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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. 5:  DTC P2444 will locate and repair the cause of an AIR pump stuck in the ON position.
  2. 6:  Normal pressure sensor input voltage is approximately 2.6 volts with the ignition ON, the engine OFF and the AIR pump OFF.
  3. 13:  This step places a known load in the circuit in order to verify proper voltage drop. An appropriate length of secondary ignition wire may be adequate for a fixed 300 ohm resistor.
  4. 15:  The low reference, the AIR pressure signal, the 5-volt reference circuits and the PCM have tested OK. Replace the AIR control solenoid valve/pressure sensor assembly.
DTC P2430 (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. Monitor the MAP sensor and AIR pressure sensor parameters with the scan tool.
Is the difference between the values more than the specified value?		 8 kPa Go to Step 3  Go to Step 4 
3 Verify MAP sensor operation. Refer to Manifold Absolute Pressure (MAP) Sensor Diagnosis .
Was a repair necessary?		 - Go to Step 15  Go to Step 4 
4
  1. Start the engine.
  2. Monitor the DTC information with the scan tool.
Is DTC P0641 also set?		 - Go to DTC P0641 Go to Step 5 
5 
  1. Turn ON the ignition, with the engine OFF.
  2. Listen for secondary air injection (AIR) pump operation.
Is the AIR pump ON?		 - Go to DTC P2444 (L26, NU3)  Go to Step 6 
6 
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the AIR pressure sensor voltage parameter with a scan tool.
Is the pressure sensor voltage within the specified value?		 2.5-2.7 V Go to Step 7  Go to Step 8 
7
  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 amount?		 0.2 V Go to Diagnostic Aids Go to Step 8 
8
  1. Turn OFF the ignition.
  2. Disconnect the AIR control solenoid valve/pressure sensor assembly electrical connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage between the 5-volt reference circuit and a good ground.
Is the voltage more than the specified value?		 5-5.1 V Go to Step 16  Go to Step 9 
9 Is the voltage measured between the 5-volt reference circuit and a good ground in the previous step less than the specified value? 4.8-4.9 V Go to Step 17  Go to Step 10 
10 With the ignition ON, the engine OFF and the AIR control solenoid valve/pressure sensor assembly electrical connector disconnected from the previous step, measure the voltage between the low reference circuit and a good ground.
Is the voltage more than the specified value?		 0 V Go to Step 18  Go to Step 11 
11 With the ignition ON, the engine OFF and the AIR control solenoid valve/pressure sensor assembly electrical connector disconnected from the previous step. Monitor the AIR Pressure Sensor parameter.
Is the parameter more than the specified value?		 0 V Go to Step 19  Go to Step 12 
12
  1. With the ignition ON, the engine OFF and the AIR control solenoid valve/pressure sensor assembly electrical connector disconnected from the previous step, connect a fused jumper from the AIR pressure sensor circuit to the 5-volt reference circuit.
  2. Monitor the AIR Pressure Sensor parameter.
Is the parameter less than the specified value?		 5-5.1 V Go to Step 21  Go to Step 13 
13 
  1. With the ignition ON, the engine OFF and the AIR control solenoid valve/pressure sensor assembly electrical connector disconnected from the previous step, connect a 300 ohm fixed resistor between the 5-volt reference circuit and the low reference circuit.
  2. Connect a fused jumper from the AIR pressure sensor circuit to the 5-volt reference circuit at the fixed resistor.
  3. Monitor the AIR Pressure Sensor parameter.
Is the parameter less than the specified value?		 5-5.1 V Go to Step 20  Go to Step 14 
14
  1. With the ignition ON, the engine OFF and the AIR control solenoid valve/pressure sensor assembly electrical connector disconnected from the previous step, connect a 300 ohm fixed resistor between the 5-volt reference circuit and the low reference circuit.
  2. Connect a fused jumper from the AIR pressure sensor circuit to the low reference circuit at the fixed resistor.
  3. Monitor the AIR Pressure Sensor parameter.
Is the parameter more than the specified value?		 0 V Go to Step 22  Go to Step 15 
15  Replace the AIR pressure sensor. Refer to Secondary Air Injection (AIR) Shut-Off Valve Replacement .
Did you complete the replacement?		 - Go to Step 24  -
16
  1. Test the 5-volt reference circuit for high voltage. Refer to Testing for Intermittent Conditions and Poor Connections .
  2. Repair as necessary. Refer to Wiring Repairs .
Was a repair necessary?		 - Go to Step 24  Go to Step 23 
17
  1. Test the 5-volt reference circuit for high resistance and a short to ground. Refer to Testing for Intermittent Conditions and Poor Connections .
  2. Repair as necessary. Refer to Wiring Repairs .
Was a repair necessary?		 - Go to Step 24  Go to Step 23 
18
  1. Test the low reference circuit for short to voltage. Refer to Testing for Intermittent Conditions and Poor Connections .
  2. Repair as necessary. Refer to Wiring Repairs .
Was a repair necessary?		 - Go to Step 24  Go to Step 23 
19
  1. Test the AIR pressure sensor circuit for high voltage. Refer to Wiring Repairs .
  2. Repair as necessary. Refer to Wiring Repairs .
Was a repair necessary?		 - Go to Step 24  Go to Step 23 
20
  1. Test the 5-volt reference circuit for high resistance and a short to ground. Refer to Testing for Intermittent Conditions and Poor Connections .
  2. Repair as necessary. Refer to Wiring Repairs .
Was a repair necessary?		 - Go to Step 24  Go to Step 21 
21
  1. Test the AIR pressure sensor circuit for high resistance and a short to ground. Refer to Testing for Intermittent Conditions and Poor Connections .
  2. Repair as necessary. Refer to Wiring Repairs .
Was a repair necessary?		 - Go to Step 24  Go to Step 23 
22
  1. Test the low reference circuit for high resistance. Refer to Testing for Intermittent Conditions and Poor Connections .
  2. Repair as necessary. Refer to Wiring Repairs .
Was a repair necessary?		 - Go to Step 24  Go to Step 23 
23 Replace the PCM. Refer to Control Module References for replacement, setup and programming.
Did you complete the replacement?		 - Go to Step 24  -
24
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start and idle 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 25 
25 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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