2001 Silverado OBD codes?

Is there a way to read the diagnostic codes on a 2001 Chevy Pickup
without an OBD-II reader? Several previous vehicles would blink the
codes to you if you turned the key on/off/on/off/on/off rapidly, or
pushed the right combination of radio buttons, etc.

My truck (34000 miles) has been hard to start for a couple of weeks. I
bought a can of fuel injector cleaner for it last week ago (which I just
put in last night. I was waiting for the gas gauge to drop below 1/2
tank.) The SES light came on yesterday morning. I'd like to see what
the codes are, especially to compare with some service bulletins for
this model. The oil dipstick smells like gasoline, but that could be my
imagination.

BTW, the truck has always gotten poor gas mileage (as bad as my old 1974
3/4 ton) but two different dealers checked that out back in 2002 and
said it was normal. Other than the poor fuel economy the truck has had
no problems at all until now. (so I don't have service manuals, etc. yet)

Thanks, and best regards,
Bob

"zxcvbob" > wrote in message
...
> Is there a way to read the diagnostic codes on a 2001 Chevy Pickup without
> an OBD-II reader? Several previous vehicles would blink the codes to you
> if you turned the key on/off/on/off/on/off rapidly, or pushed the right
> combination of radio buttons, etc.

You need at least an ODD II compliant code reader to retrieve any stored
codes. You local Auto Zone or many other national chain parts supply stores
will usualy read the codes for you for free.

>
> My truck (34000 miles) has been hard to start for a couple of weeks. I
> bought a can of fuel injector cleaner for it last week ago (which I just
> put in last night. I was waiting for the gas gauge to drop below 1/2
> tank.) The SES light came on yesterday morning. I'd like to see what the
> codes are, especially to compare with some service bulletins for this
> model. The oil dipstick smells like gasoline, but that could be my
> imagination.

One simple test for fuel in the oil that works pretty well is to place a
single drop of the oil from the dip stick onto a piece of carrogated
cardboard ( tear a piece of of an old card board box). If there is any
gasoline in the oil, it will be absorbed by the cardboard much faster than
the oil and will make a visible halo ring around the drop of oil. It's
pretty easy to see if you try it. Works better if the oil is cold, so do it
before you start up the engine in the morning, or at least a few seconds
after starting the engine. That will be enough running time to be sure any
fuel in the crank case oil hs mixed with the oil.

>
> BTW, the truck has always gotten poor gas mileage (as bad as my old 1974
> 3/4 ton) but two different dealers checked that out back in 2002 and said
> it was normal. Other than the poor fuel economy the truck has had no
> problems at all until now. (so I don't have service manuals, etc. yet)
>
> Thanks, and best regards,
> Bob
--
Disclaimer:
Due to the nature of solving problems over the internet being mostly
guesswork,
please do not consider the above recommendations as the only possible
solutions.

--
Kevin Mouton
Automotive Technology Instructor
"If women don't find you handsome, they should at least find you handy"
Red Green

Kevin wrote:
> "zxcvbob" > wrote in message
> ...
>> Is there a way to read the diagnostic codes on a 2001 Chevy Pickup without
>> an OBD-II reader? Several previous vehicles would blink the codes to you
>> if you turned the key on/off/on/off/on/off rapidly, or pushed the right
>> combination of radio buttons, etc.
>
> You need at least an ODD II compliant code reader to retrieve any stored
> codes. You local Auto Zone or many other national chain parts supply stores
> will usualy read the codes for you for free.

After I posted this I started searching for OBD-II readers. They are
not as expensive as I thought. Sounds like a good investment to get
one; maybe an Equus 3100, or something like that.

>> My truck (34000 miles) has been hard to start for a couple of weeks. I
>> bought a can of fuel injector cleaner for it last week ago (which I just
>> put in last night. I was waiting for the gas gauge to drop below 1/2
>> tank.) The SES light came on yesterday morning. I'd like to see what the
>> codes are, especially to compare with some service bulletins for this
>> model. The oil dipstick smells like gasoline, but that could be my
>> imagination.
>
> One simple test for fuel in the oil that works pretty well is to place a
> single drop of the oil from the dip stick onto a piece of carrogated
> cardboard ( tear a piece of of an old card board box). If there is any
> gasoline in the oil, it will be absorbed by the cardboard much faster than
> the oil and will make a visible halo ring around the drop of oil. It's
> pretty easy to see if you try it. Works better if the oil is cold, so do it
> before you start up the engine in the morning, or at least a few seconds
> after starting the engine. That will be enough running time to be sure any
> fuel in the crank case oil hs mixed with the oil.

