Diagnostic Aids

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help in determining how many miles since the DTC set. The Fail Counter and the Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.
The PCM 5-volt reference circuits are internally connected within the PCM. If all the Engine Oil sensor circuits check to be OK, inspect related 5-volt reference circuits. Refer to DTC P0641 in Engine Controls - 5.7L.
If there is a failure with the Check Oil indicator, more than likely it is an instrument cluster fault.
Using the Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Failure Records data can aid in determining the distance travelled since the DTC reported a pass and/or fail. Operate the vehicle within the same Failure Records 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 in Wiring Systems.
Disconnecting the cruise control module will isolate the cruise control system from the rest of the vehicle systems.

DTC P0608

Step	Action	Yes	No
Schematic Reference: Instrument Cluster Schematics Connector End View Reference: Engine Controls Connector End Views and Powertrain Control Module (PCM) Connector End Views in Engine Controls - 5.7L
1	Did you perform the Instrument Panel Cluster (IPC) Diagnostic System Check?	Go to Step 2	Go to Diagnostic System Check - Instrument Cluster
2	Install a scan tool. Raise the vehicle's 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 a manual transmission. With the scan tool, observe the Vehicle Speed parameter in the powertrain control module (PCM) Engine Data 2 data list. Does the Vehicle Speed parameter match the speedometer display?	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 3
3	Turn the ignition OFF. Disconnect the PCM connector C2. Install one lead of the J 33431-C Signal Generator Instrument Panel Tester to the vehicle speed signal circuit at the PCM harness connector, and the other lead to a good ground. Turn the ignition ON, with the engine OFF. Set the J 33431-C to generate a speedometer signal. Does the vehicle speedometer indicate approximately 55 MPH?	Go to Step 5	Go to Step 4
4	Test the vehicle speed signal circuit for an open, for a short to voltage, or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 9	Go to Step 6
5	Inspect for poor connections at harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 9	Go to Step 7
6	Inspect for poor connections at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 9	Go to Step 8
7	IMPORTANT: Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement in Engine Controls - 5.7L.Did you complete the replacement?	Go to Step 9	-
8	IMPORTANT: Perform the set up procedure for the replacement IPC. Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement .Did you complete the replacement?	Go to Step 9	-
9	Use the scan tool in order to clear the DTCs. Operate vehicle within the Conditions for Running this DTC. Does the DTC reset?	Go to Step 2	System OK