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This is a topic that reappears now and then,
especially from new people. So here it is again.
The under-hood light is on the same circuit as the air pump. It's a small
yellow-colored fuse (20 A if memory serves).
When the under-hood light fails to come on when the hood is open, it's probably
because of a short in the air pump (an electric motor) rather than a bad bulb in the
under-hood lamp box. The short causes the little yellow fuse to blow.
If you replace the fuse, it will probably blow again because the problem is in
the air pump.
The air pump only comes on in two (2) circumstances:
1. At startup for approx 4 minutes, to help blow air into the exhaust
manifolds to warm up the cats faster. This reduces the elevated levels of
unburned hydrocarbons (HCs) that occur when the cats are too cold to do
anything. After 4 minutes, the air pump shuts off because the cats are
warm enough.
2. At WOT, the air pump goes on to (again) reduce unburned HCs because the
fuel:air mixture is deliberately rich at WOT.
I'm attaching my air pump file. It has some good info,
particularly the item about taking yours apart and cleaning it. This is a
worthwhile thing to try before you shell out $150+ to get a new one.
Don't ask me any further questions about this; I know only what I've
read/remembered and saved in the below file. FYI.
Ken Rolt
From: Basim Jaber
Date: Wed, 20 Aug 1997 14:25:05 -0700
Subject: AIR pump TSB and other tech info....
To All,
I had my car in this morning for a new AIR pump check valve (p/n 12552787) which
was sticking and causing a "check engine" light to come on. The technician got to talking and he provided me with some real neat
info.
First topic: Check Engine light.
I was informed that when this light comes on (obviously because the PCM set a
DTC error from a sensor reading), it will stay on even if the problem fixes
itself (i.e. my check valve unsticking intermittently). After THREE
successful error-free starts of the car, the LIGHT WILL GO OFF. The DTC is
still stored in the PCM's memory, though. ALSO, after 40 successful
error-free starts, the PCM will CLEAR ALL DTC's. So get your car scanned
ASAP when you get that light! (even if it goes away!)
From: Basim
LASTLY: AIR pump TSB!!!
TSB # 77-65-13 (I don't know all that much about it, only what
the tech told me after it showing up on a TSB search when he ran my VIN in the
computer and TSB database)
Apparently this TSB is for MOISTURE in the vaccuum hoses and AIR pump. It
calls for replacing the ENTIRE AIR pump assembly and other items.
This is what was ordered (not sure of quantities):
#12554580 AIR pump
#22048212 Check Valve (possibly better than the one which was replaced
this morning!...go figure!)
#12558522 AIR kit (probably consists of hoses, plastic clamps, etc)
I take the car back next week when the parts are in. Now is that good
service or what?
Basim Jaber, NAISSO #1859
ROD - Region Of Doom (NAISSO - WEST)
From: Basim Jaber
Date: Mon, 22 Sep 1997 12:04:21 -0700
Subject: Frustration at it's finest.
As for the AIR pump. I am STILL waiting for the last of the parts in the
AIR pump TSB (TSB # 77-65-13) to arrive. The "AIR kit" (p/n
12558522 -probably consisting of vacuum hoses and clamps, etc) is still on
backorder from the OEM (not GM) manufacturer and it's really frustrating me.
The AIR pump has been coming on even when the car has been running for long
periods of time. I can hear it come on occasionally for a few seconds (as
if it were trying to shut the check valve). I am fearing that the check
valve is stuck open and the exhaust is cycling through the manifold and back
through the AIR pump and ultimately back through the check valve and into the
intake (where it then can go straight to the throttle body!) Yikes!
Is this assumption viable? If someone knows anything about this, please
reply.
Basim Jaber
p.s. I plan on doing the throttle body bypass also when I do the install.
After all, it doesn't get THAT cold here where I live.
