GM Service Manual Online
For 1990-2009 cars only

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 provides an overview of each diagnostic category.

DTC Descriptors

DTC P2430 : Secondary Air Injection (AIR) System Pressure Sensor Stuck in Range

DTC P2431 : Secondary Air Injection (AIR) System Pressure Sensor Performance

DTC P2432 : Secondary Air Injection (AIR) System Pressure Sensor Circuit Low Voltage

DTC P2433 : Secondary Air Injection (AIR) System Pressure Sensor Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Pressure Sensor 5-Volt Reference Voltage

P0641, P2432

P2432

P0641, 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

AIR Pressure Sensor

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 powertrain control module (PCM) 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:

  1. DTCs P0411 and P2430 run during Phase 1
  2. DTCs P2430 and P2440 run during Phase 2
  3. 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 15-22 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 PCM 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

P2430

    • DTCs P0412, P0418, P0606, P0641, P0651, P2432, P2433 are not set.
    • The AIR pump is commanded ON.
    • The start-up engine coolant temperature (ECT) is between 5-50°C (41-122°F).
    • The start-up intake air temperature (IAT) is between 5-60°C (41-140°F).
    • DTC P2430 runs continuously when the above conditions are met.

P2431

    • DTCs P0107, P0108, P0412, P0418, P0606, P0641, P0651, P2432, P2433 are not set.
    • The ignition is ON.
    • DTC P2431 runs continuously when the above conditions are met.

P2432 and P2433

    • DTCs P0606, P0641, P0651 are not set.
    • The ignition is ON or the engine is running.
    • DTC P2432 and P2433 run continuously when the above conditions are met.

Conditions for Setting the DTC

P2430

    • The measured AIR pressure change does not meet expected pressure changes during AIR pump phase 1 or phase 2 operation.
    • DTC P2430 sets within 8 seconds when the above condition is met.

P2431

    • The PCM determines that the difference between the AIR pressure sensor and the barometric pressure (BARO) sensor signals is greater than 10 kPa when the AIR pump is commanded OFF.
        OR
    • The PCM determines that the difference between the AIR pressure sensor and the BARO sensor signals is greater than 50 kPa when the AIR pump is commanded ON.

P2432

The pressure sensor signal is less than 0.2 volt for at least 12.5 seconds.

P2433

The pressure sensor signal is equal to or more than 4.75 volts for at least 12.5 seconds.

Action Taken When the DTC Sets

DTCs P2430, P2431, P2432, and P2433 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P2430, P2431, P2432, and P2433 are Type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Powertrain Control Module Connector End Views
    •  Engine Controls Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions
    •  Scan Tool Output Controls

Circuit/System Verification

  1. Ignition ON, engine OFF, verify that the AIR Pressure Sensor parameter is within 3 kPa of the BARO parameter.
  2. If not the specified range, verify that the BARO parameter is correct for your altitude. Refer to Altitude Versus Barometric Pressure. If the BARO parameter is not correct for your altitude, refer to DTC P0106.
  3. Engine running, command the AIR Pump Relay ON while observing the AIR Pressure Sensor parameter. The reading should be 15-20 kPa above the BARO reading.
  4. Engine running, command the AIR System ON while observing the AIR Pressure Sensor parameter. The reading should be 7-10 kPa above BARO.
  5. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Ignition OFF, disconnect the harness connector at the AIR solenoid valve.
  2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 1 and ground.
  3. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the PCM.
  4. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 and ground.
  5. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PCM.
    If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the PCM.
  6. Verify the scan tool AIR Pressure Sensor parameter is less than 0.5 volt.
  7. If greater than the specified range, test the signal circuit terminal 2 for a short to voltage. If the circuit tests normal, replace the PCM.
  8. Install a 3A fused jumper wire between the signal circuit terminal 2 and the 5-volt reference circuit terminal 3. Verify the scan tool AIR Pressure Sensor parameter is greater than 4.9 volts.
  9. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PCM.
  10. If all circuits test normal, replace the AIR solenoid valve assembly.

Repair Instructions

    •  Secondary Air Injection Pump Replacement
    •  Secondary Air Injection Shut-Off Valve Outlet Pipe/Hose Replacement
    •  Secondary Air Injection Shutoff Valve Replacement
    •  Powertrain Control Module Replacement for PCM replacement and programming

Repair Verification

  1. Install any components or connectors that have been removed or replaced during diagnosis.
  2. Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.
  3. Clear the DTCs.
  4. Turn OFF the ignition for 90 seconds.
  5. Ignition ON, observe that the AIR Pressure Sensor parameter is within 3 kPa of the BARO parameter.
  6. Engine running, command the AIR Solenoid Relay ON with a scan tool. Observe the scan tool AIR Pressure Sensor parameter equals 8-10 kPa above BARO.
  7. Engine running, command the AIR Pump Relay ON with a scan tool. Observe the scan tool AIR Pressure sensor parameter equals 15-22 kPa above BARO.