GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Corvette 🢒 Engine 🢒 Engine Controls - 5.7L 🢒 DTC P0412

Circuit Description

A voltage is directly supplied to the secondary air injection (AIR) solenoid. The powertrain control module (PCM) controls the solenoid by grounding the control circuit via an internal switch that is called a driver. The primary function of the driver is to supply the ground for the component that is being controlled. Each driver has a fault line, which the PCM monitors. When the PCM commands a component ON, the voltage of the control circuit should be low, near 0 volts. When the PCM commands the control circuit to a component OFF, the voltage potential of the circuit should be high, near the battery voltage. If the PCM receives a different voltage, from the fault detection circuit, than the expected voltage, 2 events occur. The fault line status changes, and the DTC sets.

Conditions for Running the DTC
    • The engine speed is more than 400 RPM.
    • The system voltage is between 6-18 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.
    • All of the above conditions exist for a minimum of 5 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.
    • Clear the MIL and the DTC with a scan tool.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Listen for a click when the solenoid valve operates. Verify that the ON state and the OFF state are commanded. Repeat the commands as necessary.

    2.

  2. This step tests for voltage to the AIR solenoid valve.

    3.

  3. This step verifies that the PCM is providing ground to the AIR solenoid valve.

    4.

  4. This step tests if a ground is constantly being applied to the AIR solenoid valve.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Connect a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Command the AIR solenoid valve ON and OFF with a scan tool.

Does the AIR solenoid valve turn ON and OFF with each command?

Go to Step 3

Go to Step 4

3

  1. Review the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Does the DTC set?

Go to Step 4

Go to Intermittent Conditions

4
  1. Turn OFF the ignition.
  2. Disconnect the electrical connector of the AIR solenoid valve. Refer to Secondary Air Injection Vacuum Control Solenoid Valve Replacement .
  3. Turn ON the ignition, with the ignition OFF.
  4. Test the ignition 1 voltage circuit of the AIR solenoid for an open with a test lamp connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems.

Does the test lamp illuminate?

Go to Step 5

Go to Step 11

5

  1. Connect a test lamp between the control circuit of the AIR solenoid valve and the B+ supply circuit of the AIR solenoid valve.
  2. Command the AIR solenoid valve ON and OFF with a scan tool.

Does the test lamp turn ON and OFF with each command?

Go to Step 9

Go to Step 6

6

Does the test lamp remain illuminated with each command?

Go to Step 8

Go to Step 7

7

  1. Test the control circuit of the AIR solenoid valve for an open circuit or short to voltage. Refer to Circuit Testing in Wiring Systems.
  2. Repair any conditions as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 10

8
  1. Test the control circuit of the AIR solenoid valve for a short to ground. Refer to Circuit Testing in Wiring Systems.
  2. If you find a condition, repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

9
  1. Inspect for poor connections at the AIR solenoid valve. Refer to Testing for Electrical Intermittents in Wiring Systems.
  2. If you find a condition, repair the condition as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

10
  1. Inspect for poor connections at the PCM. Refer to Testing for Electrical Intermittents in Wiring Systems.
  2. If you find a condition, repair the condition as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

11

Repair the B+ supply circuit for the AIR solenoid valve. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

--

12

Replace the AIR solenoid valve. Refer to Secondary Air Injection Vacuum Control Solenoid Valve Replacement .

Did you complete the replacement?

Go to Step 14

--

13

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 14

--

14
  1. Use a scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

Go to Step 15

Go to Step 2

15

With a scan tool, observe the stored information Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK