P0650

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Engine Controls Schematics: PCM Power and Grounds:

CIRCUIT DESCRIPTION
Ignition 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 solid state device 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 near 0 volts. When the PCM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be near battery voltage. If the fault detection circuit senses a voltage other than what is expected, this DTC will set.

CONDITIONS FOR RUNNING THE DTC
^ The ignition voltage is between 9.0-18.0 volts.
^ The engine speed is more than 80 RPM.
^ The PCM driver transitions from ON to OFF or from OFF to ON.

CONDITIONS FOR SETTING THE DTC
^ A short to ground, an open circuit, or a short to battery voltage is detected on the control circuit.
^ The condition is present for at least 30 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM enables the MIL when the diagnostic runs and fails. The MIL may not be able to illuminate depending on the nature of the problem.
^ The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and/or the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns the MIL OFF after three consecutive drive trips during which the diagnostic runs and passes.
^ A last test failed, or the current DTC, clears when the diagnostic runs and passes.
^ A History DTC clears after forty consecutive warm-up cycles, if no other emission related diagnostic failures are reported.
^ Use a scan tool in order to clear the MIL diagnostic trouble code.
^ Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Powertrain Control Module (PCM) Description, Clearing Diagnostic Trouble Codes.

DIAGNOSTIC AIDS

NOTE: Refer to Connector Test Adapter Kit J 35616-A Notice in Service Precautions.

IMPORTANT: The MIL is actually a Lamp Emitting Diode (LED). An LED requires a parallel dropping resistor in order to operate on a 12 volt system. If the LED burns out, the dropping resistor will still pass voltage on to the PCM, and the MIL Diagnostic Trouble Code (DTC) may not set even though the MIL is inoperative. If the power supply circuit to the indicator lamps and the MIL control circuit check out OK, the Instrument Panel (IP) cluster needs to be checked for a faulty LED. Refer to A Diagnostic System Check -instrument cluster in Instrument Panel, Gauges and Console. Instrument Panel, Gauges and Warning Indicators

If the problem is intermittent, refer to Intermittent Conditions.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
3. Normally, ignition feed voltage should be present on the control circuit with the PCM disconnected and the ignition turned ON.
4. Checks for a shorted component or a short to B+ on the control circuit. Either condition would result in a measured current of over 500 milliamps. Also checks for a component that is causing an open circuit while being operated, resulting in a measured current of 0 milliamps.
5. Checks for a short to voltage on the control circuit.
15. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.