MKIV Ignition Coil Harness Full Replacement ---- DIY
For 2002 automatic transmission vehicles the following alterations will need to be made to your new harness before installation.
- The speed sensor connector will not be used (Connector will heat-shield bag). Cut and tape back the wire where it branches out from the rest of the harness
- Pins 2 and 3 that go to the 14-pin connector will not be used, only pin 7 on the connector will be replaced. Cut these and tape them back as you see fit.
For 2001 automatic transmission vehicles
- The speed sensor connector is used and replaces the current sensor.
- Remove male terminals from cavities 2, 3 and 7 of the 14 pin connector.
- Insert terminals 2, 3 and 7 into cavities 2, 3 and 7 of the 14 pin connector.
- Reinstall the 14-pin connector.
I just did this modification myself and I found it very hard to find any information pertaining to how exactly to go about this process and had particular trouble with the connector pins and removing the wire terminals that were necessary to remove the old wire harness and install the new one.
Regardless I spent a very long time trying to find info about the two separate connectors that need to be accessed and ended up being able to fabricate a small little tool for the tiny pins and bought two other wire picks to release the slightly larger ones.
LEGAL: Please know that I am not responsible for any damages or items that you may accidently alter during this process. I am simply trying to help out those that want to do this themselves but just haven’t been able to find all the information they need to feel comfortable to do it themselves.
Thank you and I hope this helps everyone out. Now let’s get started.
Tools you will need:
Coil Pack Wiring Harness Replacement (http://www.ecstuning.com/Search/Igni...arness/ES7679/)
10mm socket wrench
Terminal extractor picks
YOU WANT THIS KIT IF YOU WANT TO CUT DOWN ON YOUR INSTALL TIME AND CURSE WORDS
http://www.napaonline.com/Search/Results.aspx?Ntt=725168&Ntk=Keyword&Nty=1&N=0 (Pictured below)
Fabricated extractor pick (Made from two small safety pins taped together)
Lots of electrical tape or heat resistant wrap (3M self-fusing tape has been suggested)
Before we start make sure you have your radio code if you are using an OEM radio as this will be needed after you reconnect the battery.
Remove both engine covers using a Phillips screwdriver and pull off your battery cover as well.
Let’s start with removing the battery. Using your 10mm socket remove both terminals from the battery and lift out of the car.
Next let’s remove the air box, which requires a 10mm socket along with a Phillips screwdriver. Remove the two bolts holding in the air box and then loosen the clamp on the larger hose next to the MAF.
Make sure to remove the MAF connector clip as well and put it up out of the way. At this point it just takes a little bit of maneuvering to pull the box up and out. As you remove the air box you’ll notice another hose connected to the left side. Simply pinch the connectors and move it out of the way as well.
You’ll want to cover the MAF sensor with something so as to avoid dust and other objects from getting inside it while it is off your car. I use a latex glove fitted over the opening.
Now it is possible to remove the battery tray that was exposed when you removed your battery. This requires the removal of four bolts using your 10mm socket.
Now remove the vacuum air duct from the left fender by removing one 10 mm bolt with your socket.
Now remove the engine harness cable duct by releasing the bottom two clips and two other set leading up to the rain tray. (I just used my Volkswagen key to release the tabs worked like a charm.) You can disconnect the lone connector that is exposed when you remove the cover as well.
Now you will need to remove your wiper arms and the rain tray. I will include an attached article on how to do this from an ECU install DIY as I don’t want to take that whole thing off again. If you have any problems with it feel free to message me and I will help out as best as I can.
Okay, now that you have access to all the wires you are going to need to work with this is where it can get tricky and where I myself had the most trouble.
Begin by locating the two connectors located inside the left fender wall right next to where the battery sits. Once you have removed and disconnected these from their holder on the wall you want to grab the connector pictured below.
