System Description
The DTC P2444 Secondary Air Injection (AIR) System Pump Stuck On diagnostic monitors the AIR pump activity. 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. |
| • | DTC P2444 runs continuously once the above condition has been met. |
Conditions for Setting the DTC
The pressure sensor detects air flow even when the AIR pump is commanded OFF.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) during the second key cycle in which the diagnostic trouble code (DTC) sets. |
| • | 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. |
Diagnostic Aids
Inspect for any of the following conditions:
| • | The resistance of the AIR pump relay--The resistance across terminal 1 and terminal 2 is 85-95 ohms at 20°C (68°F). The resistance across terminal 3 and terminal 4 is infinite. |
| • | The AIR pump relays electrical contacts may be pitted and sticking. Replace the relay if tapping gently on the relay or wiggling the relay causes a change in the relays operation. |
| • | The performance of the AIR pump relay may be affected by temperature. Check the relay after sitting outside overnight and after running the engine 30 minutes. |
| • | An intermittent malfunction may be caused by a fault in an AIR system electrical circuit. Inspect the wiring harness and components for an intermittent condition. Refer to Intermittent Conditions . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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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.
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This step checks for the correct operation of the AIR pump.
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This step checks for the correct operation of the AIR pump relay.
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 | |||
Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | ||
2 | Is the AIR pump operating continuously when the ignition is ON and the engine is OFF? | Go to Step 4 | Go to Step 3 |
Did the AIR pump operate for approximately 5 seconds and then turn OFF? | Go to Diagnostic Aids | Go to Step 4 | |
Remove the AIR pump relay. Is the AIR pump still operating? | Go to Step 5 | Go to Step 6 | |
5 | Repair the short to voltage in the AIR pump supply circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 10 | -- |
6 |
Did the test lamp stay illuminated even when the relay was commanded OFF? | Go to Step 7 | Go to Step 8 |
7 |
Did you find and repair a wiring short? | Go to Step 10 | Go to Step 9 |
8 | Replace the AIR pump relay. Did you complete the repair? | Go to Step 10 | -- |
9 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the repair? | Go to Step 10 | -- |
10 |
Did a DTC P2444 set? | Go to Step 2 | Go to Step 11 |
11 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | System OK | |
