For 1990-2009 cars

## DTC P0500 Vehicle Speed Sensor (VSS) Circuit Automatic Transmission

Engine Controls Components
Cell 21: Engine Data Sensors
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

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.

### Conditions for Running the DTC

The vehicle is operating in the fuel cutoff mode.

### Conditions for Setting the DTC

• | There is not any vehicle speed sensor signal.

• | The condition is present for more than 4 seconds.

### Action Taken When the DTC Sets

• | 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.

### Conditions for Clearing the MIL/DTC

• | 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.

### Diagnostic Aids

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.

### Test Description

The numbers below refer to the step numbers in the diagnostic table.

1. 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.

2. This step determines if the fault is present.

3. 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? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Install a scan tool.
2. Raise and suitably support vehicle drive axles. Refer to Lifting and Jacking the Vehicle in General Information.
3. Start the engine.
4. Place the gear selector in Drive.

Does the scan tool display vehicle speed above the specified value?

0 km/h (0mph)

Go to Step 3

Go to Step 4

3 |

1. Lower the vehicle.
2. Perform the Clear DTC Information function on the scan tool.
3. Operate the vehicle within the Freeze Frame conditions as specified.

Does the scan tool indicate a DTC P0500?

--

Go to Step 4

Go to Diagnostic Aids

4 |

1. Turn OFF the ignition.
2. Disconnect the vehicle speed sensor (VSS) electrical connector.
3. Use a DMM i norder to measure the resistance on the sensor side of the VSS.

Is the resistance within the specified value?

100 - 300 ohms at 20°C (68°F)

Go to Step 5

Go to Step 6

5 |

1. Check the VSS high and the VSS low circuits for an open or for a short to ground.
2. Repair the circuits as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 9

Go to Step 7

6 | Replace the VSS. Refer to Vehicle Speed Sensor Replacement . Is the action complete? | -- | Go to Step 9 | --
7 |

1. Remove the VSS.
2. Inspect the countershaft gear for any of the following conditions:

• | Damaged teeth

• | Missing teeth

• | Foreign material

3. Repair any conditions as necessary.

Was a repair necessary?

--

Go to Step 9

Go to Step 8

8 | Replace the PCM. Is the action complete? | -- | Go to Step 9 | --
9 |

1. Perform the Clear DTC Information function on the scan tool, and road-test the vehicle within the Freeze Frame conditions which set the DTC.
2. Review the scan tool data, and check the data for DTCs. The repair is complete if no DTCs are displayed.

Are any DTCs displayed on the scan tool?

--

Go to the applicable DTC table

System OK

## DTC P0500 Vehicle Speed Sensor (VSS) Circuit Manual Transmission

Engine Controls Components
Cell 21: Engine Data Sensors
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

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.

### Conditions for Running the DTC

The vehicle is operating in the fuel cutoff mode.

### Conditions for Setting the DTC

• | There is not any vehicle speed sensor signal during the fuel cutoff mode.

• | The condition is present for more than 4 seconds.

### Action Taken When the DTC Sets

• | 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.

### Conditions for Clearing the MIL/DTC

• | 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.

### Diagnostic Aids

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.

### Test Description

The numbers below refer to the step numbers in the diagnostic table.

1. 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.

2. This step determines if the fault is present.

3. 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? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Install a scan tool.
2. Raise and suitably support the vehicle drive axles. Refer to Lifting and Jacking the Vehicle in General Information.
3. Start the engine.
4. Shift the vehicle into the first gear.

Did the scan tool display a vehicle speed above the specified value?

0 km/h (0 mph)

Go to Step 3

Go to Step 4

3 |

1. Lower the vehicle.
2. Perform the Clear DTC Information function on the scan tool.
3. Operate the vehicle within Freeze Frame conditions as specified.

Does the scan tool indicate a DTC P0500?

--

Go to Step 4

Go to Diagnostic Aids

4 |

1. Turn OFF the ignition.
2. Disconnect the IP cluster assembly connector C3.
3. Use a DMM in order to measure the voltage between terminal 4, on the harness side of the IP cluster assembly connector C3, and ground.
4. Turn ON the ignition, leaving the engine OFF.

Is the voltage within the specified range?

4-6 V

Go to Step 5

Go to Step 7

5 | Probe terminal 10 of the IP cluster assembly connector C3 with a test lamp connected to B+. Did the test lamp illuminate? | -- | Go to Step 6 | Go to Step 8
6 |

1. Check the printed circuits in the instrument panel cluster assembly for cracks or for bad connections.
2. Repair as necessary. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console.

Was a repair necessary?

--

Go to Step 11

Go to Step 9

7 |

1. Check for an open or for a short in the VSS signal circuit between the VSS and the PCM.
2. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 11

Go to Step 10

8 | Repair the open or the faulty connection in the VSS ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 11 | --
9 | Replace the speedometer assembly. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console. Is the action complete? | -- | Go to Step 11 | --
10 | Replace the PCM. Is the action complete? | -- | Go to Step 11 | --
11 |

1. Perform the Clear DTC Information function on the scan tool, and road-test the vehicle within the Freeze Frame conditions which set the DTC.
2. Review the scan tool data, and check the data for DTCs. The repair is complete if no DTCs are displayed.

Are any DTCs displayed on the scan tool?

--

Go to the applicable DTC table

System OK