QuestionQUESTION: Hi Roland,
My first chance to get in touch with you. I have had a mechanic look at the issue and he believes 90%, that it's the leak detection pump. He did a process of elimination and diagnostic...He says this will cost me $288. I took your advise in prior conversations about unplugging autoshutdown relay and switch out the fan relay and it didn't shut off, mechanic said ignition switch is good. Do you have any suggestions and or comments? The dealer who sold me this car is possibly going to help me in the cost/s to fix this problem, but they want me to be sure, as they will only help me once. I bought this car 3 weeks, ago, but AS IS, I paid $2,800 and it took most of my $. Thanks again, for your expertise and help Roland. Hope you had a great vacation! :) Anita
ANSWER: Hi Anita,
I have to differ with the mechanic as to the leak detection pump being the cause of this refusal of the engine to stop running when you turn the key to the Off position. The leak detection pump is indeed one of the very many devices that is powered by the ignition switch but I fail to see in what way it could operate so as to power anything were it faulty. It would be like the "cart powering the horse". The section of the ignition switch that powers the pump also powers:
the body computer (which runs alot of thinds not related to the engine directly, to many to list here);
instrutment cluster, ignition key anti-theft device;
instrument cluster;
power door lock switches, power mirror;
fuel pump, engine contol mudule (NOTE THOSE)
radiator fan, ac compressor, leak detection pump, air bag module
Many of those items are exactly what is needed to keep the engine running, once it has started.
Have him, or check this yourself if you have a voltmeter or a 12 volt glow light, open the end cap on the far end of driver's side of the dash where is hidden a bunch of fuses and other relays.
Get the engine running then turn the key off and IF the engine continues to run then test for whether or not there is voltage on fuses 13, 14, 21, and 22 in that box. If there is then that is the answer...the ignition switch sub-section that powers those fuses is shorted "closed". To prove that, take out the fuses and verify that one clip of each of the empty fuses sockets shows 12V (I can't tell you exactly which clip, so try both at each fuse). To test for voltage (or with a glow light that you can buy for a dollar or so) touch one lead to any structural shiny metal part nearby, and the other lead to the fuse I listed. If I am right, you simply need a new ignition switch!
My 'vacation' consisted of going a couple of miles from home where my 1975 VW camper van had died by the 'side of the road' on Thursday. Luckily I found the reason in about 5 minutes, it started right up and home we came! I didn't want to get any questions not knowing how long the repair or the tow howm was going to take so I went on 'vacation'. I guess it was a 'mechanic's holiday'.
Roland
---------- FOLLOW-UP ----------
QUESTION: Roland, I failed to mention that the mechanic removed the lead detection pump and is still removed and the car is shutting off now. The thing that is happening is the check engine light stays on.
The mechanic believes that the part is causing some sort of electrical feedback.
Sorry, my son brought this to my attention, hopefully this information is important.
Thanks Roland! :)
AnswerHi Anita,
Somehow a very long answer I wrote got lost:(
Basically I said that the additional information from your son is very relevant and does offer an explanation for why you have had this problem. But I would ask just in case that the mechanic does check the 4 fuses to be sure they don't show voltage in the "off" position, before buying the pump. If is also possible, though unlikely that the wires in the pump plug are shorting out when plugged into the pump rather than that the pump itself is shorted out, so he might want to check that out as well before getting the new pump.
I commend him highly for finding this situation. I suspect he got a clue from a fault code readout. Very interesting and a learning experience for me too. I never suspected that a shorted out pump could cause the engine to not shut down when turned 'off'.
Roland
PS Please 'rate' my answer, if you be so kind again.
