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32K views 25 replies 4 participants last post by  le0n 
#1 · (Edited)
NO SPARK needs ECU-ECM

2001 golf 2.0 5speed GL. no spark, fuse29 15a blown . I replaced the fuse and the same results. I did not pay attention to wether it blows as the ignition is turned on or while cranking. I'm away from home so i'm on my way to get more fuses,, a test light, and a volt ohm meter. someone wave a wand and make those elusive electrons reappear! I'm 58 was a vw/porsche mech. in the late 70's but went to deliver at fedex for 20yrs, so i'm only semi clueless. Thanx in advance . Jack
 
#3 ·
Hey, I was born in pittsburgh in 54 and lived there till 65.....The incline, gum bands, Isles chipped ham..yeah. there is more to the story but i was trying to go simple. Got the car from a neighbor and all that was wrong was a recurring dead battery issue. I had a fleet type mechanic friend install a battery but still a no start. the prior owner had road service jump it 2x with no problems. so... I'm in oregon and the car is in reno. I have it towed to the vw dealer thinking it need a reflash, lost memory,codes ect. Turns out ...4 bent intake valves and the timing belt out of index by about 1/4 turn. but the belt pullys and tensioner all seem fine. I order and install a rebuilt head, belt kit, waterpump tensioner. install goes fine all timing marks lineup triple checked and tensioner within range. go to start and no spark, and i find the fuse thing. went to the parts store and got some fuses and test lamps to ck it out tomorrow am... Its my understanding that disconnecting the battery causes all kind of issues including loosing the codes... I'm in reno now and this will be my ride home ,i hope. Thanx in advance to any and all. Plz excuse my typos ect , im on my daughters macbook and im old school pc with mouse ect...jack
 
#4 ·
I did not pay attention to wether it blows as the ignition is turned on or while cranking.
^^ find this out.

also, here's this diagram if you don't have a copy of it already (see if it matches your layout). slot #29 does not look like one that you'd want to be dealing with:
(swiped from vortex)


welcome to the VWOC and good luck.
 
#21 ·
DJ are you out there? the ecu has 2 plugs. I unplugged both and got a no blow on the fuse. Should I have tried just unplugging the smaller of the 2 first to determine if the ecu is not shorted but the smaller cable may be the problem? This assumes that the larger plug that has twice as many pins including 4 larger ones is the power into the unit.
 
#7 ·
^^ good tip, dj.

also, just to be clear. when you disconnect the battery on these vehicles, the ecu does not lose any information or settings that are vital to have the vehicle operating properly. you will however lose some DTCs and possibly the Radio station programming, etc. on the newer vehicles, some other engine mapping coding will be lost, however, the ecm will learn these functions after being routinely driven for a few days.
 
#8 ·
Remember my last bosh school was in 1980......soooo just unplug the ECU(engine control unit?) where is it located? I'll ck my semi-worthless Haynes book. should have tried to find a bentley book. i'm not a fan of cd books as they are worthless when your on the side of Interstate 80. Then again a AAA card is more useful than duct tape and mechanics wire on these cars .
 
#11 ·
HI...I have the wipers off but i can't seem to find the clips that are on the end of the plastic cowl by the fenders . Haynes referes you to photo 11.4 that they neglected to print. I can see the ecu under the cowl on the drivers side. Pry bars not an option, windshield to close.
 
#14 ·
Thanx. I unplugged the ecu and the fuse does not blow. so good news. i'd rather change the ecu than chase down 100' of wiring harness. Where should i shop for another ecu? used, remanf, on-line? I'm thinking that they are very car specific. Will a re-flash or up-load be required. I'm in Reno, Nv . Thanx Jack
 
#15 ·
#19 ·
i'd go with the used if it has some type of warranty that it will work. i believe the unit will have to be coded to your keys for security reasons. ask the vw dealership service department what is involved with the replacement and could you use a "used" unit.
 
#22 ·
To me it indicates the problem is in the box and not in the wiring, so that's good.

As far as ECU replacement, I'm not sure how it works with an immobilizer. It may need to be programmed, or you may be able to find one used and get someone to do an immobilizer defeat on it. Not positive how it works, Google may have the answers. Id check but I'm mobile right now lol.
 
#23 ·
Hi DJ, The Biz that sold me the unit said just plug it in and go, provided I correct the problem that caused the unit to fail, and I have no clue why this went out. To give you this cars history would require a half hour phone call! Again thanx to everyone, I'll let you know how it all ends. Jack
 
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