circuit consists of a magnetic induction type sensor, which is the Output Shaft Speed (OSS) sensor, a Vehicle Speed Sensor (VSS) buffer module, and wiring. Gear teeth pressed onto the output shaft carrier assembly induce an alternating voltage into the sensor. This signal transmits to the VSS buffer module. The VSS buffer module compensates for various final drive ratios. The VSS buffer module also converts the AC OSS sensor signal into a 40 Pulse Per Revolution (PPR) 5 volt DC square wave form signal to indicate transmission output speed.
When the Powertrain Control Module (PCM) detects a low output speed when the vehicle has a high engine speed in a drive gear range, then DTC P0722 sets. DTC P0722 is a type B DTC.

Conditions for Running the DTC
^ No MAP DTCs P0106, P0107 or P0108.
^ No TFP manual valve position switch DTC P1810.
^ The APP angle is greater than 10 percent.
^ The engine torque must be 108 - 642 Nm (80 - 475 ft. lbs.).
^ Engine speed is greater than 475 RPM for 7 seconds.
^ The engine speed is less than 3,800 RPM.
^ The AT ISS sensor speed is greater than 1,500 RPM.
^ The transmission is not in PARK or NEUTRAL.
^ System voltage is 8 - 18 volts.

Conditions for Setting the DTC
The OSS sensor speed is less than 25 RPM for at least 3.5 seconds.

Action Taken When the DTC Sets
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) during the second consecutive trip in, which the Conditions for Setting the DTC are met.
^ The PCM commands to maximum line pressure.
^ The PCM freezes shift adapts.
^ The PCM defaults to the calculated output speed value using the input shaft speed sensor values.
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
^ The PCM stores the DTC P0722 in PCM history during the second consecutive trip in, which the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC
^ For Federal and California emissions, the PCM turns OFF the MIL during the third consecutive trip in, which the diagnostic test runs and passes.
^ A scan tool can clear the MIL/DTC.
^ For Federal and California emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring.
^ For vehicles equal to or greater than 15,000 lbs. GVW, the PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.

Diagnostic Aids
^ Inspect the speed sensor wiring for contact with sharp metal edges.
^ DTC P0722 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step verifies the fault condition.
3. This step tests sensor integrity.
9. This step verifies power and ground to the VSS buffer module.
13. This step verifies the PCM input controlled by the speed buffer.