p2432

[Jason Bland]

Trailblazer is throwing this code. No performance issues. enginecodes.com lists possible causes as: faulty AIR pressure sensor; AIR pressure sensor harness is opened or shorted; AIR pressure sensor circuit poor electrical connection.

In your experience, where would the best bet be to look first?

 

[AtlWrk]

There is an air pressure sensor built into the SAIS valve that's mounted just above the exhaust manifold. P2432 points to either a faulty sensor or a problem with the wiring the connects it to the PCM.

I've seen a number of flakey electrical issues pop up lately because of the cold weather that corrected themselves. First thing I'd do is remove the electrical connector and inspect it for corrosion, broken wires, etc. and reinstall. Sometimes removing and reseating the connector is enough to clean it up and restore contact.

Are you familiar with using a voltmeter? If you remove the electrical connector there will be five pins. Pins 1 (dark blue wire) and 3 (brown wire) should show 5 volts between them. EDIT: with the ignition ON, engine OFF.

 

[Jason Bland]

Thanks. I hate unplugging some of the wiring connections, since they can be so stubborn. This is one of them.

 

[Jason Bland]

I messed with the connection a bit yesterday and went back in the house after I couldn't get it loose with bare hands. Tonight I went back out and gave the edge a tap with hammer and screwdriver and it popped loose. There is a ton of moisture in there. I'll dry it off, clean it, test it and plug it back in, I guess.

 

[Jason Bland]

I dried everything with a hair dryer and checked the voltage between the dark blue and brown wires. It was 4.95V. I reconnected, cleared the code and cold started the truck, which led it to throw the P2432 again. I warmed it up and cleared the code once more but I assume it will throw it again tomorrow morning. Do I get a new valve/solenoid/sensor assembly now?

How would so much moisture get in there? I purchased this truck 5 days ago from a Chevy dealer......2 weeks ago I had a 2004 trailblazer but my wife totaled it. I felt lucky to find this truck.....it's loaded and in unbelievable condition inside and out with 68,000 miles on it. It was throwing the code when I looked at it (I had my scan tool) and that just seemed like a positive bargaining chip in my favor.

 

[AtlWrk]

I'm assuming you bought the truck As-Is? I'm surprised the dealer wouldn't throw a new valve at it for $100 to have no codes on a truck they're trying to sell. No other codes I assume? Something's up there...but anyway.

It is odd to have moisture in that connector Might be an internal leak from a failed sensor or the seals on the connector itself. With all that moisture did the terminals looks corroded? Might try pulling the connector and reseating a few times to clean them up.

New valves can be had for ~$100 online and they're dead simple to swap. The only other possibility is a problem with the yellow signal wire, but that's trickier to diagnose. You need to measure the yellow wire relative to ground with everything connected, while the SAIS is active (you only have about 30 seconds at a cold start).

This is just my opinion, and others may chime in, but at this point I would go ahead and swap the valve.

 

[Jason Bland]

Yes, I thought it was funny that they didn't fix it first, but they were asking $600 over NADA clean retail price. When we talked business, he came down, unsolicited, to clean retail right away as the price for the vehicle as-is, or he said they could fix it at the original ($600 over clean retail) price (Jedi mind trick?). When I pointed out that the as-is price was clean retail he seemed kind of annoyed and said he didn't look at that. Anyway I asked for another $300, got it, and was happy to find such a nice truck. There is a three month dealer warranty on catstrophic failure, and a report we got from OnStar (came with 3 free months) said we had an active warranty of 10 years/100,000 miles, which I'm hoping wasn't just for the original owner.

I did remove/reseat the connector several times last night before dropping the hood. I could not see corrosion. As far as the moisture goes, could some mutt have detailed the truck and used high pressure water in the engine compartment?

I'm going to order the Delco valve from rockauto. It looks like I have to order the gasket separately, too.

I know I would have to backprobe and only have a short time on a cold start for the other test you mentioned. Would I need 2 meters? What would I be looking for? I'm very weak on electrical stuff. Thanks.

 

[BlazingTrails]

I have a good used one if you want it? $45 shipped?

 

[Jason Bland]

I don't know who may have read it, but I have to apologize for repeating something that my wife said (we should all know better) about a 10 year/100,000 mile warranty on my 07 Tblazer. I looked into it, and it's actually a special coverage on the fuel sending unit, which is known to fail. My coverage expires at 120,019 miles or in October of 2016. It is Special Coverage 10054. If your fuel gauge stops working, it may be the sending unit, and it may be covered.....at least partially. Just go to the Chevy owner center online with your VIN# to see.

 

[nagyiii]

I don't know who may have read it, but I have to apologize for repeating something that my wife said (we should all know better) about a 10 year/100,000 mile warranty on my 07 Tblazer. I looked into it, and it's actually a special coverage on the fuel sending unit, which is known to fail. My coverage expires at 120,019 miles or in October of 2016. It is Special Coverage 10054. If your fuel gauge stops working, it may be the sending unit, and it may be covered.....at least partially. Just go to the Chevy owner center online with your VIN# to see.




Once GM sent out that letter saying they were finally covering that replacement at 100%, I got mine replaced. My fuel gauge quit working 4 yrs ago, right when I hit 100K. Last year it started leaking fuel from the sending unit one day after I got that letter. Took it to my local GM dealer, they wanted $1200 to do it. Called GM and asked if I had to take it to a GM dealer, they told me no. Took it to my normal repair shop, they did it for $325, sent the receipts to GM, and they sent me a check 10 days later. GM figures that since most of these vehicles are over the year or mileage threshold, they won't be paying out too many for repair.... crooked!! Should have been a recall all along!!