Thanks. I'll try that tomorrow morning (have already driven the truck
today and got the oil hot)

Best regards,
Bob

zxcvbob wrote:
> Kevin wrote:
>>
>> You need at least an ODD II compliant code reader to retrieve any
>> stored codes. You local Auto Zone or many other national chain parts
>> supply stores will usualy read the codes for you for free.
>
> After I posted this I started searching for OBD-II readers. They are
> not as expensive as I thought. Sounds like a good investment to get
> one; maybe an Equus 3100, or something like that.
>
>>> My truck (34000 miles) has been hard to start for a couple of weeks.
>>> I bought a can of fuel injector cleaner for it last week ago (which I
>>> just put in last night. I was waiting for the gas gauge to drop below
>>> 1/2 tank.) The SES light came on yesterday morning. I'd like to see
>>> what the codes are, especially to compare with some service bulletins
>>> for this model. The oil dipstick smells like gasoline, but that
>>> could be my imagination.
>>
>> One simple test for fuel in the oil that works pretty well is to place
>> a single drop of the oil from the dip stick onto a piece of carrogated
>> cardboard ( tear a piece of of an old card board box). If there is any
>> gasoline in the oil, it will be absorbed by the cardboard much faster
>> than the oil and will make a visible halo ring around the drop of oil.
>> It's pretty easy to see if you try it. Works better if the oil is
>> cold, so do it before you start up the engine in the morning, or at
>> least a few seconds after starting the engine. That will be enough
>> running time to be sure any fuel in the crank case oil hs mixed with
>> the oil.
>
> Thanks. I'll try that tomorrow morning (have already driven the truck
> today and got the oil hot)


There was no fuel in the crankcase oil. There is a gasoline smell in
the cab sometimes right after I start the engine.

After running for a couple of days with the fuel injector cleaner, the
truck seems to have a little more power. It's still sometimes hard to
start. The check engine light went off for a day or two, now it's back
again. I've used up the half-tank of gas that had the injector cleaner
in it and I filled up with gas at the local BP (Amoco) station, so it's
running on just gasoline again.

My OBD2 reader got here today and I just checked it. The DTC code is
P0300, which means random misfires. It also has a pending code of
P0300. I printed a report and to my untrained eye everything looks OK,
/except/ the fuel trim numbers:
STFT - Bank 1 2.34%
LTFT - Bank 1 2.34%
STFT - Bank 2 -8.59%
LTFT - Bank 2 -5.47%

Should I just reset everything back to zero and see what happens? Maybe
the bank 2 fuel trim is causing the misfire? Why so much variance
between short term and long term?

There's not a whole lot to the ignition system that I can check. Each
plug has its own ignition coil, so the high-tension wires are very short
and direct. I haven't pulled any sparkplugs yet.

I haven't seen an engine in many years with so few vacuum hoses. I
should take the cover off the throttle body and check the hoses.

Best regards,
Bob

Mike wrote:
> "zxcvbob" > wrote in message
>>
>> My OBD2 reader got here today and I just checked it. The DTC code is
>> P0300, which means random misfires. It also has a pending code of P0300.
>> I printed a report and to my untrained eye everything looks OK, /except/
>> the fuel trim numbers:
>> STFT - Bank 1 2.34%
>> LTFT - Bank 1 2.34%
>> STFT - Bank 2 -8.59%
>> LTFT - Bank 2 -5.47%
>>
>> Should I just reset everything back to zero and see what happens? Maybe
>> the bank 2 fuel trim is causing the misfire? Why so much variance between
>> short term and long term?
>>
>> There's not a whole lot to the ignition system that I can check. Each
>> plug has its own ignition coil, so the high-tension wires are very short
>> and direct. I haven't pulled any sparkplugs yet.
>>
>> I haven't seen an engine in many years with so few vacuum hoses. I should
>> take the cover off the throttle body and check the hoses.
>>
>
> Take a look at your O2 sensor values, especially bank 2. The O2 sensors
> should be switching between .1 volts to .9 volts, with .1 being lean and .9
> being rich. If the bank 2 sensor is failing it may be staying on the rich
> side. This would cause the ECU to remove fuel on bank 2 as indicated by the
> long and short term fuel trim. If bank 2 is being run too lean this may be
> be the cause of the P0300 code as a lean fuel mixture is harder to ignite.
>


I don't have an O2 tester nor an oscilloscope. The diagnostic tool just
says the O2 sensor monitor and O2 sensor heater monitor are "complete"
and the fuel system status 1 and 2 are closed loop.

Would it be worthwhile to swap the banks 1 and 2 O2 sensors and see if
the problem follows the bank 2 sensor?

This engine has 4 O2 sensors; 2 before the catalytic converter and 2
after. Is the one before the converter is to monitor that half of the
engine and the one after to monitor the catalytic converter?

Can a place like Autozone check the sensor voltages and waveform?

Thanks,
Bob

With an '01 truck with that few miles my guess is that you will find
that the )2 readings should be off. Also, I'd bet that your plugs are
glazed if you drive a lot of small, short trips keeping the truck from
reaching 220 degrees. You'll probably be in need of the "top down"
cleaning that a certified GM dealer can do to remove all of the
deposits from the inside of the engine.

As far as MPG, you never stated what motor and gear ratio you have.
Also, doing a lot of small intown trips will slowly make your MPG go
down. My '01 Silverado has the 5.3 with the 3.43 ratio and about 72k
miles on it now. The only mods I've done was add a fresh air intake
and replaced the tranny fluid with Mobile 1 synthetic. On my trip to
Florida a few years ago I average 22MPG on the highway.