--
I am employing the help of anyone out there who can seriously help me with a
problem regarding my AIR pump. My dealer has ordered the three parts which comprise the AIR pump TSB (#77-65-13) and two of them have arrived:
#12554580 AIR Pump
#22048212 Chk valve
#12558522 AIR kit <----nationwide backorder for ONE MONTH
now.
I have been bumped up to HIGHTEST priority nationwide on this backorder as the
part (kit) has been exhausted and GM has not had any committed vendor to make
this non-GM OEM part (kit). They have searched EVERY dealer nationwide and
found nothing!
Is there anyone else out there waiting for this? Can anyone help me?
I have been staring at my "Check Engine" light for ONE MONTH now.
When I went to the high altitude of Lake Tahoe, the light went off mysteriously
until I got back home at the low altitude (sea level). The AIR pump
solenoid check valve has ALREADY been replaced once (as per DTC
P0410...intermittent AIR pump solenoid check valve sticking), but that didn't
fix it. It's still sticking (I think) as the light came back on the very
same day the check valve was replaced.
The TSB is supposed to me a "modified" AIR pump system to eliminate
"moisture" from forming in the AIR system. I assume it involves
a different routing system. The light came on about three weeks
after I installed the SLP cold air intake and noticed the problem of one of the
filters being susceptible to water entering it through the space between the
hood and fender.
This issue really isn't all that urgent as the AIR pump is only an EPA smog
control device and shouldn't affect engine. But I am thinking that if the
check valve is stuck OPEN, the there is a possibility that exhaust is backing up
through the system and entering the intake at the point where the AIR pump pulls
the air from the intake (air box on stock car). Is my assumption valid?
Basim Jaber, NAISSO #1859
From: Basim Jaber
Date: Tue, 4 Nov 1997 13:19:10 -0800
Subject: AIR pump TSB...DONE
The AIR Pump TSB # is 77-65-13
I found the original diagnosis record at home.
This morning at Raines Chevrolet in Sunnyvale, CA, I had the AIR pump TSB
performed. I can't recall the bulletin number for this TSB but it involves
these three GM p/n's:
#12554580 AIR Pump
#22048212 AIR Valve Assy (QYT 2 needed)
#12558522 Kit
The #12558522 kit comes with instructions which is GM p/n #12558523. This
is a whopping NINE (9) page instruction sheet complete with diagrams.
There are several parts that are replaced on this TSB. Aside from
the AIR pump and AIR check valves (those big black things that lead into the
exhaust manifolds/headers), a new beefy check valve solenoid (#1997260) and one
other new EGR solenoid are used. It also comes with new vacuum tubing and
other miscellaneous parts.
Some of the parts which came with the kit include:
#1997260 (solenoid)...7-digit#
#12558527 (vacuum line)
#12558524 (shut-off valve)
#12558526 (hose)
#12167647 (wire harness)
#12064959 (cap/connector)
#14057004 (hex washer nut)
#12558528 (EGR vacuum line assy)
I got these part numers from the instruction sheet that I got to keep.
Basically, the kit comes with a LOT of goodies. This kit/TSB is a MUST for
cars that have constant DTC/MIL problems with the AIR pump (DTC's P0410 and
P0416) due to moisture in the AIR/EGR system. The mechanic informed me
that my car was his THIRD TSB done in two weeks. The prior two were
Mountain View Police 9C1's that kept throwing the same DTC errors. I
stared at my SES light long enough. Now it's finally GONE! Thank
God!
This new AIR pump system is NICE!! I can barely hear it running! No
annoying whistling at startup. The TSB fixes a problem of MOISTURE
entering the AIR pump and causing it to fail (or not work efficeintly).
The kit/TSB is the same for all Impala models, but the instructions are slightly
different for the 96 (there's one or two parts that are discarded whereas the 94/95 don't have them to begin with). I
recommendthat you take your cars to the dealer and have them scanned for the two aforementioned DTC errors. This TSB is relatively new and your
dealer might not yet know anything of it. Have them run a check and take a
look at it on their TSB database. Total labor time was about 1.5 hours to
perform the TSB. The tech even cleaned off my greasy steering box and it
looks immacculate now.
