P1112

CIRCUIT DESCRIPTION
The intake plenum switchover solenoid is powered by switched battery voltage from the engine controls power relay. The solenoid is activated by a control circuit from the Engine Control Module (ECM). The ECM controls the solenoid by grounding the control circuit with 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 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 the battery voltage. If the fault detection circuit senses a voltage other than what is expected, a Diagnostic Trouble Code (DTC) will set.

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

CONDITIONS FOR SETTING THE DTC
A short to ground, an open circuit, or a short to battery voltage is detected on the control circuit.

ACTION TAKEN WHEN THE DTC SETS
^ The control module stores the DTC information into memory when the diagnostic runs and fails.
^ The Malfunction Indicator Lamp (MIL) will not illuminate.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
^ The driver information center, if equipped, may display a message.

CONDITIONS FOR CLEARING THE DTC
^ 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 non-emission related diagnostic.
^ Use a scan tool in order to clear 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 any backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and 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 any 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 in order to locate the fault.

Refer to Intermittent Conditions for the intermittents. Intermittent Conditions

TEST DESCRIPTION

Steps 1-9:

Steps 10-19:

The numbers below refer to the step numbers on the diagnostic table.
2. Listen for an audible click when the solenoid operates. Repeat the commands as necessary.
3. This test can detect a partially shorted coil which would cause an excessive current flow. Leaving the circuit energized for 2 minutes allows the coil to warm up. When the coil becomes warm the coil may open causing the amps to drop to 0, or short causing the amps to go above 0.75.