Diagnostic Aids

IMPORTANT:

Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.

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 Testing for Intermittent Conditions and Poor Connections .

DTC P0608

Step	Action	Value(s)	Yes	No
Schematic Reference: Instrument Cluster Schematics
1	Did you perform the Instrument Cluster Diagnostic System Check?	-	Go to Step 2	Go to Diagnostic System Check - Instrument Cluster
2	Turn OFF the ignition. Raise the vehicle drive wheels. Refer to Lifting and Jacking the Vehicle in General Information. Start the engine. Place the transmission into drive for an automatic transmission or third gear for manual transmission. Does the vehicle speedometer indicate a vehicle speed?	-	Go to Diagnostic Aids	Go to Step 3
3	Turn OFF the ignition. Disconnect the PCM connector C2. Turn ON the ignition, with the engine OFF. Measure the voltage from the vehicle speed signal circuit of the PCM to a good ground. Does the voltage measure greater than the specified value?	9.5 V	Go to Step 4	Go to Step 6
4	Test the vehicle speed signal circuit for a short to voltage. Refer to Circuit Testing , and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 8	Go to Step 5
5	Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections , and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 8	Go to Step 7
6	Repair the short to ground in the vehicle speed signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	-	Go to Step 8	-
7	IMPORTANT: Program the replacement PCM. Replace the PCM. Refer to: Powertrain Control Module Replacement in Engine Controls - 4.3 L Powertrain Control Module Replacement in Engine controls - 4.8 L, 5.3 L and 6.0 L Powertrain Control Module Replacement in Engine Controls - 8.1 L Did you complete the replacement?	-	Go to Step 8	-
8	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?	-	Go to Step 2	System OK