GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2003 🢒 DeVille 🢒 DTC 🢒 DTC P0412

Circuit Description

The secondary air injection (AIR) vacuum control solenoid is used as a switch to direct and control engine vacuum to the AIR shut-off valve.

Voltage is supplied to the AIR solenoid by the ignition 1  voltage circuit. The powertrain control module (PCM) commands the AIR solenoid ON by supplying a ground on the control circuit by an internal switch called a driver. This action completes the circuit and energizes the AIR solenoid allowing vacuum to open the shut-off valve. The PCM driver monitors the control circuit voltage constantly for proper voltage conditions. When the PCM commands the AIR solenoid ON, the circuit voltage should be low, near 0 volts. When the PCM commands the control circuit OFF, the voltage potential of the circuit should be high, near the battery voltage. If the PCM detects a voltage other than what is expected, DTC P0412 sets.

Conditions for Running the DTC
    • The engine is running.
    • The system voltage is between 8-16 volts.

Conditions for Setting the DTC
    • The PCM detects an improper voltage level on the control circuit of the AIR vacuum control solenoid valve.
    • The condition exists for at least 10 seconds.

Action Taken When the DTC Sets
    • The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails.
    • The PCM stores the conditions present when the DTC set as Freeze Frame/Failure Records data.

Conditions for Clearing the MIL/DTC
    • The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes.
    • The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • The DTC can be cleared by using the scan tool Clear DTC Information function.

Test Description

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

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

    2.

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

    3.

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

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Are DTCs P0102, P0418, or P0443 set?

Go to Step 3

Go to Step 4

3

  1. Inspect for the following conditions:
    2. • A short to ground in the ignition 1 voltage circuit
    • A shorted component that shares the IGN 1 fuse--Refer to Power Distribution Schematics in Wiring Systems.
  2. Replace the IGN 1 fuse as necessary.

Did you find and correct the condition?

Go to Step 16

Go to Inducing Intermittent Fault Conditions in Wiring Systems

4

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

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

Go to Step 5

Go to Step 6

5
  1. Review the Freeze Frame/Failure Records 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.

Does the DTC reset?

Go to Step 6

Go to Intermittent Conditions

6

  1. Turn OFF the ignition.
  2. Disconnect the AIR solenoid valve.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the AIR solenoid valve ignition 1 voltage circuit with test lamp connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems.

Does the test lamp illuminate?

Go to Step 7

Go to Step 13

7

  1. Connect a test lamp between the control circuit of the AIR solenoid valve and the ignition 1 voltage circuit of the AIR solenoid valve. Refer to Using Connector Test Adapters in Wiring Systems.
  2. Command the AIR solenoid valve ON and OFF with a scan tool.

Does the test lamp turn ON and OFF when commanded with a scan tool?

Go to Step 11

Go to Step 8

8

Does the test lamp remain illuminated with each command?

Go to Step 10

Go to Step 9

9

Test the AIR solenoid control circuit for a short to voltage an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 12

10

Test the control circuit between the AIR solenoid valve and the PCM for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 15

11

Test for an intermittent and for a poor connection at the AIR vacuum solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 14

12

Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 15

13

Repair the open or high resistance in the ignition 1 voltage circuit . Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 16

--

14

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

Did you complete the replacement?

Go to Step 16

--

15

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 16

--

16
  1. Clear the DTCs with a scan tool.
  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.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 17

17

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK