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Home >> Buick >> 2007 >> Lucerne CX >> Repair and Diagnosis >> External Pages >> Different car >> Section 149 (ENGINE CONTROL SYSTEM - 3.8L - DTC P0220 To DTC P0449) >> DTC P0411 (L26, Nu3) >> Test Description

Test Description

WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. 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. 9:  This step determines if excessive resistance on the supply voltage circuit between the AIR pump fuse and the AIR pump relay is the cause for an inoperative AIR pump. One ohm of resistance on this circuit can prevent the AIR pump from running.
  2. 13:  This step determines if excessive resistance on the AIR pump relay circuit and PCM driver is the cause for an inoperative AIR pump relay. The test lamp in series is intended to generate a electrical load on this circuit. Fifty ohms of resistance on this circuit can prevent the AIR pump relay from operating.
  3. 17:  This step determines if excessive resistance on the supply circuit is the cause for an inoperative AIR pump. One ohm of resistance on this circuit can prevent the AIR pump from running.
  4. 18:  This step determines if excessive resistance on the ground circuit is the cause for an inoperative AIR pump. One ohm of resistance on this circuit can prevent the AIR pump from running.
  5. 27:  This step commands both the AIR pump and AIR valve relays ON.
  6. 60:  This step determines if the AIR system is operating normally. When the AIR valve relay is commanded ON the AIR pump should run with the AIR control/shut-off valve OPEN.
DTC P0411 (L26, NU3)

Step Action Values Yes No
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2
  1. Turn ON the ignition, with the engine OFF.
  2. Listen for secondary air injection (AIR) pump operation.
Does the AIR pump run continuously?		 - Go to Step 3  Go to Step 4 
3 Remove the AIR pump relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) .
Does the AIR pump continue to operate?		 - Go to Step 53  Go to Step 5 
4
IMPORTANT: The AIR pump has an internal circuit breaker to protect the pump from overheating. Intermittent AIR pump operation during testing may be normal.
  1. Command the AIR pump relay ON and OFF with a scan tool.
  2. Listen for AIR pump operation.
Does the AIR pump turn ON and OFF when commanded with a scan tool?		 - Go to Step 19  Go to Step 6 
5
  1. Turn OFF the ignition.
  2. Probe the control circuit of the AIR pump relay with a test lamp that is connected to battery voltage. Refer to Probing Electrical Connectors .
Does the test lamp illuminate?		 - Go to Step 39  Go to Step 55 
6
  1. Remove the underhood fuse block cover.
  2. Inspect the fuse for the AIR pump.
Is the fuse open?		 - Go to Step 35  Go to Step 7 
7
  1. Turn ON the ignition, with the engine OFF.
  2. Probe both test points of the fuse for the AIR relays with a test light that is connected to a good ground. Refer to Probing Electrical Connectors .
Does the test lamp illuminate at both test points?		 - Go to Step 8  Go to Step 32 
8
  1. Turn OFF the ignition.
  2. Remove the AIR pump relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) .
  3. Probe the battery positive voltage circuit, switched side, of the AIR pump relay with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors .
Does the test lamp illuminate?		 - Go to Step 9  Go to Step 47 
9 
  1. Connect a J 36169-HD  Heavy Duty Fused Jumper Wire between the battery positive voltage circuit and the AIR pump supply voltage circuit at the AIR relay connector. Refer to Using Fused Jumper Wires .
  2. Measure the voltage drop from the battery positive circuit, switched side, of the AIR pump relay at the relay connector to battery voltage. Refer to Circuit Testing and Measuring Voltage Drop .
Is the voltage drop less than the specified value?		 0.6 V Go to Step 10  Go to Step 47 
10
  1. Remove the J 36169-HD  .
  2. Turn ON the ignition, with the engine OFF.
  3. Probe the ignition 1 voltage circuit, coil side, of the AIR pump relay with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors .
Does the test lamp illuminate?		 - Go to Step 11  Go to Step 49 
11 Measure the resistance of the ignition 1 voltage circuit from the AIR relay connector to the fuse for the AIR relays.
Is the resistance less than the specified value?		 10 Ω Go to Step 12  Go to Step 49 
12
  1. Probe the control circuit of the AIR pump relay with a test lamp that is connected to battery voltage. Refer to Probing Electrical Connectors .
