Diagnostic Instructions
DTC Descriptor
DTC P0501: Vehicle Speed Sensor (VSS) Circuit
Circuit/System Description
The vehicle speed information is provided to the engine control module (ECM) by the vehicle speed sensor (VSS). The VSS is a permanent magnet generator that is mounted to the transmission and produces a pulsing voltage. The AC voltage amplitude and frequency
increases with vehicle speed. The ECM converts the pulsing voltage into km/h (mph).
Conditions for Running the DTC - European Emissions
| • | The engine speed is more than 2,500 RPM. |
| • | The air flow into the engine is greater than 180 mg/tdc. |
| • | The DTC runs continuously when the above conditions are met. |
Conditions for Running the DTC - Non-European Emissions
| • | High manifold absolute pressure readings. |
| • | The DTC runs continuously when the above conditions are met. |
Conditions for Setting the DTC - European Emissions
The ECM does not detect vehicle speed for more than 25 seconds.
Conditions for Setting the DTC - Non-European Emissions
The ECM does not detect vehicle speed for a long period of time.
Action Taken When the DTC Sets
DTC P0501 is a Type A DTC
Conditions for Clearing the DTC
DTC P0501 is a Type A DTC
Diagnostic Aids
| • | Ensure the VSS is correctly torqued to the transmission housing. |
| • | This DTC may be set due to an instrument panel (IP) cluster condition. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Circuit/System Verification
- Raise the drive wheels.
Notice: 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.
- Support the lower control arms so that the drive axles are in a horizontal position.
- Start and idle the engine.
- Engage the transmission into 2nd gear.
- Observe the VSS data parameter with a scan tool. The following should display a vehicle speed once the drive wheels are at a speed above 5 km/h (3 mph):
- If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the VSS.
- Connect a test lamp between the ignition 1 voltage circuit and ground circuit of the VSS.
- Command the fuel pump relay ON with a scan tool and load test for battery voltage between the ignition 1 voltage circuit of the VSS and ground.
| ⇒ | If less than B+, repair the ignition 1 voltage circuit of the VSS for a short to ground or an open/high resistance. |
- Ignition ON, test for less than 0.1 volt between the VSS ground circuit and the negative terminal of the battery.
| ⇒ | If greater than 0.1 volt repair the ground circuit for an open/high resistance. |
- Ignition ON, test for 9-11 volts between the signal circuit of the VSS and the negative terminal of the battery.
| ⇒ | If less than 9 volts test the VSS signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM. |
| ⇒ | If greater than 11 volts test the VSS signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM. |
- If the voltage is within the specified range replace the VSS.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
