Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
DTC Descriptor
DTC P2444: Secondary Air Injection (AIR) System Pump Stuck OnDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Pressure Sensor 5-Volt Reference Voltage | P0335, P0651, P2135, P2432 | P2432 | P2431, P0651 | P2430, P2431 |
Pressure Sensor Signal | P2432 | P2432 | P2433 | P2430, P2431 |
Pressure Sensor Low Reference | -- | P2433 | -- | P0411, P2431 |
Pump Supply | P0411 | P0411 | P2444 | -- |
Pump Ground | -- | P0411 | -- | -- |
Solenoid Supply | P0411 | P0411 | P2440 | -- |
Solenoid Ground | -- | P0411 | -- | -- |
Pump Relay Coil Supply | P0102, P0412, P0418, | P0418 | P0690 | -- |
Pump Relay Control | P0418 | P0418 | P0411, P0418, P0690, P2431 | -- |
Pump Relay Switch Supply | P0411 | P0411 | -- | -- |
Solenoid Relay Coil Supply | P0412 | P0411, P0412 | P0690 | -- |
Solenoid Relay Control | P0412 | P0411, P0412 | P0411, P0412, P0690 | -- |
Solenoid Relay Switch Supply | P0411 | P0411 | -- | -- |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Key ON, Engine OFF Normal Operation Range: BARO Refer to Altitude Versus Barometric Pressure. | |||
5-Volt Reference Voltage | 40 kPa | 40 kPa | 111 kPa |
Pressure Sensor Signal | 40 kPa | 40 kPa | 145 kPa |
Low Reference | BARO | 145-150 kPa | -- |
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:
- DTCs P0411 and P2430 run during Phase 1
- DTCs P2430 and P2440 run during Phase 2
- 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 11-18 volts. |
| • | The start-up intake air temperature (IAT) is greater than 5°C (41°F). |
| • | The start-up engine coolant temperature (ECT) is between 5-80°C (41-176°F). |
| • | The BARO is more 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 more than 5 seconds. |
Conditions for Setting the DTC
| • | The ECM determines that the actual AIR system pressure is 2.5 kPa greater than the predicted AIR system pressure. |
| • | DTC P2444 sets during phase 3 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
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Circuit/System Verification
- If DTCs P0411, P0418, P0641, P0651, P2432 or P2433 are set then perform those diagnostics first.
- Ignition ON, observe that the AIR pump is not activated.
- Ignition ON, enable and disable the AIR pump relay with a scan tool, listen for the AIR pump to turn ON and OFF.
- Engine running, observe the DTC information with a scan tool. DTC P2444 should not set.
- 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.
| ⇒ | 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. |
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 B, 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
- Install a 50A fused jumper wire between the B+ terminal and 12 volts. Install a jumper wire between the ground terminal and ground.
- Observe for a pressurized air flow at the pump outlet.
| ⇒ | If a pressurized air flow is not observed, replace the AIR pump. |
Relay Test
- Test between the normally closed switch terminals, if any, for 0 ohms.
- Test between the normally open switch terminals for infinite ohms.
- Test between each switch terminal and either coil terminal for infinite ohms.
- Connect the relay coil terminals to ground and fused power to energize the relay.
- Test between each switch terminal and each coil terminal for 0 volts.
- Test between the normally closed switch terminals, if any for infinite ohms.
- Test between the normally open switch terminals for 0 ohms.
Repair Instructions
| • | Control Module References for engine control module (ECM) replacement and programming |
Repair Verification
Ignition ON, observe that the AIR pump is not operating.