--
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ponchonutty wrote:
> With an '01 truck with that few miles my guess is that you will find
> that the )2 readings should be off. Also, I'd bet that your plugs are
> glazed if you drive a lot of small, short trips keeping the truck from
> reaching 220 degrees. You'll probably be in need of the "top down"
> cleaning that a certified GM dealer can do to remove all of the
> deposits from the inside of the engine.

I'll check the spark plugs tomorrow. The local Chevy dealer service
department is awful, but maybe the GMC dealer would be OK. I need to
take the truck in for a wheel position sensor recall anyway.

> As far as MPG, you never stated what motor and gear ratio you have.
> Also, doing a lot of small intown trips will slowly make your MPG go
> down. My '01 Silverado has the 5.3 with the 3.43 ratio and about 72k
> miles on it now. The only mods I've done was add a fresh air intake
> and replaced the tranny fluid with Mobile 1 synthetic. On my trip to
> Florida a few years ago I average 22MPG on the highway.

It's a 2WD with the 4.8L V8 and trailer towing package. I'm not sure
what axle ratio it has. On the highway at 65 mph in overdrive the
tachometer says... about 1900 rpm, I think. Maybe 2000. It sits a lot
without being driven because driving the Buick is cheaper; lately I have
been driving the truck quite a bit of short trips, but I also drive it
to church on Sundays which is 15 miles each way on country highway and I
thought that would blow the soot out.

When I drove down to Texas a few years ago, I think I got about 18.8 to
19 MPG.

When the truck was a couple of months old, I once got 19.8 MPG on a 500
mile trip with no load and with the tailgate down to reduce drag.
That's the best fuel economy it ever got.

Bob

"zxcvbob" > wrote in message
...
> Mike wrote:
>> "zxcvbob" > wrote in message
>>>
>>> My OBD2 reader got here today and I just checked it. The DTC code is
>>> P0300, which means random misfires. It also has a pending code of
>>> P0300. I printed a report and to my untrained eye everything looks OK,
>>> /except/ the fuel trim numbers:
>>> STFT - Bank 1 2.34%
>>> LTFT - Bank 1 2.34%
>>> STFT - Bank 2 -8.59%
>>> LTFT - Bank 2 -5.47%
>>>
>>> Should I just reset everything back to zero and see what happens? Maybe
>>> the bank 2 fuel trim is causing the misfire? Why so much variance
>>> between short term and long term?
>>>
>>> There's not a whole lot to the ignition system that I can check. Each
>>> plug has its own ignition coil, so the high-tension wires are very short
>>> and direct. I haven't pulled any sparkplugs yet.
>>>
>>> I haven't seen an engine in many years with so few vacuum hoses. I
>>> should take the cover off the throttle body and check the hoses.
>>>
>>
>> Take a look at your O2 sensor values, especially bank 2. The O2
>> sensors should be switching between .1 volts to .9 volts, with .1 being
>> lean and .9 being rich. If the bank 2 sensor is failing it may be staying
>> on the rich side. This would cause the ECU to remove fuel on bank 2 as
>> indicated by the long and short term fuel trim. If bank 2 is being run
>> too lean this may be be the cause of the P0300 code as a lean fuel
>> mixture is harder to ignite.
>
>
> I don't have an O2 tester nor an oscilloscope. The diagnostic tool just
> says the O2 sensor monitor and O2 sensor heater monitor are "complete" and
> the fuel system status 1 and 2 are closed loop.

OK. I thought you had a scan tool, not just a code reader.

>
> Would it be worthwhile to swap the banks 1 and 2 O2 sensors and see if the
> problem follows the bank 2 sensor?

That would work but it may not be possible. Some of the connectors are
keyed differently and the wires may be a different length also. If it is
possible to switch them go ahead and do so and see if the problem follows.
Another thing to try would be clear the codes, disconnect bank 2 and see if
it runs any better and see what codes you get.

If you have a multimeter and a wiring diagram you can also check the O2
voltage. The O2 sensor generates it's own voltage. With the wiring diagram,
locate the O2 sensor output wire ( signal to ECU ) and back probe it with
the red lead from the meter ( black lead goes to a GOOD ground ). Set meter
to dc voltage scale, start engine and read sensor voltage. The sensor may
need to warm up for a few minutes before it starts switching. It should
switch voltages rapidly from a high to low voltage. It should not go below
..1 volt or above .9 volt. If it switches very slowly or stays either high
or low constantly it may have failed.

You must also be aware that the O2 sensor may be reading correctly when
stuck high or low if other problems exist. For example, a vacuum leak would
cause a lean condition which would cause the O2 sensor to read lean. A rich
condition, such as a leaking injector, would cause the O2 sensor to read
rich.

>
> This engine has 4 O2 sensors; 2 before the catalytic converter and 2
> after. Is the one before the converter is to monitor that half of the
> engine and the one after to monitor the catalytic converter?

Yes, that is correct. The front sensors ( sensor 1 ) control the air/ fuel
mixture. The rear sensors ( sensor 2 ) are used to monitor catalyst
efficiency.

>
> Can a place like Autozone check the sensor voltages and waveform?

As far as I know they only have code readers.

>
> Thanks,
> Bob