Throttle valve servo failure?

Tiny
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  • 2004 SATURN L300
  • 96,000 MILES
Hello and THANKS for your time.

ok. Far from being a tech but I do a lot of my own repairs. Here is my situation.

car wouldn't start in morning. Turns over, no start. With key on, ticking sound from engine, sound is the throttle plate (butterfly valve) trying to open and then closing, a couple of times a second, ticktickticktick. Pressing the accelerator pedal has no affect on throttle position.

i bought an actron cp9125 code scanner, but it won't read any codes, just keeps saying "no link". Scanner works on a '97 ford.
so i'm thinking maybe the throttle position actuator failed? The throttle bore was pretty dirty, I sprayed it with cleaner but no luck.

i understand that the actuator isn't serviceable, so the whole unit would need to be replaced.

it's hard to tell what warning lights might be on, on the dash, but the check engine and the service engine (wrench icon on the saturn) lights stay lit when the key is left on. I don't know if they would go out if the car was running.

i've searched a little but didn't see this problem.

any help is appreciated,

TIA,

doug
Monday, June 4th, 2012 AT 9:50 PM

16 Replies

Tiny
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What worries me is your code reader says no link if the throttle body assemble failed you should still be able to read codes in the ecm. If the code reader is good you have a wiring problem or a bad ecm.
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Monday, June 4th, 2012 AT 9:54 PM
Tiny
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YIKES!

THANKS much for the fast reply!

I've had no electrical problems before, this was out of the blue. I bought the car with 64,000 miles on it and have only replaced the fuel pump.
I was sooooo hoping for an easy fix. I guess I could just throw parts at it or. Better yet, I guess i'll have to get to a repair shop. I'm due for the timing belt anyway.

Thanks again for your time any expertise!
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Monday, June 4th, 2012 AT 10:11 PM
Tiny
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I have seen those ecms just go and the engine wont start and you cant talk to the ecms with a scan tool. If your going to take into a shop please let us know what they find.
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Monday, June 4th, 2012 AT 10:21 PM
Tiny
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THANKS, will do.

The local chevy dealer won't do the timing belt. The closest authorized saturn repair shop that will do the belt is about 50 mi away. I haven't checked with any local independent repair shops.

THANKS again!

Doug
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Monday, June 4th, 2012 AT 10:35 PM
Tiny
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A little info on that timing belt and the engine is its the same as the caddy catera model except the caddy one is mounted for a rear wheel drive application with a different intake. It takes a special tool to time it correctly.
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Monday, June 4th, 2012 AT 10:44 PM
Tiny
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Update ...

car started!!

i did a little more searching and came across a post that mentioned checking the controls B+ fuse underhood. i pulled it and there was a little corrosion, cleaned it and car started and i was able to pull codes.

6 codes read (in order) ....U2105, P1779, P1791, P0123, P0222, P0700

the scanner book has the P0xxx codes but not the P1xxx codes. it says the Uxxxx is a network comm code.

in a search i found this thread where someone had some similar codes,
https://www.2carpros.com/questions/saturn-l300-2001-saturn-l300-computer-error
the P1779, P1791 codes are explained.

should this be as easy as replacing appropriate sensors? and tcm? (fingers crossed)

thanks again for your help!!

doug

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Tuesday, June 5th, 2012 AT 6:13 PM
Tiny
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If you couldnt talk to the computer because of this corrossion issue then I would clear the codes and see which codes come back. Before you go chasing codes that were set by that corrossion. Clear the codes and let me know what codes come back and we will go from there.
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Tuesday, June 5th, 2012 AT 6:21 PM
Tiny
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I cleared the codes and nothing came back immediately after running the car for a minute, so I will drive it a bit.

On a another note. My battery felt really weak, it's 1 yr old and has been strong, and was strong yesterday while cranking it, key or lights haven't been left on.
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Tuesday, June 5th, 2012 AT 6:51 PM
Tiny
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Just drove around the block a few times and no codes. I'll drive some more and see what happens.

