P0722

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

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 A/T OSS Sensor signal into a 40 pulse per revolution (PPR) 5-volt DC square wave form signal on circuit 437 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 SETTING THE DTC

^ No Manifold Absolute Pressure (MAP) DTCs P0106, P0107 or P0108.

^ No Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.) DTC P1810.

^ The Accelerator Pedal Position (APP) Angle is greater than 10%.

^ The engine torque must be 108-642 N.m (80-475 lb. ft).

^ Engine speed is greater than 475 RPM for 7 seconds.

^ The engine speed is less than 3800 RPM.

^ The Automatic Tranmission Input (Shaft) Speed (A/T ISS) Sensor speed is greater than 1500 RPM.

^ The transmission is not in Park or Neutral.

^ System voltage is 9.0-16.0 volts.

^ The OSS Sensor speed is less than 200 RPM for at least 3 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM illuminates the Malfunction Indicator Lamp (MIL).

^ The PCM commands maximum line pressure.

^ The PCM freezes shift adapts.

^ The PCM defaults to the calculated output speed value using the Input Shaft Speed Sensor values.

^ DTC P0722 is stored in PCM history.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM turns OFF the MIL after three consecutive trips without a failure reported.

^ A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.

^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS

^ Inspect the wiring at the PCM, the A/T OSS and the VSS Buffer Module connectors, and all other circuit connecting points for the following conditions:

- A bent terminal

- A backed out terminal

- A damaged terminal

- Poor terminal tension

- A chafed wire

- A broken wire inside the insulation

- Moisture intrusion

- Corrosion

^ 4WD vehicles use an in-line harness connector between the OSS Sensor harness and the transfer case extension harness.

^ When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. It may be necessary to drive the vehicle.

^ Inspect the Speed Sensor wiring for contact with sharp metal edges.

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.

15. This step verifies the PCM input controlled by the Speed Buffer.