P2440
DTC P2440
Diagnostic Instructions
* Perform The Diagnostic System Check - Vehicle Initial Inspection and Diagnostic Overview
* Strategy Based Diagnosis
* Diagnostic Procedure Instructions
DTC Descriptor
DTC P2440
- Secondary Air Injection (AIR) System Shut-Off Valve Stuck Open
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:
* 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-P0208, P0300, P0351-P0358, P0411, P0412, P0418, P0420, P0606, P0641, P0651, P2430, P2431, P2432, P2433, 2444 are not set.
* The system voltage is 9-18 volts.
* The BARO is more than 70 kPa.
* The MAF sensor is less than 33 g/s.
* DTC P2440 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 AIR system does not meet expected pressure conditions.
* DTC P2440 sets with in 8 seconds when the above conditions are met.
Action Taken When the DTC Sets
DTC P2440 is a Type B DTC
Conditions for Clearing the MIL/DTC
DTC P2440 is a Type B DTC
Circuit/System Verification
1. If any other Secondary Air Injection System Pressure Sensor Circuit DTCs are set then perform those diagnostics first.
2. Ignition ON, enable and disable the AIR solenoid relay and observe that the solenoid valve operates.
3. Inspect the AIR hoses/pipes between the pump and the shut-off valve for leaks.
4. Engine running, enable the AIR pump relay and observe that the AIR Pressure Sensor parameter increases to approximately 10-20 kPa above BARO.
Circuit/System Testing
1. Disconnect the AIR solenoid valve.
2. Ignition ON, connect a test lamp between the AIR solenoid voltage supply terminal 6 and the solenoid ground circuit terminal 4, the test lamp should not illuminate.
• If the test lamp illuminates, test the AIR solenoid supply voltage circuit for a short to voltage. If the circuit tests normal, test or replace the AIR solenoid relay.
3. Inspect the AIR pump inlet and outlet hoses/pipes for leaks or restrictions.
4. Inspect the AIR solenoid valve for leaks.
Component Testing
AIR Solenoid Static Test
Measure the AIR solenoid for a resistance of 4.8-6.8 ohms across the B+ terminal 6 and the ground terminal 4 at the AIR check valve at an ambient temperature of approximately 20°C (68°F).
If the resistance is not within range, replace the AIR check valve assembly.
AIR Solenoid Test
Install a 10-amp fused Jumper wire between the battery voltage supply terminal and 12 volts. Install a Jumper wire between ground terminal at the solenoid valve and ground. The AIR solenoid valve should open when the Jumper is connected to ground and close when the Jumper is removed from ground.
If the solenoid valve does not perform as specified, replace the check valve and assembly.
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
* Secondary Air Injection Check Valve Replacement
* Control Module References for engine control module (ECM) replacement and programming Programming and Relearning
Repair Verification
1. Ignition ON, enable and disable the AIR solenoid relay and observe that the check valve operates.
2. Inspect the AIR hoses/pipes between the pump and the shut-off valve for leaks.
3. Engine running, enable the AIR pump relay and observe that the AIR Pressure Sensor parameter increases to approximately 10-20 kPa above BARO.