6L45/6L50/6L80/6L90 - Automatic Transmission

DTC P150A or P150B

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC P150A
- Transmission Output Speed Signal Circuit

DTC P150B
- Transmission Output Speed Sensor Circuit Intermittent

Circuit/System Description

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).

Conditions for Running the DTC

P150A
* The ignition voltage is greater than 8.6 volts.
* The engine speed is greater than 500 RPM.
* The transmission output speed is greater than 1200 RPM.

P150B
* The ignition voltage is greater than 18 volts.
* The engine speed is greater than 500 RPM.
* The transmission output speed is greater than 1200 RPM.

Conditions for Setting the DTC

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.

Conditions for Clearing the DTC

P150A
* DTC P150A is a Type B DTC.
* The replicated output speed is 150 RPM or greater for at least 3 seconds.

P150B
* DTC P150B is a Type B DTC.
* Transmission output speed is 150 RPM or greater for at least 2 seconds.
* The change in transmission output speed is 150 RPM or less for at least 3 seconds.

Reference Information
Schematic Reference

Automatic Transmission Controls Schematics (6L45/6L50/6L80/6L90 - Automatic Transmission)
Connector End View Reference

* Component Connector End Views (Connector End Views By Name)
* Inline Harness Connector End Views (Connector End Views By Number)

Description and Operation

* Transmission General Description (Transmission General Description)
* Transmission Component and System Description (Transmission Component and System Description)
* Electronic Component Description (Electronic Component Description)

Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

1. If there are any other engine or transmission related DTCs set, diagnose those DTCs first.
2. Road test the vehicle from zero to 64 km/h (40 MPH). With a scan tool monitor the TCM output speed sensor and the ECM speed signal parameter values. Both parameters values should be within 3-4 km/h (2-3 MPH) of each other.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Circuit/System Testing

1. Ignition OFF, disconnect the ECM connector X1.
2. Ignition ON, test for 4.8-5.2 volts on the output speed sensor signal circuit terminal 71 and ground.

• If not within the specified range, test the output speed sensor circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the TCM.

3. If all circuits test normal, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Programming and Relearning) for ECM replacement, setup, and programming.