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2005 chevy trailblazer_ls
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Discussion Starter #1
Last year around March, my check engine light came on with this code. Had everything checked out, replaced the Air Pump and the relay and the light went off. Stayed off until this March. Doing some research, I found that most likely I should have replaced the Air Pump Valve as well. I have changed all three this time (valve, pump and relay) and reset the light. After 20 miles the light has come back on. What else could be causing this issue? I have read that it could be the oxygen sensor but I don't want to replace that if it isn't going to correct the problem. I need to get this TB inspected by the end of the month for my new tags. Any help would be greatly appreciated.:bonk::bonk::bonk:
 

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2005 gmc envoy_sle_xl
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Last year around March, my check engine light came on with this code. Had everything checked out, replaced the Air Pump and the relay and the light went off. Stayed off until this March. Doing some research, I found that most likely I should have replaced the Air Pump Valve as well. I have changed all three this time (valve, pump and relay) and reset the light. After 20 miles the light has come back on. What else could be causing this issue? I have read that it could be the oxygen sensor but I don't want to replace that if it isn't going to correct the problem. I need to get this TB inspected by the end of the month for my new tags. Any help would be greatly appreciated.:bonk::bonk::bonk:
I have heard this could be a water issue but it ain't winter in your neck of the woods.
 

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It could be the air pump again...I *just* had mine replaced again...SES light came back on 14 mos after replacement. I figured it couldnt be the air pump again, so I replaced the check valve, relay and 02 senor. Nope,waste of time, water was in the pump and even though I could hear the pump whining at start-up...it was toast.

14 months on a GM part....one winter.
 

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Air Pump

Water ( condensation ) fills that pump and causes it to die. Its a bad design. Some people drill a small hole in the hose so water can drip out. If you have water the pump will freeze in the winter.. Im frustrated with mine.
 

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Discussion Starter #5
In the last week I have changed the Air Pump, Air Pump Relay and the check valve. I had the light reset and after 30 miles it came back on. After doing some research I found that the Oxygen Sensor can also cause this P0410 code. I replaced that today and reset the light. Hopefully this will work, but if not, are there any other parts besides those I have already changed that could be causing this?
 

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2004 gmc
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...are there any other parts besides those I have already changed that could be causing this?
Are you troubleshooting it, or shotgunning? There are two relays and two fuses and some wiring and a couple of grounds involved. Did you find the master P0410 troubleshooting thread? In it, it's discussed to listen for the first 30 seconds of a cold start with the two hoses disconnected at the check valve. The hose from the blower should blow hard, and the check valve should let exhaust noises out before it closes down. If those work, then suspect the O2 sensor for being sluggish, especially if you didn't change it at 100K miles with your plugs (and you're over 100K miles). You can also look at O2 sensor data in real time with a suitable scan tool and see if it's wiggling as required at more than one Hz.

If the pump is intermittent or the check valve is flaky, check the electrical wiring and the relays. Do you have a meter?
 

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2005 Chevrolet TrailBlazer - 4WD | Envoy, Rainier, TrailBlazer, Ascender VIN S/T Service Manual | Document ID: 1698119
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#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)




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

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

Recommendation/Instructions:
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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Discussion Starter #8
Ok so I changed the O2 sensor and reset the light...after 25 miles it was back on. Hooked the Scan Tool back up and this time it's giving me more detailed information along with the P0410 code. It is showing the issue to be the catalytic converter. Looking to get this changed this week and I will update with any issues or if there are further problems after changing this.
 

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Color me doubtful. Still recommend the functional test to make sure the blower and check valve work, especially after the sensor change. Don't see any relationship with a bad cat, unless excessive backpressure is affecting the upstream O2 sensor, in which case you would have many other performance concerns as well.
 

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Discussion Starter #10
The functional test showed the blower and check valve are working properly which is a good thing since I just replaced them in the last month. Everything is still pointing to the Cat. What performance problems should I be experiencing? Other than bad gas mileage (12-14), everything runs and seems fine.
 

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As I said, I have the shop manual, and know of no troubleshooting flowchart for the SAIS that involves the cat. What exactly is your scan tool telling you - codewise?
 

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Discussion Starter #12
Sorry it has been so long - but the code that I am getting is P0410. It actually shows two codes but they are both P0410. I have the CAT and EVA indicators flashing that the issue is with them. I have an appointment with a mechanic on Monday (a couple of days away) to see what he can find. I have already changed the O2 sensor, Air Check Valve, Air Pump, and Air Pump Relay. I'm really dumb when it comes to vehicles so any additional help you can offer would be greatly appreciated so I can make sure I'm not getting shafted on Monday.
 

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2004 gmc envoy_sle
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Results

Sorry it has been so long - but the code that I am getting is P0410. It actually shows two codes but they are both P0410. I have the CAT and EVA indicators flashing that the issue is with them. I have an appointment with a mechanic on Monday (a couple of days away) to see what he can find. I have already changed the O2 sensor, Air Check Valve, Air Pump, and Air Pump Relay. I'm really dumb when it comes to vehicles so any additional help you can offer would be greatly appreciated so I can make sure I'm not getting shafted on Monday.
Any results from the Cat change out?????
 

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P0410

I tried doing the troubleshooting described on here but I'm not that good with trouble shooting cars. What I did do is disconnect the 2 hoses from the pump underneath the car, and got a big wet surprise. Bad smelling brownish water. Before I did this, I did start the car cold with the hoses from the valve mounted on the side of the engine off. There is like a fluttering sound coming from it and it does push some air out. I then checked the return hose that attaches to the big induction hose that goes to the TB. There was nothing coming or going. That is when I went underneath and disconnected the bottom hoses. They were both filled with water, one more than the other. This morning I went to start the car cold, with both hoses up top disconnected, and heard the same fluttering coming from the valve and air pushing out from the other hose going to the intake. I did disconnect the battery last night to cycle the PCM . I hope I am checking everything ok with the exception of all the electrical troubleshooting. My other concern would be if the check valve is faulty and what does it look like and where its located. If someone can chime in here It would help.:confused:
 

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the valve is the part that you took the hoses off of on the right side of the motor. its only held on by 2 threaded studs with nuts on them. theres a gasket between the two surfaces,as well, if you are planning on replacing. not a hard job.
 
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