Thanks.
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Tuesday, June 5th, 2012 AT 7:05 PM
Tiny
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Your welcome keep me posted and have your battery and alternator tested.
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Tuesday, June 5th, 2012 AT 7:07 PM
Tiny
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Ok. I let the car set for about 30 min after the drive around the block and was going to go drive for a few miles. It wouldn't start again, same thing, the butterfly was clicking open/close again. Pulled the B+ fuse again and gave it the ole in/out in/out and it started. CEL light was on, 2 codes, the U2105 and the P0700.
Cleared the codes and drove for a few miles, cut the car off twice and it restarted, got home and checked codes, no codes.

What would be in the P0700 trans control sys malfunction?

Battery was strong again. But will get batt and alt checked.

Soooo. Maybe some more corrosion somewhere? Maybe clean some grounds? I read a post that mentioned checking the ecu's ground, (on the intake manifold, I think), where would that be?

Thanks
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Tuesday, June 5th, 2012 AT 8:27 PM
Tiny
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There is a ground hooked right to one of bolts holding the ecm on the intake manifold. You have make sure everthing is clean and tight. You need to get in there and get some contact cleaner to clean up the fuse contacts. Or you have a loose connection somewhere in the underhood fuse box. The code P0700 just means there are transmission codes present. Like I said before most likely your codes are being set by your poor or corroded connection somewhere.
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Tuesday, June 5th, 2012 AT 8:35 PM
Tiny
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Me again.

Drove the car since last post, about 1k miles w/ no problems. A few weeks ago the intermittent start problem returned, pretty much same as before, throttle plate opening and closing rapidly, car would start after setting for a while. After searching the net, I replaced the crank position sensor, but the no start returned. Once after restart, trans shifted rough, clunking into gear, I got home and checked codes. Only codes this time and all the other times were, U2105 and P0700. After clearing codes, tranny shifted as normal.

These codes would only appear after a no start episode. I checked several times in between episodes and there were no codes.

Eventually, car refused to start even after sitting overnight. I've had it towed to a chevy dealer, so I can get my timing belt replaced at the same time. They are working on it now, but called earlier to say after "extra" diagnostics, the throttle body needed replacing. I guess i'll find out later today or tomorrow if that fixed it.

Wouldn't a bad throttle body throw a code?

I'll post back on the outcome, incase someone comes across this in a search, maybe it will help them.

Thanks again.
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Thursday, October 4th, 2012 AT 5:22 PM
Tiny
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Not being able to talk to the ecm isnt going to be caused by a bad throttle body they usually set codes also. Havent seen many bad 2004 throttle bodies ethier. Did you ever check the grounds under hood junction box connections etc?Also I would try replacing the main relay in the under hood fuse box they failing and cause all kinds of intermittent issues dieing no starts etc. That throttle body is a really expensive guess.
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Thursday, October 4th, 2012 AT 6:04 PM
Tiny
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Update.

So this is where i'm at.
I got the car this saturday from the dealer. They replaced the throttle body. They said it would then start but not run. Yeah, I think they were throwing parts at it. They then, replaced the ecm, and the car runs, seemingly with no problems. I had asked them to do a the state required safety & emissions inspection while they had it, as mine is due. But with the new ecm, it has codes that fail the inspection. They say it needs to be driven to learn whatever it is that it learns. I drove it home, about 40 miles, next day went to try to get it inspected and it failed. And they confirmed the drive/learn thing.

Check engine light isn't on and I can not read any codes with my cheap scanner. So I guess I need to drive it more.

I noticed my a/c doesn't work now, on the fail notice I got from the inspection station, it says :
Secondary Air System. Not Available
and
A/C refrigerant. Not Available

will the a/c start working when the ecm resets (learns)?

Also on the fail notice.

Engine Misfire. Ready
Catalytic Converter Efficiency. Not Ready
Heated O2 Sensor. Ready
Fuel System Performance. Ready
Heated Catalyst. Not Ready
EGR Flow. Not Ready
Comprehensive Component. Ready
Evaporative Emissions Control System. Not Ready
O2 Sensors. Ready

the dealer hinted at a bad catalytic converter if the codes don't clear after being driven.

Thanks!
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Tuesday, October 23rd, 2012 AT 1:23 PM
Tiny
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So you need to drive your car more to set the monitors thats about it there. As far as the ac goes you need to check your high and low side pressures to see what they read.
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Wednesday, October 24th, 2012 AT 4:11 AM

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