P0412

CIRCUIT DESCRIPTION
The ignition voltage is supplied directly to the solenoid. The control module supplies the ground path to the solenoid control circuit via an internal solid state device called a driver. Each driver has a fault line which is monitored by the control module. When the control module commands the solenoid ON, the voltage on the control circuit should be low (near 0 volts). When the control module commands the solenoid OFF, the voltage on the control 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 control module will monitor the control circuit for the following:
^ A short to ground
^ A short to voltage
^ An open circuit
^ An open solenoid
^ An internally shorted or excessively low resistance solenoid

CONDITIONS FOR RUNNING THE DTC
^ The engine is cranking or running.
^ The system voltage is between 9-18 volts.
^ The driver changes the commanded state.

CONDITIONS FOR SETTING THE DTC
^ The control module detects an improper voltage level on the control circuit.
^ The condition exists for more than 30 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.
^ Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS

NOTE:
^ Refer to Connector Test Adapter kit J 35616-A Notice in Service Precautions.
^ Do not operate the AIR pump for more than 60 seconds. Continuous operation of the AIR pump in excess of 60 seconds will damage the AIR pump.

If the DTC cannot be duplicated and is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set. Also refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-14:

The numbers below refer to the step numbers on the diagnostic table.
1. The Diagnostic System Check-Computers and Control Systems prompts you to complete some basic checks and store the Freeze Frame/Failure Records data on the scan tool.
2. Listen for a click when the solenoid operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. This step tests for voltage at the feed.
4. This step verifies that the control module is providing a ground.
5. This step tests if ground is constantly being applied.
12. The control module utilizes Electrically Erasable Programmable Read Only Memory (EEPROM). When the control module is replaced, the new control module must be programmed.