P0206

CIRCUIT DESCRIPTION
The Engine Control Module (ECM) enables an injector on the intake stroke of each cylinder. Each individual cylinder fuel control is referred to as sequential Multiport Fuel Injection (SFI).

Switched B+ voltage is supplied directly to the fuel injectors from the engine control power relay. The ECM controls each injector 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 ECM. When the ECM is commanding a component ON, the voltage of the control circuit should be low, near 0 volts. When the ECM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high, (near battery voltage. If the fault detection circuit senses a voltage other than what is expected, this Diagnostic Trouble Code (DTC) will set.

The ECM will monitor the injector circuit for the following conditions:
^ A short to ground
^ A short to voltage
^ An open circuit
^ An internally shorted or excessively low resistance injector

When the ECM detects any of the above malfunctions, this DTC will set and the affected driver will be disabled. The ECM will continue to test the circuit and if the fault goes away, the driver will be reactivated.

CONDITIONS FOR RUNNING THE DTC
^ The battery voltage is between 7.5-15 volts.
^ The engine speed is more than 40 RPM.

CONDITIONS FOR SETTING THE DTC
An injector circuit fault is detected.

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.
^ Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS
Use the J 35616-A Connector Test Adapter kit for any test that requires probing the ECM harness connector or a component harness connector.

Check for the following conditions:
^ Poor connections at the ECM or at the component-Inspect the harness connectors for a poor terminal to wire connection. Refer to Testing for Intermittent and Poor Connections in Diagrams for the proper procedure.
^ Damaged harness-Inspect the wiring harness for damage. If the harness appears to be OK, observe the scan tool while moving the related connectors and the wiring harnesses. A change in the display may help locate the fault.

Refer to Testing for Intermittent and Poor Connections in Diagrams for the intermittents.

TEST DESCRIPTION

Steps 1-9:

Steps 10-18:

The numbers below refer to the step numbers on the diagnostic table.
3. This step is to test the control circuit for a short to voltage.
6. This step is to isolate the fault to the control circuit or the ECM.
8. At this point, the fault is isolated to the engine side of the harness. This step will determine the type of fault. The upper intake will require removal in order to complete the diagnosis.