System Description
The DTC P2432 Secondary Air Injection (AIR) System Pressure Sensor Circuit Low 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 P2432 runs continuously once the above condition has been met. |
Conditions for Setting the DTC
The pressure sensor signal is less than 0.1 volt 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 . |
| • | 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 . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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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.
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This step determines if DTC P2432 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.
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This step checks for an open in the pressure sensor reference voltage circuit.
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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 a short to ground or a faulty PCM.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | ||||
Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | ||
Is the pressure sensor input circuit voltage within the specified value? | 1.5-1.6 V | Go to Step 3 | Go to Step 4 | |
3 |
Did DTC P2432 set? | -- | Go to Step 4 | Go to Diagnostic Aids |
4 | Was DTC P0122 also set? | -- | Go to Step 9 | Go to Step 5 |
Is the voltage near the specified value? | 5.0 V | Go to Step 6 | Go to Step 8 | |
Measure the voltage of the pressure sensor input circuit with a DMM. Is the voltage near the specified value? | 4.9 V | Go to Step 10 | Go to Step 7 | |
7 |
Was a repair necessary? | -- | Go to Step 12 | Go to Step 11 |
8 | Repair the open in the 5-volt reference sensor circuit between the pressure sensor and SP108. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 12 | -- |
9 | Repair the open in the 5-volt reference sensor circuit between the PCM and SP108. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 12 | -- |
10 | Replace the AIR pressure sensor. Refer to Secondary Air Injection Pressure Sensor Replacement . Is the action complete? | -- | Go to Step 12 | -- |
11 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 12 | -- |
12 |
Does the DTC run and pass? | -- | Go to Step 13 | Go to Step 2 |
13 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