  2. Command the AIR pump relay ON and OFF with a scan tool.
Does the test lamp turn ON and OFF when commanded with a scan tool?		 - Go to Step 13  Go to Step 31 
13  Measure the resistance of the AIR pump relay control circuit from the AIR pump relay connector to the powertrain control module (PCM) connector with a DMM. Refer to Circuit Testing .
Is the resistance less than the specified value?		 10 Ω Go to Step 14  Go to Step 48 
14
  1. Connect a J 36169-HD  between the battery positive voltage circuit, switched side and the AIR pump supply voltage circuit at the AIR pump relay connector. Refer to Using Fused Jumper Wires .
  2. Listen for AIR pump operation.
Does the AIR pump turn ON?		 - Go to Step 43  Go to Step 15 
15
  1. Ensure the J 36169-HD  is installed.
  2. Disconnect the AIR pump connector.
  3. Probe the AIR pump supply voltage circuit with a test lamp connected to a good ground. Refer to Probing Electrical Connectors .
Does the test lamp illuminate?		 - Go to Step 16  Go to Step 50 
16 Connect a test lamp between the AIR pump supply voltage circuit and the AIR pump ground circuit at the AIR pump harness connector.
Does the test lamp illuminate?		 - Go to Step 17  Go to Step 51 
17 
  1. Remove the J 36169-HD  from the relay connector.
  2. Connect a J 35616  GM Approved Terminal Test Kit to each of the terminals at the AIR pump harness connector and the corresponding terminal at the AIR pump. Refer to Using Connector Test Adapters .
  3. Connect the fused jumper wire J 36169-HD  at the AIR pump relay connector.
  4. Measure the voltage drop from the AIR pump supply circuit of the AIR pump connector to the AIR pump supply circuit at the AIR pump relay, with a DMM. Refer to Measuring Voltage Drop .
Is the voltage drop less than the specified value?		 0.6 V Go to Step 18  Go to Step 50 
18  Measure the voltage drop from the AIR pump ground circuit of the AIR pump, to a good ground with a DMM. Refer to Measuring Voltage Drop .
Is the voltage drop less than the specified value?		 0.6 V Go to Step 44  Go to Step 51 
19
  1. Start and idle the engine.
    2. IMPORTANT: The AIR diagnostic may command either or both the AIR pump relay and AIR valve relay ON when the engine is started. Allow the engine to operate approximately 2 minutes before commanding the AIR relays with the scan tool.
  2. Monitor the AIR Pressure Sensor parameter.
    3. IMPORTANT: When the AIR pump relay is commanded ON with the scan tool, only the AIR pump relay is energized. When the AIR valve relay is commanded ON with the scan tool, both the AIR pump and the AIR valve relays are energized.
  3. Command the AIR pump relay ON with the scan tool.
  4. Command the AIR valve relay ON with the scan tool.
  5. Subtract the maximum value measured with the AIR valve relay ON from the maximum value with the AIR pump relay ON.
Is the difference at least the specified value?		 5 kPa Go to Step 20  Go to Step 21 
20
  1. Turn OFF the ignition.
  2. Remove the electrical connectors from the PCM and the AIR control solenoid valve/pressure sensor assembly.
  3. Measure the resistance of the AIR pressure signal circuit between the PCM and the AIR control solenoid valve/pressure sensor harness terminals with a DMM.
  4. Measure the resistance of the AIR pressure sensor 5-volt reference circuit between the PCM and the AIR control solenoid valve/pressure sensor harness terminals with a DMM.
Is the resistance less than the specified value?		 10 Ω Go to Step 58  Go to Step 48 
21
  1. Turn OFF the ignition.
  2. Disconnect the AIR pump outlet hose from the AIR control solenoid valve/pressure sensor assembly.
  3. Start and idle the engine.
  4. Command the AIR pump relay ON with a scan tool.
Is a pressurized air flow present at the AIR pump outlet hose?		 - Go to Step 22  Go to Step 41 
22
  1. Turn OFF the ignition.
  2. Disconnect the AIR control solenoid valve/pressure sensor harness connector.
  3. Probe the AIR control solenoid valve/pressure sensor solenoid ground circuit with a test lamp that is connected to a battery voltage. Refer to Probing Electrical Connectors .
Does the test lamp illuminate?		 - Go to Step 23  Go to Step 48 
23
  1. Turn the ignition to the ON position.
  2. Probe the AIR control solenoid valve/pressure sensor voltage supply circuit at the AIR control solenoid valve/pressure sensor with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors .
