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Home >> Buick >> 2007 >> Lucerne CX >> Repair and Diagnosis >> External Pages >> Different car >> Section 70 (Engine Control System - 3.8L (DTC P1125 To DTC P2A01)) >> Diagnosis >> DTC P2430 (L26, Nu3) >> Test Description

Test Description

WARNING: This page is about a different car, the 2005 Buick LaCrosse and 2005 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. 3:  This step determines if DTC P2430 is the result of a hard failure or an intermittent condition. Normal AIR pressure sensor voltage is approximately 2.6 volts with the ignition ON, engine OFF, and the AIR pump OFF.
  2. 5:  This step inspects for an open or a short in the pressure sensor 5-volt reference circuit.
  3. 6:  This step inspects for an open or short in the pressure sensor signal circuit.
  4. 7:  This step inspects for an open in the pressure sensor low reference circuit.
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. Start the engine.
  2. Monitor the DTC information with the scan tool.
Is DTC P0641 also set?		 - Go to DTC P0641 Go to Step 3 
3 
  1. Turn ON the ignition with the engine OFF.
  2. Monitor the AIR Pressure Sensor parameter with a scan tool.
Is the AIR Pressure Sensor Voltage parameter within the specified range?		 2.5-2.7 V Go to Step 4  Go to Step 5 
4
  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 secondary air injection (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 5 
5 
  1. Turn OFF the ignition.
  2. Disconnect the AIR control solenoid valve/pressure sensor electrical connector.
  3. Start and idle the engine.
  4. Use a DMM to measure between the 5-volt reference circuit on the harness side of the AIR control solenoid valve/pressure sensor connector and a good ground.
Is the voltage within the specified range?		 4.9-5.1 V Go to Step 6  Go to Step 7 
6  On the harness side, measure the voltage from the AIR pressure sensor circuit to the low reference circuit using a DMM.
Is the voltage less than the specified value?		 0.1 V Go to Step 9  Go to Step 8 
7  Repair the open or short to voltage in the 5-volt reference voltage circuit of the AIR pressure sensor. Refer to Wiring Repairs
Is the action complete?		 - Go to Step 14  -
8
  1. Inspect the AIR pressure sensor circuit for an open or for a short. Verify that the circuit is not shorted to ground or to the low reference circuit
  2. Repair as necessary. Refer to Wiring Repairs .
Was a repair necessary?		 - Go to Step 14  Go to Step 12 
9 Probe the AIR pressure sensor low reference circuit on the harness side with a test lamp connected to B+.
Does the test lamp illuminate?		 - Go to Step 11  Go to Step 10 
10 Repair the open in the AIR pressure sensor low reference circuit. Refer to Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 14  -
11 Replace the AIR control solenoid valve/pressure sensor assembly.
Did you complete the replacement?		 - Go to Step 14  -
12 Replace the powertrain control module (PCM). Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 13  -
13
  1. Ensure all components and connectors are installed and secured.
  2. Replace fuses, as necessary.
    3. 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.
  3. Start and idle the engine.
  4. Monitor the AIR pressure sensor voltage parameter.
    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 with the scan tool.
  6. Command the AIR valve relay ON with the scan tool.
  7. Subtract the maximum value measured with the AIR valve relay ON from the maximum value with the AIR pump relay ON.
Is the different at least the specified amount?		 0.2 V Go to Step 14  Go to Step 2 
14
  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.
Does the DTC run and pass?		 - Go to Step 15  Go to Step 02 
15 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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