P0723

Diagnostic Chart:

Diagnostic Chart (cont'd):

Wiring Diagram:

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 an unrealistically large change in the Output Shaft Speed Sensor reading, then DTC P0723 sets. DTC P0723 is a type A DTC.

Conditions for Setting the DTC

^ No 4WD Low DTC P1875.
^ No Transmission Fluid Pressure (TFP) Val. Position Sw. assembly change for greater than 2 seconds.
^ The engine must be running.
^ The vehicle is not in 4 Wheel Drive Low.
^ RPM decrease decreases greater than 1000 RPM while in a Drive gear for at least 2 seconds.
^ The PCM sets the Malfunction Indicator Lamp (MIL).

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 Speed (ISS) Sensor values.

Conditions for Clearing the DTC

^ The PCM turns OFF the MIL after three consecutive ignition cycles 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 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 intermittent 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 table.

2. This step verifies the fault condition.
4. This step tests the voltage supply to the VSS buffer module.
7. This step tests the integrity of the ground circuit.