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 System Pump A Stuck OnDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Pressure Sensor 5-Volt Reference Voltage | P2432 | P2431 | P2431 | P2430, P2431 |
Pressure Sensor Signal | P2432 | P2432 | P2433 | P2430, P2431 |
Pressure Sensor Low Reference | -- | P2433 | -- | - |
Pump Voltage Supply | P0411 | P0411 | P2444 | -- |
Pump Ground | -- | P0411 | -- | -- |
Solenoid Voltage Supply | P0411 | P0411 | P2440 | -- |
Solenoid Ground | -- | P0411 | -- | -- |
Pump Relay Coil Voltage Supply | P0411, P0418 | P0411, P0418 | -- | -- |
Pump Relay Coil Control | P0418, P2444 | P0411, P0418 | P0418 | -- |
Pump Relay Switch Supply | P0411 | P0411 | -- | -- |
Solenoid Relay Coil Voltage Supply | P0411, P0412 | P0411, P0412 | -- | -- |
Solenoid Relay Coil Control | P0412, P2440 | P0411, P0412 | P0412 | -- |
Solenoid Relay Switch Supply | P0411 | P0411 | -- | -- |
Typical Scan Tool Data
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
Operating Conditions: Key ON, Engine OFF | ||||
5-Volt Reference Voltage | BARO | 41 kPa | 41 kPa | 111 kPa |
Pressure Sensor Signal | BARO | 42 kPa | 41 kPa | 150 kPa |
Low Reference | BARO | BARO | 145 kPa | BARO |
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 valve 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 control module 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
During phase 1, both the AIR pump and the solenoid valve are activated. Normal secondary air function occurs. Expected system pressure is 8-10 kPa above BARO.
During phase 2, only the AIR pump is activated. The solenoid valve is closed. Pressure sensor performance and solenoid valve deactivation are tested. Expected system pressure is 20-25 kPa above BARO.
During phase 3, neither the AIR pump nor the solenoid valve is activated. AIR pump deactivation is tested. Expected system pressure equals BARO.
In all 3 phases, testing is accomplished by comparing the measured pressure against the expected pressure. The control module 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
| • | P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0128, P0201, P0202, P0203, P0204, P0300, P0412, P0418, P0420, P0606, P1106, P1107, P1111, P1112, P1114, P1115, P1635, P1639, P2430, P2431, P2432, P2433 are not set. |
| • | More than 60 minutes has elapsed since the last cold start. |
| • | The system voltage is 9-18 volts. |
| • | The BARO parameter is more than 70 kPa. |
| • | The MAF sensor parameter is between less than 33 g/s. |
| • | AIR system is commanded ON. |
| • | Conditions are stable for more than 5 seconds. |
| • | DTC P2444 runs once per trip start up when the above conditions are met and AIR pump operation is requested. |
Conditions for Setting the DTC
| • | The measured AIR pressure is more than expected. |
| • | DTC P2444 sets within 5 seconds when the above conditions are met. |
Action Taken When the DTC Sets
DTC P2444 is a Type A DTC.
Conditions for Clearing the MIL/DTC
DTC P2444 is a Type A DTC.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- If DTCs P0411, P0418, P2432 or P2433 are set, perform those diagnostics first.
- Engine running, command the AIR pump relay ON and OFF with a scan tool. Verify that the AIR pump turns ON and OFF with each command.
| ⇒ | If the AIR pump does not turn ON, the pump may have been damaged by continuous operation. Test or replace the AIR pump. Then, 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 all circuits and AIR pump relay test normal, replace the engine control module (ECM). |
| ⇒ | If the AIR pump does not turn OFF, test the AIR pump voltage supply circuit for a short to voltage. If the circuits test normal, test the AIR pump relay control circuit for a short to ground. If all circuit test normal, test the AIR pump relay. If all circuits and the AIR pump relay test normal, replace the ECM. |
Component Testing
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 control module replacement, setup, and programming |
Repair Verification
With the ignition ON and the engine OFF, observe that the AIR pump is not operating.
