P2433

DTC P2433

System Description

The DTC P2433 Secondary Air Injection (AIR) System Pressure Sensor Circuit High Voltage diagnostic detects an out of range sensor signal. 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. The PCM supplies the pressure sensor with a 5-volt reference, an electrical ground, and a signal return circuit that has a 5-volt bias. 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 ignition is ON or the engine is running.
* DTC P2433 runs continuously once the above condition has been met.

Conditions for Setting the DTC

The pressure sensor signal is more than 4.8 volts for at least 0.5 seconds.

Action Taken When the DTC Sets

* The PCM illuminates the malfunction indicator lamp (MIL).
* 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 MIL turns OFF after 3 consecutively passing trips without a fault 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

* An intermittent malfunction may be caused by a fault in an AIR pressure sensor electrical circuits. Inspect the wiring harness and components for an intermittent condition. Refer to Intermittent Conditions (Intermittent Conditions).
* If the DTC cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.
* Operating the vehicle in Check Mode will increase the ability of the powertrain control (PCM) module to detect engine control system malfunctions. Refer to Check Mode in Service Bay Test (Component Tests and General Diagnostics).

Test Description

The numbers below refer to the step numbers on the diagnostic table.
1. 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.
2. This step determines if DTC P2433 is the result of a hard failure or an intermittent condition. Normal pressure sensor input voltage is approximately 1.6 volts with the ignition ON, AIR pump OFF.
5. The pressure sensor signal circuit carries a 5 volt bias that can be measured with the DMM. If the measured voltage is near zero there is an open or a faulty PCM.
7. This step checks for an open in the pressure sensor ground circuit.