P0503

DTC P0501 or P0503

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 Descriptors
DTC P0501
- Vehicle Speed Sensor Performance

DTC P0503
- Vehicle Speed Sensor Circuit Intermittent

Circuit/System Description

The transmission control module (TCM) provides the engine control module (ECM) vehicle speed information through the high-speed communication on the controller area network (CAN). Vehicle speed is produced by the alternating current (AC) generated through the transmission output shaft speed (OSS) sensor as the output shaft rotates. The ECM continuously monitors the vehicle speed signal supplied by the TCM.

Conditions for Running the DTC

* Engine coolant temperature is more than 39.8°C (104°F).
* No engine coolant temperature DTC is set.
* No engine speed sensor DTC is set.
* The DTCs run continuously once the above condition is met.

Conditions for Setting the DTC

P0501

The ECM detects the CAN signal is not valid for more than 2 s.

P0503

The ECM detects the vehicle speed is greater than 275 km/h (171 MPH) for more than 0.2 s.

Action Taken When the DTC Sets

* DTC P0501 is a Type C DTC.
* DTC P0503 is a Type B DTC.

Conditions for Clearing the DTC

* DTC P0501 is a Type C DTC.
* DTC P0503 is a Type B DTC.

Reference Information
Schematic Reference

Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
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)

Description and Operation

Transmission Component and System Description (Transmission Component and System Description)
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. Ignition On, observe the DTC information with a scan tool. Verify no TCM or communication DTCs are set.

• If any TCM or communication DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle) for further diagnosis.

2. Raise the drive wheels.

Caution: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the vehicle in gear with the wheels hanging down at full travel.

3. Support the lower control arms so that the drive axles are in a horizontal position.
4. Engine running, place the transmission into 2nd gear.
5. Observe the scan tool Vehicle Speed parameter. The following should display a similar vehicle speed once the drive wheels are at a speed above 5 km/h (3 MPH):

* The scan tool Vehicle Speed parameter
* The odometer

6. 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 data.

• If the DTC resets, replace the ECM.

Repair Instructions

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

* ECM or TCM-Refer to Control Module References (Programming and Relearning) for replacement, setup and programming.
* Perform the Transmission Adaptive Functions (Transmission Adaptive Functions).