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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1568 (Engine Controls Diagnostic (DTC P0172 To DTC P0455) -- 5.7L) >> Diagnosis >> DTC P0412 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 5:  This step tests for voltage to the AIR solenoid.
  2. 6:  This step verifies that the PCM is providing ground to the AIR solenoid.
  3. 7:  This step tests if a ground is constantly being applied to the AIR solenoid.
DTC P0412

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 Inspect the ENG IGN 1 fuse.
Is the ENG IGN 1 fuse open?		 Go to Step 12  Go to Step 3 
3
  1. Turn ON the ignition, with the engine OFF.
  2. Command the secondary air injection (AIR) solenoid ON and OFF with a scan tool.
  3. Listen for a click at the rear of the right front fender when the AIR solenoid operates. Repeat commands as necessary.
Does the AIR solenoid click ON and OFF when commanded with a scan tool?		 Go to Step 4  Go to Step 5 
4
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 1 minute.
  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 5  Go to Intermittent Conditions
5 
  1. Turn OFF the ignition.
  2. Disconnect the AIR solenoid valve.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition 1 voltage circuit at the AIR solenoid connector with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 6  Go to Step 13 
6 
  1. Connect a test lamp between the AIR solenoid control circuit and the ignition 1 voltage circuit at the AIR solenoid connector.
  2. Command the AIR solenoid ON and OFF with a scan tool.
Does the test lamp turn ON and OFF with each command?		 Go to Step 10  Go to Step 7 
7  Does the test lamp remain illuminated with each command of the scan tool? Go to Step 9  Go to Step 8 
8 Test the AIR solenoid control circuit for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 16  Go to Step 11 
9 Test the AIR solenoid control circuit 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 
10 Test for an intermittent and for a poor connection at the AIR 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 
11 Test for an intermittent and for a poor connection at the powertrain control module (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 
12
IMPORTANT: The ignition 1 voltage circuit of the AIR solenoid is spiced to other components of the vehicle.
Test all circuits and components that are supplied by the ENG IGN 1 fuse for excessive current draw. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?		 Go to Step 16  Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
13 Repair the open in the ignition 1 voltage circuit. Refer toWiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 16  -
14 Replace the AIR solenoid. Refer to Secondary Air Injection (AIR) Vacuum Control Solenoid Valve Replacement .
Did you complete the replacement?		 Go to Step 16  -
15 Replace the PCM. Refer to Powertrain Control Module (PCM) 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.
Does 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
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