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Pelican Technical Article:
VW / Audi ECU / DME Replacement / Upgrade

Peter Bodensteiner

 

 
Time: 20 minutes
Tab: $400-600
Talent:  
Tools:
Metric sockets and/or drivers, small screwdriver
Applicable Models:
Audi A4 (1997-02)
Audi TT (2000-04)
VW Passat (1996-00)
VW Golf (2000-02)
VW Jetta (2000-02)
VW Beetle (1999-02)
Parts Required:
None
Hot Tip:
Make arrangements with a company that can swap your chip before removing the ECU
Performance Gain:
Great power gains for money invested
Complementary Modification:
Upgrade turbo, exhaust, and/or intake for more power gains
 
   

   

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     The single fact that this modification is possible is perhaps the main reason that the Volkswagen/Audi 1.8T is so popular. In a nutshell, a simple chip swap for the engine’s computer unleashes a power increase of about 25 percent, without having to make any additional changes to the car.

     Thus, despite being a small-displacement engine, and despite the fact that larger engines are available in most of the same chassis, the 1.8T can easily be tuned to deliver equal or greater power than those larger engines, thus providing a lighter, cheaper solution for enthusiast owners. Plus, because a chip swap is so non-invasive, and inexpensive, in relation to the power that is gained, it’s a no-brainer for almost any 1.8T owner. The main consideration is that your car will be out of commission while the ECU is out, so you must plan for that.

     The ECU is pretty easy to access and remove. The hard work of this project is done by the vender of your chip. Once you extract the ECU from your car, you pack it up and ship it to them. The vendor removes the factory chip, replaces it with the new chip, and sends it back to you. The new chip contains custom programming that increases the turbo boost the engine sees; in addition, it directs changes to the fuel injection and ignition timing to make the most of that additional boost, increasing performance substantially yet within the limits of the car’s stock components. And yes, a custom tune combined with an upgraded turbo, injectors, intercooler, and/or fuel injectors can make even more power.

     Remember to disconnect your battery at the negative terminal before you start, and you should have the job done in 15-20 minutes.

