The vehicle speed sensor (VSS), also called the output shaft speed sensor (OSS) creates an AC voltage as the rotor teeth pass through the magnetic field of the sensor. The transmission control module (TCM) converts the AC voltage into a vehicle speed signal, which is used to determine shift timing and torque converter clutch (TCC) scheduling. The TCM also provides a replicated transmission output speed signal (RTOSS) to the engine control module (ECM).

P150A

P150B

P150A

The replicated output speed is 60 RPM or less for 4.5 seconds.

P150B

The change in replicated output speed is 350 RPM or greater for 3.25 seconds.

P150A

P150B

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Transmission General Information

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Transmission Control Module Scan Tool Information

If there are any other engine or transmission related DTCs set, diagnose those DTCs first. With a scan tool, observe the transmission output shaft speed sensor parameter for appropriate output RPM. Then in the engine controls data list, look for a functioning signal from the TCM.

1. Ignition OFF, disconnect the ECM connector (X3).
2. Ignition ON, measure the voltage on the harness of the ECM connector (X3-66) for 5 V.

⇒	If you have 5 V, test or replace the ECM.

⇒	If the value is other than 5 V, test harness for:

•	Short to Voltage

•	Short to Ground

•

Open

3. If no trouble found, replace the TCM.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for ECM replacement, setup, and programming.