#17816 Egr Temp Sensor(g98) signal too Large P1404-35-10----Intermittent

#16785-…P0401 insufficent flow

I cleared them twice same symptom after steady cruise at 65mph.

I did a complete engine swapp earlier as I pointed out too most members on here and I did a search has many 12v have come accross this issue with carbon buildup in the intake behind the throttle housing and Egr valve. I kept everything from my old engine as I knew I had no cel lights on running it the last 2 years. I guess anything is posibble when your installing to gaskets, etc.

What do you Senior members think I should do first? Pull the throttle housing off again and clean the little orffic hole that sits right behind the small butterfly on the throttle plate? I know there are numerous write ups in searches. I'm looking for a good quick straight foward method and I'm asumming the Egr temp sensor is fine. I nevee pulled the 2 halfs apart at this time as I was concentrating on valley pan ceilling up properly and tork specks at the time. So any first suggestion or using the vag blocks for testingthis matter I'm open to all suggestion. Thanks for all your input you can suggest what steps I should take first.....

Thanks again to my trusty Audi Tech Members!!! Duane, MI

 

Duane,

Pulling the throttle-body off again etc., only gets you access to the short vertical leg of the longer total; and mostly horizontal EGR passage.

For you and other readers, as you "kept everything from (your) old engine as..." means you probably kept the OEM crankcase vent system (probable root cause) as was; and some accumulated EGR passage carbon build-up (entirely expected result and indirect CEL cause) as well. Yes "anything is possible...", but one is pretty much guaranteed a never ending parade of insufficient flow CEL's with an unpolished EGR Passage and a unmodified Crank-Case Vent System.

As you seem to know that you would be treating the symptoms <i>only</i> and not the cure, there is (a temporary fix only!) an in-car bicycle cable/electric drill method (access via the removed EGR Valve) write-up here somewhere, in tech articles perhaps? However please be careful, a frayed cable alone is a sharp instrument, a spinning frayed cable can be dangerous.

Note also that the <u>stock</u> EGR Valve to Intake Manifold Gasket is a famous vacuum leak location.

Note also that the above was written long-ago, sometime BC (before cure) developed by Mance, see links below.

A longer-term cure might involve your spare manifold(?) prep'd in advance perhaps; and topics 14 (see polish procedure), 18 (EGR theory) & 19 (Source of Oil in Intake Tract) here:

https://www.audiworld.com/forums/sho...highlight=tour

Not sure what to make of your "signal too Large ----Intermittant fault"? However perhaps it will stay away once the above is attended to.

Hope this helps.

 

Thanks Lago Blue, I know I read on it many times before I started on my engine project about cleaning the passages. First thing was first I just made sure the temp sensor harness was plugged in to begin with. I will take my spare intake and clean it this Winter and go from there. I did take the time to clean the breather hoses and vlave cover filters and throttle body before the reinstall.

Thanks again for your time and links which some I had printed out before I posted this. I wasn't just sure if I had a simple overlooked problem as I put a new vaccum line on the egr valve, etc.

Its not running rough or anything like that.

Duane

 

i was able to take a drill-bit and dig out some of that gunk by hand as a temporary fix, lasted about 4-5 monthalso i would recommend running seafoam thrum the intake manifold and thrum the gas tank, fairly easy procedure, just make shore your neighbors know what your doing and that your car is not on fire ;-)

p.s. i would replace that sensor, its not that expansive

 

Hey guys,

I've spent a few days really chewing on this, and waiting to see what other (and more experienced) people had to say. Let me throw something at you, and you can either nod your heads or give your monitors the middle finger as you see fit, but I think it's possible we're barking up the wrong tree here...

P1404 means that your EGR valve is stuck closed.

P0401 supports this, as it tells you your EGR has no flow.

P1435 means your secondary air injection system is not functioning properly.

P1410 is a more severe grade of P0442, or Evap leak.

So the most logical question to ask is: What system could possibly have a common link to these 4 codes? ... These components are all over the place, dammit.

But wait a minute. These 4 things do have something in common. They are each systems that are either actuated or evaluated by vacuum.

I'm not home to pop the hood right now, but I'm 99% sure that all 4 of these codes can stem from 1 vacuum leak at the little plastic "Y" vacuum junction just behind and below your throttle body. Any vacuum leak near that "Y," and anything downstream will throw a code tantrum.

It's the secondary air injection code that tells me this, because the "Y" junction I'm talking about provides vacuum for 2 things... the EGR solenoid (well, that was easy), and the cold start circuit, which probably makes you say, "What?"

Well, the cold start circuit controls the secondary air injection system, and I believe it is monitored by the earlier ECU's as a component of the Evap system, specifically because an open loop is supposed to supercede all other fuel/air mixture sensor readings.

Before you start pulling and brushing and sanding and cussing... do a butane trace of your vac lines back from each of these components. I'll bet you a dollar you'll find your issue!

 

Loud, you may be entirely correct. I took Duane's codes to be only:

17816 EGR temp signal to high; &

16785 EGR Insufficient flow detected

I assumed that other stuff was a typo, as the format was scrambled/different. Perhaps he means that 1404; 1435 & 1410 come on intermittently, while the other two are "latched" on steady after the warm-up period?

If that is the case, then perhaps there are separate faults driving the two groups?

Insufficient flow is an <i>interpretation</i> of lack of exhaust heat detected by the EGR Passage (Temperature) Sensor. It does not necessarily confirm EGR Valve closed.

 

"Insufficient flow is an interpretation of lack of exhaust heat detected by the EGR Passage (Temperature) Sensor. It does not necessarily confirm EGR Valve closed"

I was gonna say the same thing, if its seeing the wrong value from the temp sensor, its going to think its not flowing. You may just have a bad EGR temp sensor. Really, you should just pull the intake, pull it apart, and clean the passages well, and replace that temp sensor. Its only like an hour or less to pull the intake. I need to do this on my 100, i just took out the check engine light bulb in the meantime.

 

Largo, i just wrotedown exactly what it printed out off the Vag, I can do another read soon and see if it says anything differently!!

Duane

 

I do know where that tee is I know I replaced one of the black lines on it before I even pulled my engine, the other one I believe could use a new one also. Duane

 

I guess i dont know what 35-10 intermittent means either........ so it could be talking about other codes correct in short form? If thats what louds thinking about? Maybe i will wait until further instructions in what I should do first with the vag or testing

Duane.