You will need to first remove the cover off the back of the connecter which just requires releasing a few tabs to reveal the wires and then release the secondary locks by sliding a small screwdriver (one from an eyeglass kit works well) into the two slots on both the top and bottom of the connector pictured above.
Once this is done you can begin the process of removing the appropriate pins that will need to be replaced. Once you find the pin you need you will either need to use the fabricated tool or the two green handled tools I had shown before.
Here are some examples:
Once you have inserted either tool I pressed down on the pin from the top with an allen wrench to get the pin released enough to pull the wire out from the bottom.
This took me several tries with the smaller pins to get the safety pins set in the holes right but just be patient and take your time and you should be okay. The key is to not get frustrated.
Once you have removed the appropriate pins it is now time to do the same with the ECU connecter which you exposed earlier. You are going to be removing the right hand side connector by pulling on the handle on its right hand side to release it from the ECU.
Once you have the connector off the ECU there are a couple of secondary locks you must remove. The three locks are pictured below.
Once you have the locks removed you can then pull out the two small sets of connectors to get access to the wires you need to release.
To remove these pins just insert a safety pin to the side of the hook in the slot as shown by the arrow. There is also one larger pin that you can use the two picks to release as well.
The smaller pin numbers are very hard to see but are labeled on each side of the white and black housings. (use your magnifying glass) You will have to count from either side as they are only labeled on the ends. Once you have all these wires out time for some more fun.
Now to expose your old wiring harness and begin to pull it out of the engine bay.
First remove your vacuum reservoir from the top of your valve cover. This just needs a 10 mm socket and an allen wrench (I’m not sure of the size.)
Now begin by unclipping the four connectors from your ignition coils. You will have to decide how to get the harness out of the car. (If you want to pull from the valve cover and out or pull the connectors down under the diverter valve and out. (I did it the second way.)
After you unclip the connectors, you will need to remove another connector from the speed sensor (manual transmission only). This is located beneath your diverter valve and will have a heat shield around the connector’s wiring.
The tab for the connector is on the underside and I had to jack up the car and go underneath to release it.
Now you will need to expose all of the wires leading from the harness up to the ECU. It is very important to you make sure you keep the right wires in the correct groups as you go about this as all of the wires do start together but then start diverging to their respective locations.
I used colored zip ties to designate the different groups of wires and it worked great keeping the wires organized.
I unplugged some other harnesses along the way to make room for the old harness removal and the insertion of the new one.
Now that you have the wires exposed you can begin to pull the old harness out. I just started from the ECU and threaded the wires I had removed back down the cable duct and grabbed the single connector in the duct and the other pins from the first connector along the way and routed them all the way back to the original harness.
Once you have the old harness out the install is just the opposite. Route the new wires along the same line as the old ones and once you reach the first pin connector simply find the correct slots and slide those suckers all the way in until they lock.(verify by lightly pulling on the wire to confirm it is in fact locked in.)
Connect the single pin connector as you go up the wire duct and then slide the five pins into their corresponding slots on the ECU. Now when replacing the white and black housings into the connector make sure to orient them in the correct direction.(the connector has numbers located above and below the housing slots.) Once again your magnifying glass will come in handy for this.
Make sure the housing are all the way in or else its secondary locking pin will not go back into the slot.
After you have verified that all of your connections are sound you can begin using your electrical or thermal tape to reinsulated the wires you have exposed during this process. Take your time. You don’t want other wires cracking and becoming exposed because you were in too much of a hurry to finish this up.
After this is complete simply reattach all of the connectors that you rewired and any others you unclipped to make room and begin installing all of the items you had to remove at the beginning of this DIY.
Thanks to everyone on the Vortex. I decided it was time for me to finally take the time and give back to the forum after it has helped me so much with repairs and modifications on my own car.
Any questions or anything I may have missed that needs clarification please let me know and I will do my best to update and/or fix ASAP.
Oh and treat yourself to several beers after and while doing this. You'll need them. I sure did haha.