DTC P0608 Vehicle Speed Output Circuit. Oldsmobile Shelby Series 1 1999

For 1990-2009 cars
Engine Controls Components
Tach, Clutch Switch, VSS Output and VSS Signal
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice

### Circuit Description

A voltage is supplied to the vehicle speed output circuit. The powertrain control module (PCM) creates the vehicle speed output signal by pulsing the circuit to ground at a predetermined hertz rate. The PCM pulses the circuit at the same rate as the vehicle speed sensor (VSS) input signal. The PCM monitors the voltage on the vehicle speed output circuit. If the PCM determines the voltage is out of the normal operating range, a DTC sets.

### Conditions for Running the DTC

• | The engine speed is more than 400 RPM.

• | The ignition voltage is more than 6 volts but less than 18 volts.

### Conditions for Setting the DTC

• | The PCM detects that the commanded state of the driver and the actual state of the control circuit do not match.

• | All of the above conditions exist for a minimum of 5.0 seconds.

### Action Taken When the DTC Sets

• | The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails.

• | The malfunction indicator lamp (MIL) will not illuminate.

• | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.

### Conditions for Clearing the DTC

• | A last test failed, or current DTC, clears when the diagnostic runs and does not fail.

• | A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.

• | Use a scan tool in order to clear the DTC.

### Diagnostic Aids

Important:

• | Remove any debris from the PCM module connector surfaces before servicing the PCM module. Inspect the PCM module connector gaskets when diagnosing or replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM modules.

• | For any test that requires probing the PCM or a component harness connector, use the J 35616 connector test adapter kit. Using this kit prevents damage to the harness and component terminals. Refer to Using Connector Test Adapters in Wiring Systems.

For an intermittent, refer to Symptoms .

### Test Description

The number below refers to the step number on the diagnostic table.

1. Further circuit diagnosis may require instrument panel (IP) removal. The circuit from the PCM to the speedometer must be inspected for being open, shorted to ground or voltage. If you do not find any trouble, follow the appropriate IP diagnostic procedure.

#### DTC P0608 - Vehicle Speed Sensor (VSS) Output Circuit

Step | Action | Values | 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

Important::

• | DO NOT perform this test without supporting the lower control arms so that the drive axles are in a normal horizontal position. Running the vehicle with the wheels hanging down at full travel may damage the drive axles.

• | If the IP is completely inoperative, refer to A Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges, and Console.

1. Turn OFF the ignition.
2. Raise the drive wheels.
3. Start the engine.
4. Allow the engine to idle in gear.

Does the vehicles speedometer indicate vehicle speed?

--

Go to Diagnostic Aids

Go to Step 3

3

1. Turn OFF the ignition.
2. Disconnect the PCM connector C2 located on the opposite side of the manufacturer logo. Refer to Powertrain Control Module Replacement/Programming .
3. Install the J 33431-B signal generator tester to PCM harness connector terminal containing the VSS output circuit and the other connector to ground.
4. Turn ON the ignition.
5. Turn ON the J 33431-B signal generator tester.
6. Set the J 33431-B signal generator tester to generate a vehicle speed signal.

Does the vehicle speedometer indicate vehicle speed?

--

Go to Step 5

Go to Step 4

4 | Inspect for ground in the VSS output circuit. Did you find and correct the condition? | -- | Go to Step 8 | Further diagnosis of the circuit is required. Go to A diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges, and Console.

5

1. Inspect for a poor connection at the PCM connector. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.
2. If you find a poor connection repair as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 7

Go to Step 6

6 | Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | Go to Step 7 | --

7

1. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC option using the scan tool.
2. Idle the engine at the normal operating temperature.
3. Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool.
4. Operate vehicle within the conditions for running this DTC as specified in the supporting text, if applicable.

Does the scan tool indicate that this test failed?

--

Go to Step 2

Go to Step 8

8 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK