My 90 year old mother-in-law is still driving her 2004 Buick LaCrosse with the 3.8L V6,but now is afraid to drive it. At least 4-5 times while driving over the past year the engine just dies and the car has to coast to a stop. Sometimes it will restart and other times it has to set for some time before restarting. Mechanic said problem was traced to bad battery terminals so replaced them. Problem happened again. Since I don’t live near her I suggested her son send me any pertinent information on it. Showed me a photo of the fuse box under the hood and it did show some heat related scorching near the #14 and #15 relays. Since I believe #15 is related to the ignition I suggested he switch out or replace it and see what happened. No change. Car died while he was driving it later. Many repair blogs state various fixes, but many state problem recurred after those fixes. They have suggested, crank position sensor, fuel pressure regulator, MAF sensor, ignition switch replacement, checking all grounds and looking for frayed wiring going thru the firewall, ECM replacement, etc., but before throwing a lot of money toward questionable fixes I wonder if anyone out there has seen this problem and have gotten a good and permanent fix. My mother in law is obviously on a fixed budget and repairs that do nothing is not an option. This appears to have been a problem with GM cars for some time so they don’t seem to have found any particular fix either. HELP!
I would suspect the Crankshaft Position Sensor.
The crank sensor is one of the primary inputs into the computer.
One the purposes of the crank sensor besides detecting for misfires is, it informs the computer whether or not the engine is rotating.
if the computer loses the signal from the crank sensor, the computer thinks the engine is no longer rotating. So the computer see’s no reason to operate the fuel and ignition systems. And the engine shuts off.
And a faulty crank sensor doesn’t always turn on the Check Engine light. Which makes it hard to diagnose.
It sounds what mechanics call a “heat soak” problem . Something is getting too hot and failing . The crank position sensor idea posted above is a good place to start, as that’s a known part associated with heat soak. You can either have it tested or just try replacing it.
If that doesn’t solve the problem you’ve got to narrow it down to either spark or fuel problem. If I had that problem I wire a volt meter to the fuel pump and monitor it as I drive. If the voltage drops coincidentally with the car stalling, I’m thinking it is a fuel pump power supply problem, either a faulty connector or relay probably. It’s also possible to outfit the car with a fuel pressure gauge, same idea. The ignition system can be tested by visual inspection and an o’scope ignition analyzer. Intermittent like that can prove to be very diffiuclt to figure out. Cars are very complicated these days. One idea, ask the local shop there if they’d be willing to take the car and use it as a daily driver among their shop staff. Eventually it will fail and the shop staff should be able to figure out the problem at that point.
My first guess is crankshaft position sensor
When it fails, it’s game over. If you’re driving, the engine will stall. If you’re trying to start, it won’t. Sometimes it’ll behave again, when it cools down, but this is temporary.
And worst of all, this kind of problem often generates no kind of fault codes, whatsoever.
It takes a rather sharp mechanic to catch one that’s failing, without generating a code
As for that fuse box, all I can say is that had melted, due to electrical problems, but the problems they caused were not intermittent in nature.
Just out of curiosity, why is it that you seem to have taken the lead on this problem, versus the son? It sounds like he lives closer to her . . .
A word of advice, there ARE some bad apples out there that will see when they see here showing up at the shop, and might try to sell here stuff which she doesn’t need, and won’t take care of the problem(s). It happened to my grandmother when she was in her later years. I wasn’t living anywhere near her, and wasn’t in a position to help, anyways. I found out about it later. If/when she does take the car to a reputable shop . . . avoid the big name franchises . . . don’t let her show up alone. Preferably, have somebody accompany her that is somewhat familiar with cars. It might lessen the chances of her getting played
Thanks for your reply. My brother in law is going to take the car in to have the crankshaft position sensor replaced and hopefully that will take care of the problem. I have been helping him with trouble shooting and researching solutions because he is very busy with work and family issues right now so I’m just helping him out with that angle. We have talked about, and he is very aware, of repair places that just throw parts and labor at a car issue. The fuse box issue wasn’t an actual melt down, but a relay that went bad and overheated thus causing the “sooty” burned marks on the fuse box that looked worse than it was. We never have his mother take the car in for service or repairs alone and I think she is not too far away from not being able or comfortable in driving too far anyway.Again, thanks for your input and concerns.
Wow, your in-laws seem to have a full plate
Good luck with the repairs, and please let us know the outcome
Well my brother in law had both the crank and cam shaft sensors replaced on his mother’s 2006 Buick Lacrosse that has been intermittently dying for over 6 months now. Many blogs stated that that might be the problem so we went that way. Result - no change in the dying symptoms. I had originally suggested he replace the #15 relay in the fuse box and he swapped one of the same type in there with no difference in the dying problem so we moved on. Yesterday he decided to finally replace the #15 relay with a new one and then drove the car hard and hot and no dying problems. He then put the old relay back in and drove the car - the car died several times. He replaced the #15 relay with the new one and drove the car hard again. No dying! So now he hopes that was the problem all along.
Replaced the crank and camshaft sensors and dying of car still happened. Replaced the #15 ignition relay in the fuse box and no dying. Tried the old relay again - car died. Put the new relay back in and no problems. so hopefully that #15 relay that I had wanted my brother-in-law to replace the first time turns out to be the simple and final fix. Go figure.
Thanks for the update. Fingers crossed on your behalf!
Just curious: what names does the fuse box give for the 14 and 15 relays’ functions?
I was in error earlier when I said my brother-in-law replaced the #15 relay. He replaced the #44 relay which originally showed some heat warping. The strange thing is that this relay controls the high speed wiper function. On the relay box schematic it shows a number 13, 14 and 15 line pointing to this relay also and I can’t find out exactly what that means. Maybe this means that the #13, 14 and 15 fuses have some connection with this relay circuit for some reason and I do know that the #15 fuse is in the PCM circuit and thus somehow was related to the engine shut down problems this car is experiencing. Car is running fine so far with this #44 relay change out. Wish I knew why.
If a relay swap out fixes the problem, my guess would have been the fuel pump relay. I’ve experience that problem on a VW Rabbit before.
I tried looking up the schematics for your 2004 Buick Lacrosse but I don’t see that model listed for 2004. For the LeSabre number 44 seems to be a fuse for the ABS module.
Thanks for the reply. If I stated the Buick was a 2004 that is my error. It is a 2006 Buick Lacrosse. The car would not “crank” or turn over at all after it died so don’t suspect the fuel pump relay or system at all. The relay we replaced that seems to have corrected the engine dying problems is the #44 relay that says it is for the high speed wiper function. This is totally crazy as we reinstalled to old #44 relay and the car died several times again and after putting the new #44 relay back in the car has run fine ever since. I cannot find any reference as to whether any other wiring function is associated with this relay other than an online fuse box diagram of this cars fuse box I downloaded that has numbers 13, 14, and 15 with lines running from those numbers to the #44 relay. Do these correspond to some function/wiring connection from fuses numbered 13, 14, or 15 or some other reference to these numbers being connected to relay #44? I don’t know, but I do know that this relay replacement appears to have solved the numerous engine dying problems on this car! We could have followed some mechanics advice and spent $1700 dollars on suggested unwarranted repairs for a new throttle body and PCM computer, but did spend $350+ repair for the crank and cam shaft sensors we did replace that did not fix the problem. The fuse box shows heat discoloration to a number of the various relays on this car and we may replace most of them if the car continues to run okay just to make sure no more of them fail at some point in time.
Take a look at your title And what you said in the original post
I looked it up for the 2006 Lacross V6 3.8L vin 2, and you are right, relay 44 is for the windshield wiper “hi” function. The circuit seems to go like this: Battery power is sourced through fuse 5 (25 A) . When wiper relay 45 turns on (wipers on mode), it switches battery power to wiper relay Hi 44. Relay 44 either sends the battery power to the hi or low terminal on the wiper motor, depending on which mode the driver sets. The two relay’s magnetizing coils are controlled by outputs from the body control module.
I can’t see any way that relay 44 would affect other parts of the electrical system, but there is a failure mode for relay 45 that could cuase the battery power to short to ground. You’d think that would blow fuse 5, but perhaps it is shorting battery power to ground very briefly, causing a glitch that’s upsetting the ignition system or something. If the ww motor was faulty, that could cause the same problem. There is a recall on the motor, have you had that done ?
Besides replacing relay 44, suggest to verify w/the dealer the the ww motor recall work is complete, and probably replace relay 45 if you haven’t already done so. Visually check the condition of fuse 5 too. If that doesn’t solve it, you’ll probably have to replace the entire relay box. There is circuity in that box that powers the ignition system and fuel pump. Re: Recall 15789, 10.26.2015.
Well, back to square one with the 2006 Buick Lacrosse engine dying problem. Thought we had it fixed, but car died three more times again today. #37 relay was very hot so switched it with the #39 relay and car died again. All these relays were replaced two days before this incident anyway. Next suggestions are to replace the ignition switch or the ignition control module under the coils. Hate to keep throwing parts at it, but that is what dealer or other mechanics will do since no one can diagnose the exact problem. Only warning code showing up on the dash is the “starting disabled” warning under the speedometer. Car will restart after a few or number of minutes after dying, but may fail within a few minutes to several days afterwards. Can’t believe GM keeps saying they have not run into this issue before when so many Buick 3800 owners have similar issues over a wide year range of these cars. Very frustrating and dangerous condition, especially if the 90 year old owner is driving it!