Does the test lamp illuminate?		 - Go to Step 24  Go to Step 26 
24 Measure the resistance of the following circuits:
  • The AIR control solenoid valve/pressure sensor solenoid supply voltage
  • The AIR control solenoid valve/pressure sensor solenoid ground circuit

Is the resistance on each circuit less than the specified amount?		 10 Ω Go to Step 25  Go to Step 48 
25
  1. Ensure the AIR pump outlet hose is removed from the AIR control solenoid valve/pressure sensor.
  2. Connect a J 36169-A  Fused Jumper Wire from battery positive voltage to either terminal of the AIR control solenoid valve/pressure sensor solenoid
  3. Start and idle the engine.
  4. Momentarily touch the other solenoid terminal of the AIR control solenoid valve/pressure sensor to a good ground with a jumper wire, 5 times for a duration of 2 seconds each.
Is an exhaust sound heard at the inlet of the AIR control solenoid valve/pressure sensor assembly, each time the circuit is connected to a ground?		 - Go to Testing for Intermittent Conditions and Poor Connections Go to Step 58 
26
  1. Turn ON the ignition, with the engine OFF.
  2. Connect the AIR control solenoid valve/pressure sensor harness connector.
  3. Remove the AIR valve relay.
  4. Probe both battery positive voltage circuits at the switched side and the coil side of the AIR valve relay connector with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors .
Does the test lamp illuminate at both circuits?		 - Go to Step 27  Go to Step 54 
27 
  1. Probe the control circuit of the AIR valve relay at the underhood fuse block with a test lamp connected to battery voltage. Refer to Probing Electrical Connectors .
  2. Command the AIR valve relay ON and OFF with a scan tool.
Does the test lamp turn ON and OFF?		 - Go to Step 29  Go to Step 28 
28 Does the test lamp remain illuminated? - Go to Step 39  Go to Step 31 
29 Measure the resistance of the AIR valve relay control circuit from the AIR valve relay connector to the PCM connector with a DMM. Refer to Circuit Testing .
Is the resistance less than the specified value?		 10 Ω Go to Step 30  Go to Step 48 
30
IMPORTANT: The fuse rating shall not exceed the load rating of the jumper wire.
  1. Connect a J 36169-A  between the switched side voltage circuit and the AIR control solenoid valve/pressure sensor solenoid supply voltage circuit at the AIR valve relay connector in the underhood fuse block.
  2. Disconnect the AIR control solenoid valve/pressure sensor connector.
  3. Probe the AIR control solenoid valve/pressure sensor solenoid supply voltage circuit at the AIR control solenoid valve/pressure sensor solenoid connector with a test lamp connected to a good ground.
Does the test lamp illuminate?		 - Go to Step 46  Go to Step 52 
31 Test the AIR pump relay control circuit for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 60  Go to Step 45 
32 Does the test lamp illuminate at one side of the fuse for the AIR relays? - Go to Step 33  Go to Step 54 
33
  1. Test the AIR control solenoid valve/pressure sensor solenoid supply voltage circuit for a short to ground. Refer to Wiring Repairs and Circuit Testing .
  2. Replace the fuse for the AIR relays, as necessary.
Did you find and correct the condition?		 - Go to Step 61  Go to Step 34 
34 Measure the resistance of the AIR control solenoid valve/pressure sensor solenoid.
Is the resistance within the specified range?		 4-10 Ω Go to Step 40  Go to Step 58 
35
  1. Test the battery positive voltage circuit between the AIR pump fuse and the relay for a short to ground. Refer to Wiring Repairs and Circuit Testing .
  2. Replace the fuse for the AIR pump, as necessary.
Did you find and correct the condition?		 - Go to Step 61  Go to Step 36 
36 Test the AIR pump supply voltage circuit for a short to voltage. Refer to Wiring Repairs and Circuit Testing .
Did you find and correct the condition?		 - Go to Step 60  Go to Step 37 
37 Test the AIR pump supply voltage circuit for a short to ground. Refer to Wiring Repairs and Circuit Testing .
Did you find and correct the condition?		 - Go to Step 61  Go to Step 38 
38
  1. Install the AIR pump relay.
  2. Replace the AIR pump fuse, as necessary.
  3. Connect the AIR pump, as necessary.
  4. Start and idle the engine.
    5. IMPORTANT: The AIR diagnostic may command either or both the AIR pump relay and AIR valve relay ON when the engine is started. Allow the engine to operate approximately 2 minutes before commanding the AIR relays with the scan tool.
