P0503
DTC P0502 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 P0502
- Vehicle Speed Sensor (VSS) Circuit - Low Voltage
DTC P0503
- Vehicle Speed Sensor (VSS) Circuit - Intermittent
Diagnostic Fault Information
Circuit/System Description
The vehicle speed sensor is provided to the engine control module by the vehicle speed sensor (VSS). The ECM provides a 5 V circuit, a low reference circuit, and a signal circuit to the VSS. The VSS provides a frequency signal that is proportional to an increase in vehicle speed.
Conditions for Running the DTC
P0502
The ignition is ON.
P0503
* Ignition voltage is between 11-18 V.
* Engine speed is between 1 500-6 500 RPMs.
* VSS signal is between 150-200 RPMs for 2 s.
Conditions for Setting the DTC
P0502
VSS signal is less than 60 RPMs for 4.5 s.
P0503
VSS signal is greater than 350 RPMs for 3.25 s.
Action Taken When the DTC Sets
P0502 and P0503 are Type B DTCs.
Conditions for Clearing the DTC
P0502 and P0503 are Type B DTCs.
Diagnostic Aids
The battery must be fully charged. Refer to Battery Inspection/Test Battery Inspection/Test.
Reference Information
Schematic Reference
Manual Transmission Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views Sunshade - Left (D61)
Description and Operation
Transmission System Description and Operation Description and Operation
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
Engine Control Module Scan Tool Information Scan Tool Testing and Procedures
Circuit/System Verification
1. Operate the vehicle on the road at various speeds up to 64 km/h (40 MPH).
2. Verify with a scan tool that the B115 Vehicle Speed Sensor parameter and the speedometer display on the instrument cluster match.
• If the parameter does not match
Refer to Circuit/System Testing.
• If the parameter matches
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.
• If the DTC resets
Refer to Circuit/System Testing.
• If the DTC does not reset
4. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the B115 Vehicle Sensor harness connector.
2. Test for less than 5 ohms between the low reference circuit terminal 2 and ground.
• If 5 ohms or greater
1. Disconnect the X3 harness connector at the K20 Engine Control Module.
2. Test for less than 2 ohms in the wire circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the wire circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.
• If less than 5 ohms
3. Ignition ON.
4. Test for greater than 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground.
• If less than 4.8 V
1. Test for infinite resistance between the 5 V reference circuit and ground.
• If less than infinite resistance repair the short to ground on the wire circuit.
• If infinite resistance
1. Disconnect the X3 harness connector at the K20 Engine Control Module.
2. Test for less than 2 ohms in the 5 V reference wire circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the wire circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.
• If greater than 5.2 V
1. Disconnect the X3 harness connector at the K20 Engine Control Module.
2. Test for less than 0.3 V between the 5 V reference circuit terminal 35 and ground.
• If 0.3 V or greater, repair the short to voltage on the wire circuit.
• If less than 0.3 V, replace the K20 Engine Control Module.
• If between 4.8-5.2 V
5. Ignition OFF.
6. Test for less than 1 V between the signal circuit terminal 3 and ground.
• If 1 V or greater
1. Disconnect the X3 harness connector at the K20 Engine Control Module.
2. Test for less than 0.3 V between the signal circuit terminal 55 and ground.
• If 0.3 V or greater, repair the short to voltage on the wire circuit.
• If less than 0.3 V, replace the K20 Engine Control Module.
• If less than 1 V
7. Ignition OFF, disconnect the X3 harness connector at the K20 Engine Control Module.
8. Test for less than 2 ohms between the signal circuit terminal 55 at the K20 Engine Control Module and the signal circuit terminal 3 at the B115 Vehicle Speed Sensor.
• If 2 ohms or greater
Repair the open/high resistance in the wire circuit.
• If less than 2 ohms
9. Test for infinite resistance between the signal circuit terminal 3 at the B115 Vehicle Speed Sensor.
• If less than infinite resistance
Repair the short to ground on the wire circuit.
• If infinite resistance
10. Replace the B115 Vehicle Speed Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Vehicle Speed Sensor Replacement Service and Repair
* Control Module References Control Module References for ECM replacement, programming and setup.