Basim Jaber, NAISSO #1859
From: "Dr. & Mrs. Gary D. Folske"
Date: Sat, 17 Jan 1998 14:53:03 -0600
Subject: A.I.R. pump
Had the CHECK ENGINE light come on last week and headed to my friendly
"Chivy" dealer. He told me the fuse was blown for the A.I.R.
pump, Yes, I said, that's why the under hood light doesn't work. He looked at me
kind of funny!
He offered to replace the fuse. I said... obviously something made it
blow... replacing the fuse is a bandaged, not a fix. He said OK I'll put
on a new pump. He went to his computer and looked up the code and other info.
He said he had the A.I.R, pump in stock, but, would have to order the kit. I
asked what kit, and he told me that apparently GM has had a lot of trouble with
the A.I.R. pump getting water in them and blowing so they came up with a kit
consisting of two check valves to prevent reoccurrence. They installed the
pump and kit, warranty of course.
Parts listed were:
1 each 12558522 valve kit 3.670 ....warranty
2 each 22048212 valve ASM 3.670 ....warranty
Gary 1996 DCM 1997 IMPALA AR
From: Basim Jaber
Date: Sat, 17 Jan 1998 20:11:09 -0800
Subject: RE: A.I.R. pump
Gary D. Folske wrote:
>> Had the CHECK ENGINE light come on last week and ............
had the A.I.R, pump in stock, but, would have to order the kit. I asked what
kit, and he told me that apparently GM has had a lot of trouble with the A.I.R.
pump getting water in them and blowing so they came up with a kit consisting of
two check valves to prevent reoccurrence. <<
This is TSB # 77-65-13 which replaces the AIR pump, solenoid check valves, new
routing for AIR system, new EGR check valve solenoid, and heavier duty fuse and
vacuum system for AIR system.
Anyone with DTC (error codes) P0410 and/or P1415 can get this TSB performed at
any Chevrolet dealer. If the car is still out of warranty, you still have
a good chance of getting this done as this TSB is real recent and new.
Basim Jaber, Region of Doom (ROD)
From: "Kelly 'Ghostwheel' Rosato"
Date: Mon, 08 Jun 1998 20:47:14 -0700
Subject: AIR pump fuses.
Yes, the AIR pump is indeed electric. However, I sucessfully deleted the AIR
pump on my '94 last week ('96's will throw a PCM code fit). You can simply unplug it if thats your desire OR you can delete it, the tubing and the
hoses into the manifold and the whole bit if you don't have to worry about the
tree-hugger police in your friendly neighborhood.
For mine I'm going to use the 3 mount poition FORMERLY occupied by my AIR pump
to hold a plate with a MSD coil bolted to it I think. Nice tucked away place if
you ask me and its close to the stock location.
As for the exhaust manifolds, 2 22mm x 1.50 steel oil plugs (available at Pep
Boys) for 2 bux plug up those manifolds no problem.
And then you don't have to worry about our POS AIR pumps blowing out your hood lights. :)
Kelly "Ghostwheel" Rosato
1996 DGGM SS & 1994 BW 9C1
Usual Suspects, LT4 Stuff, SEO Stuff, Alien stuff, etc..
From: Basim Jaber
Date: Tue, 21 Jul 1998 12:06:26 -0700
Subject: RE: figured you could respond
William,
>Well, after calling the dealer and specifically asking if my AIR pump was
covered under the emissions warranty, I took the BeaSSt in today and was
told it is not! I have 50K+ miles now, and the dealer said that only the
PCM and Cats are covered up to 80K miles. And he'd charge me $60 just to
diagnose the problem!
