Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Pressure Sensor 5-Volt Reference Voltage | P0335, P0651, P2135, P2432, | P2432 | P2431, P0651 | P2430, P2431 |
Pressure Sensor Signal | P2432 | P2432 | P2433 | P2430, P2431 |
Pressure Sensor Low Reference | -- | P2433 | -- | P0411, P2431 |
Pump Supply | P0411 | P0411 | P0411, P2444 | -- |
Pump Ground | -- | P0411 | -- | -- |
Solenoid Supply | P0411 | P0411, P0412 | P2440 | -- |
Solenoid Ground | -- | P0411 | -- | -- |
Pump Relay Supply | P0102, P0412, P0418, | P0418 | P0690 | -- |
Pump Relay Control | P0418 | P0418 | P0411, P0418, P0690, P2431 | -- |
Pump Relay Switch Supply | P0411 | P0411 | -- | -- |
Solenoid Relay Supply | P0412 | P0411, P0412 | P0690 | -- |
Solenoid Relay Control | P0412 | P0411 P0412 | P0411, P0412, P0690 | -- |
Solenoid Relay Switch Supply | P0411 | P0411, P0412 | -- | -- |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Key ON, Engine OFF Normal Operation Range: BARO Refer to Altitude Versus Barometric Pressure | |||
5-Volt Reference Voltage | 40 kPa | 40 kPa | 111 kPa |
Pressure Sensor Signal | 40 kPa | 40 kPa | 145 kPa |
Low Reference | BARO | 145-150 kPa | -- |
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. The secondary AIR injection pump, provides filtered air on demand to the AIR check valve assembly. The AIR check valve assembly controls the flow of air from the AIR pump to the exhaust manifold. The AIR CNTRL relay supplies the current needed to operate the AIR solenoid that is integral to the check valve assembly. A pressure sensor, also integral to the check valve assembly, 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 signal circuit provides the control module with a voltage relative to internal AIR pressure changes.
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 10-20 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 solenoid, pressure sensor, related wiring, and the exhaust check valve. The pressure sensor can also detect leaks and restrictions in the secondary AIR system plumbing. Refer to Secondary Air Injection System Description for further information.
• | DTCs P0412, P0418, P0606, P0641, P0651, P2432, P2433 are not set. |
• | The AIR pump is commanded ON. |
• | DTC P2430 runs once per trip where AIR pump operation is required at startup. |
The ECM determines that the pressure sensor is less than a calibrated value.
• | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
• | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
• | The control module turns OFF the malfunction indicator lamp (MIL) at the beginning of the fourth ignition cycle, after 3 ignition cycles that the diagnostic runs and does not fail. |
• | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
• | A history DTC and related Freeze Frame data clears after 40 warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
• | Clear the MIL and the DTC with a scan tool. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
⇒ | If less than the specified range, verify that the AIR pump is activating. |
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | 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 ECM. |
⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | 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 ECM. |
⇒ | If not within the specified range, continue with this procedure. |
⇒ | If within the specified range, the AIR pump inlet hoses/pipes are restricted. Remove the restriction, or replace the hose/pipe. |
⇒ | If not within the specified range, continue with this procedure. |
⇒ | If within the specified range, the AIR pump outlet hoses/pipes are restricted or leaking. Remove the restriction or replace the hose/pipe. |
⇒ | If less than the specified range, replace the AIR pump. |
⇒ | If more than the specified range, continue with this procedure. |
⇒ | If more than the specified range, replace the AIR solenoid valve. |
⇒ | If within the specified range, the AIR solenoid valve outlet pipe or the exhaust system is restricted. Remove the restriction or replace the appropriate component. |
Apply appropriately fused battery voltage and ground to the solenoid and verify that the valve opens and closes completely as voltage is applied to and removed from the solenoid. Observe that the valve is not obstructed or leaking.
⇒ | If the valve operates incorrectly, leaks, or is obstructed, remove the obstruction or replace the valve. |
• | Control Module References for engine control module (ECM) replacement, setup and programming |