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Check Engine and 4 psi of boost in my '01 A4 1.8T

Old Apr 11, 2005 | 12:52 AM
  #1  
audigirl929's Avatar
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Default Check Engine and 4 psi of boost in my '01 A4 1.8T

Hi guys!

My check engine light is on and luckily, someone helped me download the codes. Here they are. The only code that had any "comments" in it was the first one. The rest didn't say anything else so I just wrote down the trouble code and description.

Could anyone help me with my car? It's a 2001 A4 1.8T. I'm going to a driver school soon and would like to get it fixed before then.

Thanks!!!

Trouble Code : P0444
Description : Evaporative Emission Control System Purge Control Valve Circuit Open
Comments :
Engine Status
Fuel Pressure (Gage) :
Intake Manifold Pressure (Absolute) :
Engine Coolant Temperature : 113.00 °F
Calculated Load Value : 3.5 %
Engine Speed : 800 RPM
Vehicle Speed : 0 MPH
Fuel Trim Status
Short-Term Fuel Trim (Bank 1) : 0.00 %
Short-Term Fuel Trim (Bank 2) :
Long-Term Fuel Trim (Bank 1) : -0.78 %
Long-Term Fuel Trim (Bank 2) :
Fuel System Status
Fuel System 1 Status :
Fuel System 2 Status : Open loop; has not yet satisfied conditions to go to closed loop.

Trouble Code : P0037
Description : HO2S Heater Control Circuit Low (Bank 1, Sensor 2)
Trouble Code : P0418
Description : Secondary Air Injection System Relay "A" Circuit
Trouble Code : P0412
Description : Secondary Air Injection System Switching Valve "A" Circuit
Trouble Code : P1289
Description : Unknown Powertrain DTC (Manufacturer Controlled; Fuel and Air
Trouble Code : P1472
Description : Unknown Powertrain DTC (Manufacturer Controlled; Auxiliary
Trouble Code : P0031
Description : HO2S Heater Control Circuit Low (Bank 1, Sensor 1)
Trouble Code : P0136
Description : O2 Sensor Circuit Malfunction (Bank 1, Sensor 2)
Trouble Code : P0102
Description : Mass or Volume Air Flow Circuit Low Input
Trouble Code : P0135
Description : O2 Sensor Heater Circuit (Bank 1, Sensor 1)
 
Old Apr 11, 2005 | 01:25 AM
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Default RE: Check Engine and 4 psi of boost in my '01 A4 1.8T

Welcome to Audi Forums audigirl929!

Since you're new... check out the START HERE! (click this link) link to get a rundown of the lingo/vocab here at audiforums.

Then be sure to search the archives when you have a question. Chances are the question has been asked before (probably several times) and the archives will have plenty of information to answer your question. If you still need answers, please feel free to ask questions.

Don't feel intimidated; we are all a bunch of pretty cool guys (and gals). Feel free to post advice, comments, ideas, suggestions, and even pics.
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Good to see a GIRL on the forum.

I don't have my reference CD tonight... or I'd be able to answer all these questions. I'll have it up and running tomorrow if nobody responds with anything concrete today.
 
Old Apr 11, 2005 | 02:17 AM
  #3  
audigirl929's Avatar
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Default RE: Check Engine and 4 psi of boost in my '01 A4 1.8T

Just to add, I have the APR chip and exhaust - but I never had any problems with it for the 3 years I've had it (and no, me modding the car was not boyfriend induced - a lot of my female friends ask me that). Although I'm still getting 4psi of boost (vs. 10ish stock and spike to 17ish APR'ed), the car does run smooth with no hesitations. It just won't go to full boost. Although we "resetted" the check engine light, it will come up again after the 2nd engine start. A mechanic told me that the system won't go to "closed loop" - but I have no clue as to what that means. They found no broken hoses, changed spark plugs, and changed the air filter. The problem is still there... And today, the AC doesn't seem to be blowing cold air. My baby is falling apart approaching 100k miles.

Thanks in advance for anyone who can help me!
 
Old Apr 11, 2005 | 03:23 AM
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Default RE: Check Engine and 4 psi of boost in my '01 A4 1.8T

Wouldnt a bad diverter valve cause the car to yeild low boost levels?

No idea on the CEL's though....
 
Old Apr 11, 2005 | 03:28 AM
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Default RE: Check Engine and 4 psi of boost in my '01 A4 1.8T

i know you said the mechanic checked your vacuum hoses but i think they should be checked again


reason being the number of secondary air injection codes and the mass air flow codes.


do you have acess to a repair manual? bentley has good diagrams of the evap system routing.

i am guessing a leaking hose or maybe a bad combination valve to secondary air injection pump.

that valve is commonly know to go bad. it is located between the back of the valve cover and the firewall
 
Old Apr 11, 2005 | 03:32 AM
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Default RE: Check Engine and 4 psi of boost in my '01 A4 1.8T

oh yeah, i am guessing you have a boost gauge.

also check the hoses and fittings where it is tapped in.
 
Old Apr 11, 2005 | 03:35 AM
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Default RE: Check Engine and 4 psi of boost in my '01 A4 1.8T

one last thing, check all of the one way check valves in the evap system as well
 
Old Apr 11, 2005 | 12:41 PM
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Default RE: Check Engine and 4 psi of boost in my '01 A4 1.8T

w/o fixing these problems ur not going to be able to boost past stock boost bc ur car is in limp mode..this is a saftey mod for when ur check engine light comes on so untill u fix this problem ur not gonna see any boost.
 
Old Apr 11, 2005 | 01:50 PM
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Default RE: Check Engine and 4 psi of boost in my '01 A4 1.8T

thats why i got the 2.8
 
Old Apr 11, 2005 | 02:40 PM
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Default RE: Check Engine and 4 psi of boost in my '01 A4 1.8T

I can take the boost gauge hose out of the equation by un-Ting it from the hose coming out of the intake manifold. I'll try this out today during lunch.

>>>i am guessing a leaking hose or maybe a bad combination valve to secondary air injection pump. that valve is commonly know to go bad. it is located between the back of the valve cover and the firewall

Black B5: Can you post a pic as to where this might be?

>>Wouldnt a bad diverter valve cause the car to yeild low boost levels?

I assume that if I had a bad DV, that the boost would be "erratic" and the car would run crappy (hesitates, stalls, etc.)??? 'Cause right now, it's pretty contant at 4 psi and the car runs pretty smooth...just slow...
 

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