  5. Command the AIR pump relay ON with a scan tool.
Does the AIR pump turn ON with a scan tool?		 - Go to Testing for Intermittent Conditions and Poor Connections Go to Step 57 
39 Test the AIR pump relay control circuit for a short to ground. Refer to Wiring Repairs and Circuit Testing .
Did you find and correct the condition?		 - Go to Step 60  Go to Step 45 
40
  1. Test all of the ignition 1 voltage circuits supplied by the fuse for the AIR relays for a short to ground. Refer to Wiring Repairs and Circuit Testing .
  2. Replace the fuse for the AIR relays, as necessary.
Did you find and correct the condition?		 - Go to Step 61  Go to Testing for Intermittent Conditions and Poor Connections
41 Inspect the AIR pump outlet hose for the following conditions:
  • Restrictions
  • Leaks

Did you find and correct the condition?		 - Go to Step 61  Go to Step 42 
42 Inspect for a restriction at the following locations:
  • The AIR pump inlet hose
  • The engine air cleaner housing

Did you find and correct the condition?		 - Go to Step 61  Go to Step 57 
43 Test for an intermittent and for a poor connection at the AIR pump relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 60  Go to Step 55 
44 Test for an intermittent and for a poor connections at the AIR pump. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 60  Go to Step 57 
45 Test for shorted connections or for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 60  Go to Step 59 
46 Test for an intermittent and for a poor connection at the AIR valve relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 61  Go to Step 56 
47 Repair the open or high resistance in the battery positive circuit between the AIR pump fuse and the AIR pump relay. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 60  -
48 Repair the circuit with the open or high resistance. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 60  -
49 Repair the open or high resistance in the ignition 1 voltage circuit. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 60  -
50 Repair the open or high resistance in the AIR pump supply voltage circuit. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 60  -
51 Repair the open or high resistance in the AIR pump ground circuit. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 61  -
52 Repair the open or high resistance in the AIR control solenoid valve/pressure sensor solenoid supply voltage circuit. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 61  -
53
  1. Repair the short to voltage in the AIR pump supply voltage circuit. Refer to Wiring Repairs .
  2. Replace the fuse for the AIR relays, as necessary.
Did you complete the repair?		 - Go to Step 60  -
54 Repair the open or high resistance in the ignition 1 voltage circuit. Refer to Circuit Testing and Wiring Repairs .
Did you complete the repair?		 - Go to Step 61  -
55 Replace the AIR pump relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) .
Did you complete the replacement?		 - Go to Step 60  -
56 Replace the AIR valve relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) .
Did you complete the replacement?		 - Go to Step 61  -
57 Replace the AIR pump. Refer to Secondary Air Injection (AIR) Pump Replacement .
Did you complete the replacement?		 - Go to Step 60  -
58 Replace the AIR control solenoid valve/pressure sensor assembly. Refer to Secondary Air Injection (AIR) Shut-Off Valve Replacement .
Did you complete the replacement?		 - Go to Step 61  -
59 Replace the PCM. Refer to Control Module References for replacement, setup and programming.
Did you complete the replacement?		 - Go to Step 60  -
60 
  1. Ensure all components and connectors are installed and secured.
  2. Replace fuses, as necessary.
  3. Start and idle the engine.
    4. IMPORTANT: The AIR diagnostic may command either or both the AIR pump relay and AIR valve relay ON when the engine is started. Allow the engine to operate approximately 2 minutes before commanding the AIR relays with the scan tool.
  4. Monitor the AIR pressure sensor parameter with a scan tool.
    5. IMPORTANT: When the AIR pump relay is commanded ON with the scan tool, only the AIR pump relay is energized. When the AIR valve relay is commanded ON with the scan tool, both the AIR pump and the AIR valve relays are energized.
  5. Command the AIR pump relay ON.
  6. Command the AIR valve relay ON.
  7. Subtract the maximum AIR pressure measured with the AIR valve relay ON from the maximum AIR pressure measured with the AIR pump relay ON.
Is the difference less than the specified value?		 5 kPa Go to Step 2  Go to Step 61 
61
  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 62 
62 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List - Vehicle System OK
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