Your service advisor is wrong. The AIR system's sole purpose is to reduce
emissions at warmup/startup and at idle. It is most definately covered under all emissions warranties. Take your car to another dealer and
mention TSB #77-65-13 which replaces the entire AIR system with a heavier
duty routing system and AIR pump. The initial problem is caised by moisture
entering the system and and ruining the AIR pump (merely an electric motor).
If the dealer still gives you problems, call the Chevrolet Customer service
hotline (anyone recall the 800#?...please post it to the digest) and tell them the situation and mention the TSB
number.
Basim Jaber, #1859
From: Basim Jaber
Date: Tue, 21 Jul 1998 21:22:46 -0700
Subject: Final word on the AIR pump TSB...
If you have a problem with your AIR pump, don't go out and buy a new one.
Even if GM says it's not covered under warranty (as long as your still under
warranty), you can still get it replaced for free. The TSB is the key!
Since the TSB is about 8 months or so old, you can still argue this one.
However, if your PCM doesn't exude the symptoms described in the TSB, then
you're going to have a tough time. A sure shot candidate for the TSB is if your
PCM has the DTC P0410 stored in it's bank(s). This is the ESSENTIAL DTC
that will help you get the TSB performed. The dealer will at first want to
replace just the AIR pump alone. Don't fall for this fix as that fixonly
remedies the symptom and doesn't eliminate the cause. The cause is the
faulty routing in the stock AIR system. The new AIR system has all new
(and heavier duty) AIR routing, solenoids, check valves, AIR pump, and
circuitry. Read that last sentence again....note that the TSB INCLUDES THE
NEW & IMPROVED AIR PUMP.
Get those PCM's scanned and watch for that P0410 DTC error.
Basim Jaber, #1859
Subject: parts inquiry
Date: Tue, 14 Jul 1998 16:12:24 -0400 (EDT)
From: dal slabaugh <lockitup@bright.net>
To: kdrolt@sonetechcorp.com
hi ken, you had asked for info on the tsb on the air pump. parts are as follows:
12554580 pump 122.82 each
22048212 ck,valve 11.51 each
12558522 kit 107.00 each
let me know if you need more info,
thanks
dal
Subject: Long-winded check engine light saga
From: "Sellers, Scott"
Date: Mon, 19 Jul 1999 12:01:48 -0500
I hope this post provides some info/hope to others suffering from air pump
problems. If nothing else, maybe you'll find this an interesting read
(yeah, whatever).
Let me also preface this with the fact that I have considerably more timethan
money. And I'm short of time. That explains my
"interesting" approach to addressing problems with the beast.
I've had intermittent trouble with the air pump on my '96 SS for the past couple
years. The first hint of trouble came when the check engine light burned
bright on my instrument console. Excited at the prospect of my engine
checking out, I took the beast to a local shop recommended to me by a coworker
who was happy with the work the shop had performed rebuilding the engine on his
'77 Corvette. The shop owner reported that from the DTCs he scanned the
problem was either a bad air pump or bad 02 sensors. He said that he would
first replace the sensors to rule them out as the culprits. He replaced
them and found they weren't the problem. Bad air pump. When the shop
owner saw me gag and turn green when he quoted his price to replace the air
pump, he suggested I could just live with it until I won the state lottery or I
could replace it myself if I was familiar with the operation of a wrench.
Confident I understood the righty-tighty, lefty-loosey principle, I paid the man
for his diagnostic work and took the beast home, planning to buy a new pump and
replace it myself.
I called The General and asked them how much they wanted for a new air pump.
After hearing GM's price, I think the lull of silence on my end of the line was
long enough to convince the guy at the parts counter that he wouldn't get this
sale. I then decided some tinkering was in order.
