The vehicle speed sensor (VSS) provides the vehicle speed information to the powertrain control module (PCM). The VSS is a signal generator that produces an AC voltage. The VSS is mounted in the transaxle. The AC voltage range and the number of pulses per time period increase with the vehicle's speed.
The vehicle is operating in the fuel cutoff mode.
• | There is not any vehicle speed sensor signal. |
• | The condition is present for more than 4 seconds. |
• | The PCM illuminates the malfunction indicator lamp (MIL) after two consecutive ignition cycles in which the diagnostic runs with the fault active. |
• | The PCM records the operating conditions at the time that the diagnostic fails. The Freeze Frame buffer stores this information. |
• | The PCM enters the Fail-Safe Function and stops idle speed feedback control. |
• | The MIL turns OFF after three consecutive trips, during which the diagnostic runs and there are not any faults that are detected. |
• | A History DTC clears after 40 consecutive warm-up cycles without a fault. |
• | Use the Clear DTC Information function on the scan tool, or disconnect the PCM battery feed in order to clear the DTC. |
A fault in the VSS electrical circuit may cause an intermittent malfunction. Inspect the wiring harness and the components for any of the following conditions:
• | Backed out terminals |
• | Incorrect mating of terminals |
• | Broken electrical connector locks |
• | Incorrectly formed terminals or damaged terminals |
• | Faulty terminal-to-wire connections |
• | Physical damage to the wiring harness |
• | A broken wire inside the insulation |
• | Corrosion of electrical connections, of splices, or of terminals |
If a DTC P0500 cannot be duplicated, the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was set.
The numbers below refer to the step numbers in the diagnostic table.
The Powertrain OBD System Check prompts the technician to complete some basic checks, and to save the applicable freeze frame data on the scan tool. This creates an electronic copy of the data that was taken when the fault occurred. The scan tool saves the information for later reference.
This step determines if the fault is present.
This step checks the resistance of the VSS.
Step | Action | Value(s) | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||
2 |
Does the scan tool display vehicle speed above the specified value? | 0 km/h (0mph) | ||||||||
3 |
Does the scan tool indicate a DTC P0500? | -- | Go to Diagnostic Aids | |||||||
4 |
Is the resistance within the specified value? | 100 - 300 ohms at 20°C (68°F) | ||||||||
5 |
Was a repair necessary? | -- | ||||||||
6 | Replace the VSS. Refer to Vehicle Speed Sensor Replacement . Is the action complete? | -- | -- | |||||||
7 |
Was a repair necessary? | -- | ||||||||
8 | Replace the PCM. Is the action complete? | -- | -- | |||||||
9 |
Are any DTCs displayed on the scan tool? | -- | Go to the applicable DTC table | System OK |
The vehicle speed sensor (VSS) is located behind the instrument panel cluster assembly. The powertrain control module (PCM) supplies 5 volts to the VSS. The VSS incorporates a reed switch that opens and closes four times per revolution of the speedometer cable. The VSS signal voltage at the PCM toggles high and toggles low when the reed switch opens and closes. The PCM converts the toggled high or toggled low voltage into a vehicle speed reading.The reading is displayed in kilometers per hour and in miles per hour.
The vehicle is operating in the fuel cutoff mode.
• | There is not any vehicle speed sensor signal during the fuel cutoff mode. |
• | The condition is present for more than 4 seconds. |
• | The PCM illuminates the malfunction indicator lamp (MIL) after two consecutive ignition cycles in which the diagnostic runs with the fault active. |
• | The PCM records the operating conditions at the time that the diagnostic fails. The Freeze Frame buffer stores this information. |
• | The PCM enters the Fail-Safe Function and this function stops ISC operation. |
• | The MIL turns OFF after three consecutive trips, during which the diagnostic runs and does not detect any faults. |
• | A History DTC clears after 40 consecutive warm-up cycles without a fault. |
• | Use the Clear DTC Information function on the scan tool, or disconnect the PCM battery feed in order to clear the DTC. |
Check for a faulty speedometer cable. A binding speedometer cable may set a false DTC P0500. The speedometer cable must be free from any restrictions, and the cable must have a secure connection to the instrument panel cluster assembly.
A fault in the VSS electrical circuit may cause an intermittent malfunction. Inspect the wiring harness and the components for any of the following conditions:
• | Backed out terminals |
• | Incorrect mating of terminals |
• | Broken electrical connector locks |
• | Incorrectly formed terminals or damaged terminals |
• | Faulty terminal-to-wire connections |
• | Physical damage to the wiring harness |
• | A broken wire inside the insulation |
• | Corrosion of electrical connections, of splices, or of terminals |
If a DTC P0500 cannot be duplicated, the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was set.
The numbers below refer to the step numbers in the diagnostic table.
The Powertrain OBD System Check prompts the technician to complete some basic checks, and to save the applicable freeze frame data on the scan tool. This creates an electronic copy of the data that was taken when the fault occurred. The scan tool saves the information for later reference.
This step determines if the fault is present.
This step checks for the 5-volt reference signal from the PCM. The vehicle speed sensor (VSS) is located behind the instrument panel (IP) cluster assembly.
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 |
Did the scan tool display a vehicle speed above the specified value? | 0 km/h (0 mph) | ||
3 |
Does the scan tool indicate a DTC P0500? | -- | Go to Diagnostic Aids | |
4 |
Is the voltage within the specified range? | 4-6 V | ||
5 | Probe terminal 10 of the IP cluster assembly connector C3 with a test lamp connected to B+. Did the test lamp illuminate? | -- | ||
6 |
Was a repair necessary? | -- | ||
7 |
Was a repair necessary? | -- | ||
8 | Repair the open or the faulty connection in the VSS ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
9 | Replace the speedometer assembly. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console. Is the action complete? | -- | -- | |
10 | Replace the PCM. Is the action complete? | -- | -- | |
11 |
Are any DTCs displayed on the scan tool? | -- | Go to the applicable DTC table | System OK |