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 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, the fault line status will change causing the DTC to set.
Conditions for Running the DTC
| • | Engine speed is greater than 600 RPM. |
| • | The ignition voltage is between 6.0 volts and 16.0 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. |
| • | The conditions are present for a minimum of 10 seconds. |
Action Taken When the DTC Sets
| • | The PCM will not command the MIL ON. The PCM stores DTC P0650 in memory when the diagnostic runs and fails. |
| • | The PCM records the conditions present at the time the diagnostic fails to the Freeze Frame. |
Conditions for Clearing the DTC
| • | A last test failed, or current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Use a scan tool in order to clear the DTC. |
Diagnostic Aids
| • | If the ignition feed circuit is suspected of being open, check if other bulbs on that circuit illuminate. |
| • | Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included in the Freeze Frame and/or Failure Records data can be useful in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same Freeze Frame conditions (RPM, load, vehicle speed, temperature etc.) that were noted. This will isolate when the DTC failed. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Command both the ON and the OFF states. Repeat the commands as necessary.
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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 | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||||
|
Important: If the I/P is completely inoperative, refer to Instrument Cluster System Check in Instrument Panel, Gauges and Console for further diagnosis.
Does the lamp turn ON and OFF with each command? | -- | Go to Diagnostic Aids | ||||||||||
3 |
Is the lamp OFF? | -- | ||||||||||
4 | 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? | -- | ||||||||||
5 | Repair the short to ground in the lamp control circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||||
6 |
Did you find and correct the condition? | -- | ||||||||||
7 | Inspect for the following conditions:
Is the repair complete? | -- | -- | |||||||||
|
Important:: Program the replacement PCM. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | -- | ||||||||||
9 |
Does the scan tool indicate that this test passed? | -- | ||||||||||
10 | 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 |
