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2007 Armada LE
1 Posts
Discussion Starter · #1 ·
Good afternoon Armada Fans!

First off I'd like to thank all of you that i've obtained information and assistance from, here in this forum! I'm an IT person and before I got this vehicle (now at 223k miles), I had what you might call a mechanical knowledge gap, and over the last five years I've embraced the wrench life - I tend to keep vehicles a long time so I've learned to DIY whatever I can, especially since being in my industry and knowing how much per hour technical stuff runs. From this forum and its generous members I've been able to replace my bad air shocks with some Bilsteins, springs, my front struts, fixed my AC system (its as good as its gonna get at this point), replaced my clock spring, charcoal canister solenoid, all the hydraulic pistons for the gate and hood, and obtained the Nissian Diag Software and interfaced my tablet with is so I can really view some of the advanced ECU/ECM diagnostics (and reset that darn slip sensor), so if ever any of you are in the OKC I'll buy ya a beer or wrassle up some BBQ with ya!

Now we get into scandalous territory. Started getting p420 and p4xx codes, stalling, stinky exhaust, and a tinking sound in my front exhaust when idling.

Took off my rear exhaust pipe, parts of the catalytic materiel were chunked out and vibrating, and all 4 cats were almost totally jammed. Faced with a $3000 replacement cost, I decided to bore them all the way out (made sure I got all the materiel out and disposed of it properly, I had access to a HAZMAT collection place) and replaced the rear o2 sensor with a dummy plug that has a small cat in it. Haven't replaced the front sensors yet, but my scanner shows they are getting proper voltage. After this, it sounded a lot cooler and all the other problems stopped - for awhile.

Then I started getting a p2003 code. Research tells me that this is a Diesel Particulate Filter code, but of course this is a gas engine. Cleaned my PCV valves, checked for exhaust leaks, and was going to clean/replace the EGR valve but it looks like this 5.3 engine doesn't have one. Any search for a p2003 code leads me to advice or solutions for different engines or vehicles I don't have. I figures at some point I'd install new cats myself, but I'm curious why this code that shouldn't exist is showing for this vehicle and wanted to ask the experts here for some guidance. I'd like to keep this vehicle until I need to get a new timing chain/pump or I can be buried in it.

6,652 Posts
im not a mechanic but i will try to help.

P 2 0 0 3

OBD-II Diagnostic Powertrain Trouble Code For Engine

Fuel And Air Metering (Injector Circuit Malfunctions Only)

Ambient Air Temperature Sensor Circuit Low

Cold Start Injector 1 Malfunction

Exhaust Gas Recirculation Sensor B Circuit High

this is a generic code which obviously differs from car to car. it seems to boil down to an emissions issue, and since you removed your cats and altered some sensors, this may be the closest dtc the ECM can give.

you may not have a diesel engine but you do have cats, and along with the o2 sensors, they tell the ECM what the particulate count is in the exhaust and adjust voltages, etc., as needed to keep emissions at bay. since you removed/modified some of these items, the ECM is not getting the data it expects, causing this potential DTC.

some things to check:
1- plugs and coil packs
2. compression
3. wiring to and from the 02 sensors

are you driving the car a lot? getting the engine hot will burn off the contaminants so driving it on the road for half an hour or so may burn this off and improve things.

i would imagine your mpg is suffering as well yes? what about torque and overall performance, has it slacked? look up the "ecm reset" on this forum in case you dont know and reset the ecm.
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