GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2004 🢒 Vibe - FWD 🢒 Engine 🢒 Engine Controls - 1.8L (LNK) 🢒 DTC P2440

System Description

The DTC P2440 Secondary Air Injection (AIR) System Shut-Off Valve Stuck Open diagnostic monitors the operation of the AIR shut-off valve. The secondary AIR system helps reduce exhaust emissions. The system forces fresh filtered air into the exhaust stream in order to accelerate the catalyst operation. An electric air pump, the secondary AIR injection pump, provides filtered air on demand to the AIR shut-off valve. The AIR shut-off valve controls the flow of air from the AIR pump to the exhaust manifold. The AIR solenoid valve supplies the manifold vacuum that is used to operate the AIR shut-off valve. A pressure sensor is used to monitor the air flow from the AIR pump. By comparing the measured pressure against the expected pressure the pressure sensor can detect faults in the AIR pump, AIR shut-off valve, and the AIR solenoid valve. The pressure sensor can also detect leaks in the secondary AIR system plumbing.

Conditions for Running the DTC
    • The engine is running.
    • The secondary AIR solenoid valve is commanded OFF.
    • DTC P2440 runs continuously once the above conditions have been met.

Conditions for Setting the DTC

The pressure sensor detects exhaust gas pulsations even when the AIR shut-off valve should be CLOSED.

Action Taken When the DTC Sets
    • The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
    • The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer.

Conditions for Clearing the MIL/DTC
    • The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
    • A DTC will clear after 40 consecutive warm-up cycles have occurred without a fault.
    • A DTC can be cleared by using the scan tool Clear Information function.

Test Description

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

  1. The Diagnostic System Check-Engine Controls prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

    2.

  2. This step tests for an always ON secondary AIR solenoid valve.

    3.

  3. This step verifies the operation of the secondary AIR solenoid valve. If there is still vacuum pressure after the AIR pump is OFF, the solenoid vent passage is blocked.

    4.

  4. This step tests for a shorted solenoid control circuit.

    5.

  5. This step tests for a stuck OPEN secondary AIR shut-off 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

Install a scan tool and check for DTCs.

Is DTC P2430, P2431, P2432, or P2433 present?

Go to DTC P2430 , DTC P2431 , DTC P2432 or DTC P2433

Go to Step 3

3

  1. Disconnect the vacuum hose at the secondary AIR shut-off valve.
  2. Connect a vacuum gage the vacuum hose.
  3. Start the engine.

Is the vacuum gage indicating pressure with the engine running?

Go to Step 5

Go to Step 4

4

  1. Command the AIR solenoid valve and the AIR pump ON with the scan tool. Refer to Scan Tool Output Controls .
  2. Observe the vacuum gage when the pump is ON and after the pump turns OFF.

Did the vacuum gage indicate pressure even after the AIR pump turned OFF?

Go to Step 8

Go to Step 7

5

  1. Turn OFF the ignition.
  2. Disconnect the electrical connector of the AIR solenoid valve.
  3. Start the engine.

Does the vacuum gage still indicate pressure with the engine running?

Go to Step 8

Go to Step 6

6

  1. Test for a short to ground in the control circuit of the AIR solenoid valve. Refer to Circuit Testing in Wiring Systems.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

7

  1. Turn OFF the ignition.
  2. Remove the secondary AIR shut-off valve. Refer to Secondary Air Injection Shutoff Valve Replacement .
  3. Blow air into the large port on the AIR pump side of the AIR shut-off valve.

Does the air pass through the AIR shut-off valve?

Go to Step 9

Go to Intermittent Conditions

8

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

Did you complete the replacement?

Go to Step 11

--

9

Replace the secondary AIR shut-off valve. Refer to Secondary Air Injection Shutoff Valve Replacement .

Did you complete the replacement?

Go to Step 11

--

10

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 11

--

11
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC.

Did a DTC P2440 set?

Go to Step 2

Go to Step 12

12

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK