GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Corvette 🢒 Engine 🢒 Engine Controls - 5.7L 🢒 DTC P0650

Circuit Description

A voltage is supplied directly to the malfunction indicator lamp (MIL). The powertrain control module (PCM) controls the lamp by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the PCM. When the PCM is commanding a component ON, the voltage of the control circuit should be low, near 0 volts. When the PCM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high, near the battery voltage. If the fault detection circuit senses a voltage other than what is expected, the fault line status will change causing the DTC to set.

Conditions for Running the DTC
    • The engine speed is greater than 400 RPM.
    • The ignition voltage ranges between 6-18 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 above conditions exist for a minimum of 5 seconds.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

Important: 

   • Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the module. Verify that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM.
   • For any test that requires probing the PCM or probing a component harness connector, use the connector test adapter kit J 35616 . Using this kit prevents damage to the harness or component terminals. Refer to Using Connector Test Adapters in Wiring Systems.

    • If the ignition feed circuit is suspected of being open, verify that the other indicators on that circuit illuminate.
    •  For an intermittent condition, refer to Intermittent Conditions .

Test Description

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

  1. Command both the ON and the OFF states. Repeat the commands as necessary.

    2.

  2. If you do not find trouble in the control circuit or the connection at the PCM, the PCM may be faulty. However, this is an extremely unlikely failure.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

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

  1. Turn ON the ignition leaving the engine OFF.
  2. Command the lamp ON and OFF using the scan tool.

Does the lamp turn ON and OFF with each command?

Go to Diagnostic Aids

Go to Step 3

3
  1. Turn OFF the ignition.
  2. Disconnect the PCM connector C2. Refer to Powertrain Control Module Replacement .
  3. Turn ON the ignition.

Is the lamp OFF?

Go to Step 4

Go to Step 5

4

Important: If the fuse opens in the fused jumper wire, repair the circuit for a short to voltage.

Probe the lamp control circuit in the PCM harness connector with a fused jumper wire connected to ground. Refer to Using Fused Jumper Wires in Wiring Systems.

Is the lamp ON?

Go to Step 6

Go to Step 7

5

Repair the short to ground in the lamp control circuit. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 9

--

6
  1. Inspect for a poor connection at the PCM connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. If you find a poor connection, repair the connection as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

7
  1. Inspect for the following conditions:
    2. • A faulty indicator
    • An open ignition feed to the indicator
    • A control circuit that is open or shorted to B+
  2. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 9

--

8

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 9

--

9
  1. Use a scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run, and pass?

Go to Step 10

Go to Step 2

10

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK