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Billy, Chevrolet tecnician
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Experience:  Over 25 years experience,GM grand master for 8 years,certified smog and government safety inspector
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I have a 2004 Envoy That is giving me a PO410 Code (Secondary

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I have a 2004 Envoy That is giving me a PO410 Code (Secondary Air Injection System). I have reset the code, but it keeps coming on. What would be causing this problem, and do I need to replace something on the vehicle, or could it just be a bad sensor? What effect does ignoring the code have on the engines performance.
hello and welcome to just answer.

There is an extremely lengthy diagnostic chart that I can provide for you, however unless you are familiar with todays electronics and poses a TECH-2 scan tool it would not be much help for you.
There is also a bulletin that I will provide, it states that an oxygen sensor could cause this problem. I would speculate that if the air pump operates correctly replace the o2 sensor and retest the system.

If you feel my answer was helpful, please click the ACCEPT button. Feedback & Bonuses are always welcome.
Best regards,

#PIP3530: Repeat SES Light Due to a P0410 DTC - Possible O2 Sensor - keywords AIR CEL injection MIL oxygen pump secondary - (Aug 24, 2005)
Subject:Repeat SES Light due to a P0410 DTC - Possible O2 Sensor
Models:2004-2005 Buick Rainier
2004-2005 Chevrolet TrailBlazer
2004-2005 GMC Envoy
2004 Oldsmobile Bravada
2005 Saab 9-7x
with 4.2L Engine (VIN S - RPO LL8)

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.


Currently, the SI diagnostics do not mention the position 1 O2 sensor as a potential cause of a P0410 DTC.


If the SI diagnostics do not isolate the cause of a P0410 DTC, there is no sign of dirt or water in the AIR pump or relay, and proper AIR check valve operation is noted, replace the position 1 O2 sensor.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

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Customer: replied 7 years ago.
Where would I find the Air pump, check valve and relay so I can check them (is this a fairly easy thing to check or complex)? I had a dirty Air filter, could it have clogged the pump, or is on a different system? Also, is it possible to get an aftermarket O2 sensor on this vehicle or do I have to go to GM??
You can get an aftermarket sensor if you like to although the oem one is better quality.
The air filter is not related to the problem with the air pump, they are on a different air intake system.
The pump is located on the frame rail under the vehicle.
Object Number:(NNN) NNN-NNNN Size: SH
The injection solenoid is above the exhaust manifold under the air intake assembly.
Object Number:(NNN) NNN-NNNN Size: SH
if you need more information let me know. I will send you the description of operation as well.
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Secondary Air Injection (AIR) System Description

The Secondary Air Injection (AIR) System reduces exhaust emissions following initial engine start up. This occurs when the engine Start-up coolant temperature is between 3-50°C (37-122°F) and the intake air temperature (IAT) is more than 1°C (32°F). The AIR pump will operate until Closed Loop operation is achieved.

The powertrain control module (PCM) activates the AIR system by suppling a ground to the AIR pump relay and AIR solenoid relay simultaneously. This action closes the internal contacts of the AIR pump relay, energizing the AIR pump and also closes the internal contacts of the AIR solenoid relay, energizing the AIR solenoid, opening the shut-off valve. The AIR pump forces pressurized fresh air into the pipes/hoses and past the check valve into the exhaust manifold, accelerating catalyst operation. When the AIR system is inactive, the AIR shut-off valve prevents airflow in either direction.

The AIR system includes the following components:

The AIR pump
The AIR pump supplies pressurized, filtered air to the exhaust stream. The AIR pump is a turbine type pump which is permanently lubricated ad requires no periodic maintenance. The AIR pump for the 4.2 liter engine will draw a steady 35-40 amps under normal operation. The AIR pump has an internal circuit breaker to protect the pump from overheating. The circuit breaker is an integral part of the AIR pump.
The AIR shut-off valve
The AIR shut-off valve has an electronic solenoid mounted on the valve. The resistance of the solenoid is 4-7 ohms and the current draw is 2-3.5 amps. The solenoid opens the shut-off valve when battery voltage is applied to the valve. Once opened, pressurized air from the AIR pump flows past the check valve and is directed into the bank 1 exhaust manifold through an outlet pipe. The shut-off valve prevents fresh air from being drawn into the exhaust manifold by providing a positive seal when the AIR system is inactive. The solenoid, valve, and outlet pipe are serviced as an assembly.
Important: An audible exhaust noise may be heard at the inlet of the shut-off valve, when the shut-off valve is opened and the AIR pump outlet hose is removed from the shut-off valve.
The AIR pump relay
The AIR pump relay supplies high current and battery voltage to the AIR pump. The resistance of the AIR pump relay coil is 55- 68 ohms.
The AIR solenoid relay
The AIR solenoid relay supplies high current and battery voltage to the AIR solenoid that is an integral part of the shut-off valve. The PCM commands the AIR solenoid relay ON by suppling a ground on the control circuit of the relay. The resistance of the AIR pump relay coil is 80-90 ohms.
The pipes and hoses
The pipes/hoses carry the air from the AIR pump past the AIR shut-off valve, and into the exhaust manifold. A pipe connects the shut-off valve to the exhaust manifold. The AIR System also utilizes a hose to carry the filtered air to the inlet of the AIR pump.
The inlet filter
The filter utilizes the air filter for the engine. This system draws filtered air directly from the air cleaner assembly.

Results of Incorrect Operation

The PCM can detect an AIR System airflow fault by monitoring the heated oxygen sensor (HO2S) bank 1 sensor 1 during normal engine operation. This is an active test. The PCM will command the AIR system ON during Closed Loop operation to perform this test. The active test will pass or fail based on the response from the HO2S 1. The active test consists of three tests run at 3-second intervals. A decreasing HO2S voltage parameter response indicates that the secondary AIR system is functioning properly. If the PCM does not detect a decreasing response from the HO2S 1, DTC P0410 will set.

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