P2444
DTC P2444
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provide an overview of each diagnostic category.
DTC Descriptor
DTC P2444
- Secondary Air Injection (AIR) System Pump Stuck On
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The secondary air injection (AIR) system aids in the reduction of hydrocarbon emissions during a cold start. 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 control solenoid valve/pressure sensor assembly. The AIR control solenoid valve/pressure sensor assembly controls the flow of air from the AIR pump to the exhaust manifold. The AIR solenoid relay supplies the current needed to operate the AIR control solenoid valve/pressure sensor assembly. A pressure sensor is used to monitor the air flow from the AIR pump. The ECM supplies the internal pressure sensor with a 5-volt reference, an electrical ground, and a signal circuit.
The AIR diagnostic uses 3 phases to test the AIR system:
1. DTCs P0411 and P2430 run during Phase 1
2. DTCs P2430 and P2440 run during Phase 2
3. DTC P2444 runs during Phase 3
In all 3 phases, testing is accomplished by comparing the measured pressure against the expected pressure. The ECM can detect faults in the AIR pump, AIR control solenoid valve/pressure sensor assembly, and the exhaust check valve. The pressure sensor can also detect leaks and restrictions in the secondary AIR system plumbing.
Conditions for Running the DTC
* DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0128, P0201-P0204, P0300, P0351-P0358, P0411, P0412, P0418, P0420, P0606, P0641, P0651, P1106, P1107, P2430, P2431, P2432, P2433, 2440 are not set.
* The system voltage is 9-18 volts.
* The BARO is greater than 70 kPa.
* The MAF sensor is less than 33 g/s.
* DTC P2444 runs once per trip start up when the above conditions are met and AIR pump operation is requested.
* AIR system is commanded ON.
* Conditions are stable for greater than 5 seconds.
Conditions for Setting the DTC
* The measured AIR pressure is greater than expected.
* DTC P2444 sets within 5 seconds when the above conditions are met.
Action Taken When the DTC Sets
* The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
* The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
Conditions for Clearing the MIL/DTC
* The control module turns OFF the malfunction indicator lamp (MIL) at the beginning of the fourth ignition cycle, after 3 ignition cycles that the diagnostic runs and does not fail.
* A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
* A history DTC and related Freeze Frame data clears after 40 warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
* Clear the MIL and the DTC with a scan tool.
Reference Information
Schematic Reference
Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Verify that DTCs P0411, P0418, P0641, P0651, P2432 or P2433 are not set.
• If any of the DTCs are set, Refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).
2. Ignition ON, observe that the AIR pump is not activated.
• If the AIR pump is operating, test the AIR pump voltage supply circuit for a short to voltage. If the circuit tests normal, test the AIR pump relay control circuit for a short to ground. If the circuits test normal, test the AIR pump relay. If the relay and circuits test normal, replace the control module.
3. Ignition ON, enable and disable the AIR pump relay with a scan tool, listen for the AIR pump to turn ON and OFF.
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 data.
Circuit/System Testing
Important:
* You must perform the Circuit/System Verification before proceeding with the Circuit/System Testing.
* The AIR pump can be damaged if it fails to turn OFF. Inspect and correct the cause of an inoperable pump before replacing pump.
Ignition ON, disconnect the AIR pump harness connector. Connect a test lamp between the pump voltage supply circuit terminal A and the pump ground circuit terminal C, observe that the test lamp is not illuminated.
If the test lamp is illuminated, test for a short to voltage on the pump voltage supply circuit. If the circuit test normal, replace the AIR pump relay.
Component Testing
AIR Pump Dynamic Test
1. Install a 50A fused jumper wire between the B+ terminal and 12 volts. Install a jumper wire between the ground terminal and ground.
2. Observe for a pressurized air flow at the pump outlet.
• If a pressurized air flow is not observed, replace the AIR pump.
Relay Test
1. Test between the normally closed switch terminals, if any, for 0 ohms.
2. Test between the normally open switch terminals for infinite ohms.
3. Test between each switch terminal and either coil terminal for infinite ohms.
4. Connect the relay coil terminals to ground and fused power to energize the relay.
5. Test between each switch terminal and each coil terminal for 0 volts.
6. Test between the normally closed switch terminals, if any for infinite ohms.
7. Test between the normally open switch terminals for 0 ohms.
Repair Instructions
* Secondary Air Injection Pump Replacement (Service and Repair)
* Secondary Air Injection Check Valve Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for engine control module (ECM) replacement and programming
Repair Verification
Ignition ON, observe that the AIR pump is not operating.