    
You will need to remove the wiper arms in order to remove the panel that covers the ECU box.
Figure 1
You will need to remove the wiper arms in order to remove the panel that covers the ECU box. It’s easiest to do this by “parking” the wipers in the up position. Simply kill the ignition when the wipers are where you want them. Then, disconnect your battery at the negative terminal.
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The ECU resides under the plastic cowl cover that spans the area between the engine firewall and the base of the windshield.
Figure 2
The ECU resides under the plastic cowl cover that spans the area between the engine firewall and the base of the windshield. Refer to the cabin filter replacement article for a more detailed examination of this panel; if you’ve removed it before, it should be easy to do it again. Start by removing the rubber weather-stripping at the leading edge of the cowl cover.
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Pull the cowl cover toward the front of the car and lift it out of the way.
Figure 3
Pull the cowl cover toward the front of the car and lift it out of the way. The ECU is enclosed in the black plastic box to the right in this photo.
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To access all of the bolts holding the lid on the ECU enclosure, remove the plastic cover at the base of the windshield.
Figure 4
To access all of the bolts holding the lid on the ECU enclosure, remove the plastic cover at the base of the windshield. The lower windshield cover is split into two pieces - you only need to remove the half on the driver’s side. Start by removing the trim clips. Next, two Phillips-head fasteners help hold the piece to the bottom of the windshield. Turn these 1/4 turn counter-clockwise to release them
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To remove the wiper arms, first use a flat screwdriver to pry the round cap from the pivot of the wiper.
Figure 5
To remove the wiper arms, first use a flat screwdriver to pry the round cap from the pivot of the wiper.
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Use a 13 mm socket to loosen and remove the nut from the wiper pivot.
Figure 6
Use a 13 mm socket to loosen and remove the nut from the wiper pivot. Lift the wiper arm away from the windshield to release the tension pressing the wiper arm to the pivot, which should make it easy for you to lift the arm off of the pivot. These get tightened to 12 ft-lbs when you reattach them.
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Here is the lower windshield panel with the wipers removed.
Figure 7
Here is the lower windshield panel with the wipers removed. Now just lift it away.
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With the lower windshield panel removed, you can see the entire perimeter of the ECU enclosure, as well as the windshield wiper motor and linkage.
Figure 8
With the lower windshield panel removed, you can see the entire perimeter of the ECU enclosure, as well as the windshield wiper motor and linkage.
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Use an 8 mm driver or socket to remove the five bolts that secure the top cover of the ECU enclosure.
Figure 9
Use an 8 mm driver or socket to remove the five bolts that secure the top cover of the ECU enclosure. These bolts have a coarse thread and should only take a few turns to remove.
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The cover has a rubber gasket around its perimeter, so it may take a little light prying to lift it up and away from the bottom of the ECU enclosure.
Figure 10
The cover has a rubber gasket around its perimeter, so it may take a little light prying to lift it up and away from the bottom of the ECU enclosure.
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Use a flat screwdriver to pry away the metal clip holding the ECU in place.
Figure 11
Use a flat screwdriver to pry away the metal clip holding the ECU in place. Insert your screwdriver as shown and then tilt it toward the passenger side of the car.
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Now the ECU is loose and can be lifted up gently.
Figure 12
Now the ECU is loose and can be lifted up gently. Keep in mind that it is still connected to the car’s wiring harness.
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The ECU has two multi-pin connectors.
Figure 13
The ECU has two multi-pin connectors. No need to pull or twist them; simply pull the clip for each connector away from the ECU. The connector is equipped with a mechanism that will push it away from the ECU as you pull the clip away.
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The clip should have more than an inch of travel, and the connector should automatically release from the ECU.
Figure 14
The clip should have more than an inch of travel, and the connector should automatically release from the ECU. Here you can see the extend of travel of the connector clip. Do the same for each of the two connectors.
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Here is the business end of the ECU, showing the configuration of the two connectors.
Figure 15
Here is the business end of the ECU, showing the configuration of the two connectors.
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When your ECU comes back, use the clips to secure the wiring harness to the ECU again, letting the clip mechanism pull the connection together.
Figure 16
When your ECU comes back, use the clips to secure the wiring harness to the ECU again, letting the clip mechanism pull the connection together.
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17
Figure 17
The rest of the job is the reverse of what you’ve done above. Return the windshield wipers to the rest position before reconnecting the battery to prevent them from going out of sync.
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Comments and Suggestions:
Ace Comments: I have a a4 1.8t manual took it into audi they say its running 3 cylinders and i need a new ecu they r goin to over charge me for it of coarse so i said ill try and find 1 on ebay then they said it needs to be these numbers here8d0907557cx or 8d0997557t looked everywhere buy couldnt find then audi said they have to australian marketed , does these numbers exist
October 20, 2014
  Followup from the Pelican Staff: I don';t have access to cross-reference the numbers. Give our parts specialists a call at 1-888-280-7799. They can help you find the right part.
- Nick at Pelican Parts
 
