Circuit Description
Vehicles Without ABS
The vehicle speed sensor (VSS) is mounted on the transaxle. As the transaxle turns the VSS, the VSS provides the speedometer with a vehicle speed input through voltage pulses. Each revolution of the axleshaft equals 4 pulses. This input is used to drive the speedometer.
Vehicles With ABS
The brake pressure modulator valve (BPMV) uses the wheel speed sensors to generate vehicle speed input to the speedometer, powertrain control module (PCM) and the cruise control module, if equipped.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0500 Vehicle Speed Sensor (VSS) Circuit
Condition for Running the DTC
The engine is running.
Conditions for Setting the DTC
| • | No vehicle speed sensor signal is sent to the PCM. |
| • | The park/neutral position (PNP) switch is OFF. |
| • | The engine speed is equal to or more than 2,350 RPM. |
| • | The throttle position angle is equal to or more than 13 degrees. |
| • | The engine parameters indicate the vehicle is being driven. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) the first time the diagnostic runs with the fault active. |
| • | The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer. |
Conditions for Clearing the MIL/DTC
| • | The MIL turns OFF after 3 consecutively passing trips without a fault present. |
| • | A history DTC clears after 40 consecutive warm-up cycles without a fault. |
| • | Use the scan tool Clear DTC Information function. |
Diagnostic Aids
A scan tool should indicate a vehicle speed whenever the drive wheels are turning at a speed of more than 5 km/h (3 mph). DTC P0500 can be falsely set if the engine is brake-torqued in gear. Disregard DTC P0500 if the DTC sets when the drive wheels are not turning.
An intermittent malfunction may be caused by a fault in the VSS sensor electrical circuit. Inspect the wiring harness and the components for any of the following conditions:
| • | Any backed-out terminals |
| • | Any improper mating of terminals |
| • | Any broken electrical connector locks |
| • | Any improperly formed or damaged terminals |
| • | Any faulty terminal-to-wire connections |
| • | Any physical damage to the wiring harness |
| • | A broken wire inside the insulation |
| • | Any corrosion of the electrical connections, the splices, or the terminals |
Repair any electrical circuit faults that were found. Refer to Wiring Repairs in Wiring Systems.
The information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC first set.
Test Description
The numbers below refer to the step numbers in the diagnostic table.
-
This step checks the VSS sensor for a battery positive supply.
-
This step checks the VSS sensor for a ground supply.
-
This step checks for a shorted to ground speedometer vehicle speed input circuit.
-
This step checks the VSS for an output signal.
-
This step checks the PCM vehicle speed input circuit for continuity to the speedometer.
-
This step checks the speedometer for an output signal. Each 1 hertz of frequency is approximately equal to 1 mile per hour.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Automatic Transmission Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the scan tool parameter indicate a vehicle speed? | -- | Go to Step 3 | Go to Step 4 |
3 |
Does DTC P0500 set? | -- | Go to Step 4 | Go to Diagnostic Aids |
4 |
Does the speedometer indicate a vehicle speed? | -- | Go to Step 11 | Go to Step 5 |
5 | Do all other instrument cluster assembly functions operate normally? | -- | Go to Step 6 | Go to Diagnostic Starting Point - Instrument Panel, Gages and Console in Instrument Panel, Gages, and Console |
6 | Is vehicle equipped with ABS? | -- | Go to Step 9 | Go to Step 7 |
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 13 | |
Probe the VSS connector terminal 2 on the harness side with a test lamp connected to B+. Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 14 | |
Check the VSS signal circuit between the instrument panel cluster (IPC) and the VSS or brake pressure modulator valve (BPMV). Does continuity exist? | -- | Go to Step 15 | Go to Step 10 | |
Does the DMM indicate a frequency? | -- | Go to Step 19 | Go to Step 16 | |
Is the voltage within the specified value? | 9-12 V | Go to Step 12 | Go to Step 17 | |
Does the DMM indicate a frequency? | -- | Go to Step 21 | Go to Step 18 | |
13 | Repair the cause of no power to the VSS connector. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 22 | -- |
14 | Repair the cause of no ground to the VSS connector. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 22 | -- |
15 |
Was a repair necessary? | -- | Go to Step 22 | Go to Step 19 |
16 |
Was a repair necessary? | -- | Go to Step 22 | Go to Step 20 |
17 |
If equipped, ensure that the cruise control module is not shorted internally. Was a repair necessary? | -- | Go to Step 22 | Go to Step 19 |
18 |
Was a repair necessary? | -- | Go to Step 22 | Go to Step 19 |
19 | Replace the speedometer. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console. Is the replacement complete? | -- | Go to Step 22 | -- |
20 | Replace the VSS. Refer to Vehicle Speed Sensor Replacement . Is the replacement complete? | -- | Go to Step 22 | -- |
21 | Replace the PCM. Refer to Powertrain Control Module Programming and Setup in Programming and Setup. Is the replacement complete? | -- | Go to Step 22 | -- |
22 |
Are any DTCs displayed on the scan tool? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
