P0722

DTC P0722 Output Speed Sensor Low Input (Diesel Only [1 Of 2]):

DTC P0722 Output Speed Sensor Low Input (Diesel Only [2 Of 2]):

Output Speed Sensor (Diesel Only):

CIRCUIT DESCRIPTION
The speed sensor circuit consists of a magnetic induction type sensor, a Vehicle Speed Sensor (VSS) buffer module and wiring. Gear teeth pressed onto the output shaft 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 VSS signal into a 40 pulse per revolution (PPR) DC signal on circuit 437 to indicate transmission output speed.

When the 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 A DTC.

CONDITIONS FOR SETTING THE DTC

^ No Accelerator Pedal Position (APP) Sensor DTCs P0122, P0123, P0222, P0223, P0227, or P0228.
^ No Transmission Fluid Pressure Valve Position Switch (TFP Val. Position Sw.) DTC P1810.
^ The Throttle Position (TP) Sensor is greater than 12%.
^ The engine torque must be 80-450 ft lb.
^ The engine speed must be 2200-3800 RPM.
^ The Input Speed (ISS) Sensor speed is greater than 2200 RPM.
^ The transmission is not in Park or Neutral.
^ The 0SS sensor speed is less than 200 RPM for at least 3 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM defaults 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.

CONDITIONS FOR CLEARING THE DTC
1. The PCM turns OFF the Malfunction Indicator Lamp (MIL) after three consecutive ignition cycles without a failure reported.
2. 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.
3. 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 for poor electrical connections at the PCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Look 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

When diagnosing for an intermillent short or open condition, massage the wiring harness while watching the test equipment for a change.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic chart.

2. Step 2 verifies the fault condition.
3. Step 3 tests sensor integrity.