March 16 |
Mrfish:If I stated the Buick was a 2004 that is my error. It is a 2006 Buick Lacrosse.
Take a look at your title And what you said in the original post I looked it up for the 2006 Lacross V6 3.8L vin 2, and you are right, relay 44 is for the windshield wiper “hi” function. The circuit seems to go like this: Battery power is sourced through fuse 5 (25 A) . When wiper relay 45 turns on (wipers on mode), it switches battery power to wiper relay Hi 44. Relay 44 either sends the battery power to the hi or low terminal on the wiper motor, depending on which mode the driver sets. The two relay’s magnetizing coils are controlled by outputs from the body control module.I can’t see any way that relay 44 would affect other parts of the electrical system, but there is a failure mode for relay 45 that could cuase the battery power to short to ground. You’d think that would blow fuse 5, but perhaps it is shorting battery power to ground very briefly, causing a glitch that’s upsetting the ignition system or something. If the ww motor was faulty, that could cause the same problem. There is a recall on the motor, have you had that done ?Besides replacing relay 44, suggest to verify w/the dealer the the ww motor recall work is complete, and probably replace relay 45 if you haven’t already done so. Visually check the condition of fuse 5 too. If that doesn’t solve it, you’ll probably have to replace the entire relay box. There is circuity in that box that powers the ignition system. Re: Recall 15789, 10.26.2015. Visit Topic or reply to this email to respond.
In Reply To
March 15 |
George_San_Jose1, Thanks for the reply. If I stated the Buick was a 2004 that is my error. It is a 2006 Buick Lacrosse. The car would not “crank” or turn over at all after it died so don’t suspect the fuel pump relay or system at all. The relay we replaced that seems to have corrected the engin… Visit Topic or reply to this email to respond. To unsubscribe from these emails, click here.
I think you probably have an over-current condition that has damaged the relay/fuse box internals. Could be the ignition module, ignition switch, WW wiper motor, or the fuel pump circuitry, but that’s just a guess. If you could get it to fail while it was at the shop, an experienced auto-electrical tech should be able to at least identify which circuit is causing the problem. Make sure there are no fuses having larger current capability than they should; i.e. if the fuse is supposed to be 10 amps, make sure someone hasn’t put in a 15 amp. That tends to happen sometimes when intermittent electrical problems b/c frustrating to solve. That method usually causes more trouble than it solves, including car fires. .
Thanks for the advice and I will pass it on to my brother-in-law who has been dealing directly with this and was driving the car today when it began acting up again.
I wonder how much a recycled fuse/relay box from a wrecked version of the same make/model/year with all the relays and fuses included from a junkyard would cost? I’m thinking less than $100. Suggest to surf over to the pick and pull website, from that you can check what parts cars they currently have on site at the nearest p&p locations.
You have a tough problem here to try and fix. Intermittent problems are bad enough by themselves and you are trying to do fixes remotely on top of that. When working on this type of problem it really helps to have all the clues you can think of to help solve the problem. Like, do the dash warnings lights turn on when the trouble occurs, do any of the accessories work or go out at the time the trouble happens? Checking things that require power, to help verify where power is or isn’t getting to when the trouble is occurring. These are very helpful clues to help guide you to the trouble. Having a factory wiring manual to guide you is worth its’ weight in silver for these kind of problems. I wouldn’t invest in anymore parts until you have one of these. Ebay is a good place to get one.
The trouble you describe does sound like a relay problem for sure but the problem could just be a bad power wire connection also. It does seem to be a power delivery problem anyways. The data I have to look at shows IGN RELAY 1 supplies power to the ECM, PCM, and the engine start relay. Perhaps that is where the code is coming from when the power drops off. If that IGN relay hasn’t been replaced yet then I suggest you try swapping it with another if you can.
The ignition switch is supplied power from the BCM so if the module has a problem that may be where the trouble is at. Testing should be done to prove that. But again, the trouble could be just simply be bad wire connection. By adding small LED lights to suspected key trouble points for power, where you can see them when the trouble happens, may help you pinpoint the problem area.
My brother in law finally had run out of time a patience with this car so he took it to the dealer and it failed on them and showed it needed a new PCM. So $1000 later we hope that the car, mainly used by his 90 year old mother will not fail again on her. So far running okay.