After blowing several inches of dust off the socket set, I proceeded to yank the
air pump. Ten minutes later, I had the thing off the beast and in pieces
on my kitchen table. It wasn't too difficult to pry the plastic housing
from the metal base plate. Just a few plastic tabs and some insta-gasket
material holding the thing together. Once I saw the innards of this thing,
I again gagged at the thought of the price that this piece-of-junk part
commanded. It is comprised of a small electric motor, a cheap cast-metal
base, an ill-engineered solenoid-actuated valve, and a plastic housing. I
deduced that what happened to my pump was damp air entering the pump rusted the
valve actuator rod in the closed position. When the pump got the signal
from the engine to deliver air, the little electric motor kicked in and spun
like a rabid squirrel on crack. However, because the valve wouldn't open,
the little electric motor spun it's heart out in vain. The oxygen-deprived
exhaust manifold never got the air. I liberally coated the actuator rod
with Breakfree CLP, a firearm lubricant/rust preventative. I worked the
actuator rod until it moved freely within the solenoid housing. I cleaned
off the old gasket material, applied new gasket material, and reattached the
plastic housing to the metal base plate. I reinstalled the pump in the
beast.
I fired up the engine. Lo and behold, no check engine light! I
happily drove the car for several thousand miles with no reoccurrence of the
problem. However, that didn't last. Again, the check engine light
taunted me from behind its clear plastic fortress. It was intermittent at
first, then blazed with the constant brightness of a thousand suns. I
suspected the air pump again. I removed the godforsaken part and ripped
the plastic housing from its metal base, relubed the sticky actuator rod, and
reinstalled it. Unfortunately, the check engine light still burned
brightly. I tried the procedure again, taking particular care to
reassemble the pump to rule out the possibility of an air leak or other error on
my part. Still no luck. At that point I gave up.
Occasionally, ever-observant passengers would helpfully point out, "Scott,
your check engine light is on!" My hysterical reply would be,
"Oh my god, I didn't notice that! The engine must be about to explode! Where will
we get water to put out the fire here in the middle of the desert?"
Oddly enough, no passengers shared my sense of humor.
So, I was reading the digest about a week ago and saw a thread about an issue
with O2 sensors. One tip offered was to check the air pump fuse. Duh. I wrote myself a note and then ignored it until a chance incident
occurred this past weekend.
Leaving the local gun show Saturday morning (really) I put the key in the
ignition, twisted, and listened to the harrowing throes of a dying battery.
Arrrgh. I can't complain - I got four trouble-free years from that
battery. I lifted the hood, thinking this would attract the attention of
300 guys named "Bubba" with NASCAR-endorsed, Dale Earnhardt
collector-edition jumper cables. While I waited for the bait to work, I
remembered my note and checked the fuse. The fuse was OK. I also pulled the air pump relay
switch from the fuse block, because hey, you have to see what's underneath,
right? Male contact prongs protrude from the bottom of the relay and
corresponding female contact receptacles occupy the fuse block. What a
revelation. The bait finally worked. A guy asked if my battery was
on the blink. I replied in the affirmative. He offered not only to
give me a jumpstart but also helped me push the beast uphill out of the parking
spot I was in so his jumper cables would reach my battery. The well-spoken
gentleman finished his task, and I thanked him profusely while quietly scolding
myself for my preconceived stereotypical attitude about gun show attendees.
I replaced the dying battery yesterday evening. I did a test start to make
sure the new battery had a full charge. The LT1 growled to life with no hesitation. I killed the engine after a minute or so. Didn't glance
at the instrument panel.
I started the car this morning to make my trip to work. As the car was
idling in the driveway as I selected a CD for the morning drive, I noticed I
could see past the glare from the instrument panel. The irritating glow
from the !!@&@**! check engine light was strangely absent.
Now I don't know if disconnecting the battery gave the computer a chance to
reset itself, or if taking out the relay had something to do with it, or if the
air pump gods saw fit to bless me, but the light stayed off the entire 5 miles
to work. I know that's not much of a litmus test, but considering that
damned light as been burning for the past 15 or 20k miles, I think that's fairly
significant. I'll be interested to see how long the light remains off.
Maybe the full-power voltage from the new battery simply burned out the bulb.
FWIW,
Scott Sellers
Austin, TX
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