P0412

CIRCUIT DESCRIPTION
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 DTC will set.

The control module will monitor the control circuit for the following items:
^ 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 and 18 volts.
^ The driver changes 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 will illuminate the MIL during the second consecutive trip in which the diagnostic has been run and failed.
^ The control module will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS

NOTE: Use the connector test adapter kit for any test that requires probing the following items:
^ The PCM harness connectors
^ The electrical center fuse/relay cavities
^ The component terminals
^ The component harness connector

Using this kit will prevent damage caused by the improper probing of connector terminals.

NOTE: 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 Fail 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 an audible click when the solenoid operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. Tests for voltage at the feed.
4. Verifies that the control module is providing a ground.
5. 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.