Horakio Comments: Thanks for your answer. ECU and DME are the same? If they are failling, there must be registered fault codes?
August 28, 2014
  Followup from the Pelican Staff: Yes DME can be ECU. There may not be fault codes stored. - Nick at Pelican Parts  
Horakio Comments: Hi. I have a 1998 Audi A4 1.8T with immobilizer problem that prevent engine starting sometimes. I know that the antitheft software is located in the ECU, so can I disable the immobilizer or antitheft system inside ECU? Thanks for your help
August 27, 2014
  Followup from the Pelican Staff: It can't be disabled. The issue could be in the DME or the instrument cluster. Check the vehicle for fault codes. - Nick at Pelican Parts  
Titansccore Comments: I have a Chrysler Sebring 2.0 diesel 2008 car. I get a noise coming from the ECU after the engine is switched off. Sometimes it sounds like a buzz or some kind of depressurization. When I put my hand over it I can actually feel the vibrations coming from the unit. Close by is the abs pump but no vibration or sound comes from it. ECU P/N 0533700AF
June 17, 2014
  Followup from the Pelican Staff: The vibration is normal, it is from the ABS control unit. - Nick at Pelican Parts  
Jessica Comments: Pls help. I own an '02 vw jetta. Immobilizer nightmare. VAGCOM is throwing a mess. Stating ECU disconnected.??? Severak guys have checked all fuses.Afraid someone may have accidentally bumped sonething while underneith steering column. I know where ECU is located don't know where to check the connection. Trying to reprogram new vw valet key just bought from dealer, we erased alk codes...still saying ABS & AIRBAG NO CONNECTIOn.??,,, PLEASE PLEASE HELP. ME
April 14, 2014
  Followup from the Pelican Staff: What fault codes do you have? Can you share the complete scan of the vehicle? It's possible you have a bus problem or the ECU is faulty. - Nick at Pelican Parts  
Benjiauto Comments: do I need password to program ECU?
March 27, 2014
  Followup from the Pelican Staff: You may need a PIN. Depends on the year. - Nick at Pelican Parts  
dannyboy Comments: so you think it would work just need keys/immobilizer programming?? or is it a wild guess
November 12, 2013
  Followup from the Pelican Staff: You will need to program the new VIN so it matches in the modules involved with anti-theft. Which requires a security pin number. This number is tough to obtain. Locksmiths and the factory use to have access to it. I believe locksmiths still can get it. The dealer no longer sees the number, it is all done via pass-thru programming. Hope this information helps answer your question.- Nick at Pelican Parts  
dannyboy Comments: hi does any know, I have a 1.8t Passat 02 reg 150 bhp will the audi tt225 ecu plug in is the wiring the same I now of a injector change plus possible key programme any help would be appreciated thanks in advance, dan
November 10, 2013
  Followup from the Pelican Staff: If it plugs in, it won't run. The VIN is programmed into the ECU, the antitheft software won't allow it to start.- Nick at Pelican Parts  
Jay Comments: I now have my ECU out of my Audi TT mk1, it's still sending messages but is give electrical engine faults. I lol now if these problems in the TT mk1 but is it repairable??
August 19, 2013
  Followup from the Pelican Staff: I don't understand your question. I can try to answer it. If the ECM is faulty, it may be able to be repaired by an ECM repair company. - Nick at Pelican Parts  
mia Comments: My current ECU is not working properly...can I use a different chip or get a new ECU for my 2001 audi A6
July 20, 2013
  Followup from the Pelican Staff: We don't carry an aftermarket chip for your A6, although there may be some Audi aftermarket suppliers that make one. You can certainly get a new ECU if yours in not working properly. -  
john Comments: Whaat kind of car was on that picture because i know its not a passat.
November 15, 2012
  Followup from the Pelican Staff: The vehicle:
Year: 2000
Make: Audi
Model: A4
Trim Level: 1.8T quattro
Body Type: 4 Door Sedan
Fuel Type: Turbo
- Nick at Pelican Parts
 

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  Applies to: 2000 Audi TT, 2001 Audi TT, 2002 Audi TT, 2003 Audi TT, 2004 Audi TT, 2001 A4 Quattro, 1996 Passat, 1997 Passat, 1998 A4 Quattro, 2002 Beetle, 1998 Passat, 1999 Passat, 2002 A4 Quattro, 2000 Passat, 2000 Golf, 1999 A4 Quattro, 2001 Golf, 2002 Golf, 2000 Jetta, 2001 Jetta, 1997 A4 Quattro, 2002 Jetta, 2000 A4 Quattro, 1999 Beetle, 2000 Beetle, 2001 Beetle
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