DTC P0608 Vehicle Speed Output Circuit. Chevrolet Corvette 1999

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1999 🢒 Corvette 🢒 Engine 🢒 Engine Controls - 5.7L 🢒 DTC P0608 Vehicle Speed Output Circuit

Engine Controls Component Views
Cell 20: Park Neutral Position Switch
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

A voltage is supplied to the Vehicle Speed Output circuit. The 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 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 greater than 400 RPM.

•	The ignition voltage is greater 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 MIL/DTC

•	A last test failed (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 MIL/DTC.

Diagnostic Aids

Important:

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

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

•

Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can aid in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also aid determining how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed.

•	For an intermittent, refer to Symptoms .

Test Description

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

Further circuit diagnosis may require I/P 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 I/P diagnostic procedure.

DTC P0608 - Vehicle Speed Sensor (VSS) Output Circuit

Step

Action

Value(s)

Yes

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

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 I/P is completely inoperative, refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges, and Console.

Turn OFF the ignition.
Raise the drive wheels.
Start the engine.
Disable the traction control system.
Allow the engine to idle in gear.

Does the vehicles speedometer indicate vehicle speed?

Go to Diagnostic Aids

Go to Step 3

Turn OFF the ignition.
Disconnect the PCM connector C2 located on the opposite side of the manufacturer's logo. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement .
Install the Signal Generator Tester J 33431-B to PCM harness connector terminal containing the VSS output circuit and the other connector to ground.
Turn ON the ignition.
Turn ON the Signal Generator Tester.
Set the Signal Generator Tester to generate a vehicle speed signal.

Does the vehicle's speedometer indicate vehicle speed?

Go to Step 4

Further diagnosis of circuit required. Go to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges, and Console.

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

Did you find and correct the condition?

Go to Step 6

Go to Step 5

Important: Program the replacement PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement .

Replace the PCM.

Is the action complete?

Go to Step 6

Select the Diagnostic Trouble Code (DTC) option and the Clear DTC option using the scan tool.
Idle the engine at the normal operating temperature.
Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool.
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 7

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