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Dogbert62

Replaced PCM twice in 500 miles? What kills PCMs?

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All,

 

Have a 2017 Connect with 6k miles.  The van shut down and would not even turn over the starter..  Just flashed a bunch of warning lights..  Dealer replaced the PCM.  300 miles later.. the same thing.  So, either the van had a faulty PCM and the dealer replaced it with another faulty PCM (skeptical), or something is killing the PCM and I will likely get stranded again.. The service advisors in both instances said that the diagnostics pointed to a bad PCM..

 

So..  what can kill a PCM??  my myopic view is nothing since it has burned firmware that theoretically can't change. It also kills the car.  So, it isn't like the PCM overheats and starts the car later... it is dead other than throwing a bunch of sensor type errors and finally telling me I have a powertrain fault (dont remember the verbiage).  With all this said, it seems highly unlikely that I would have two catastrophic PCM failures in 6k miles 

 

Regards

Dogbert

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I seriously doubt it's the PCM ... I'd be looking for either a short or other problem with the harness. Maybe even just a dirty connection. 

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Never head of this with any TC.

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I can understand a simple "code says" replacement the first time but a second identical failure in such a short period should have caused the second repair to involve additional checks and troubleshooting to eliminate other causes besides a bad PCM prior to replacing it again.

 

If the problem persists and isn't corrected, you may need to invoke your lemon law protections. Here in Texas the rule is 4 repairs for the same defect in 24 months / 24,000 miles, but I am sure each state is different.

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Electrical operation, although not as complex as most people think, is vastly misunderstood.

First thing ... a short-to-ground fault happens before the "load" (whatever component is being powered) and therefore does not effect the load.  A short-to-ground cannot cause a failure of your PCM.   The other fault generally blamed for destroying components, and open circuit ... also doesn't destroy anything.  A switch is a designed in circuit fault and you don't destroy components turning things off and on.

Electronic components can be destroyed by either of those faults ... but not directly.  Intermittent faults, the switching on and off rapidly of a component can kill electronics.  So, if you go looking for circuit problems, you're looking for an intermittent one ... which is very hard to trace out.  If you're lucky, you'll see a corroded connector, or a wire with the insulation rubbed off.

 

The most common reason for computer failures in a car is a bad regulator on the alternator.  They keep the voltage on the battery at a maximum of 14.7 VDC.  If they are going bad, you'll see spikes exceeding 15 volts.  A few of those can wreak havoc on a circuit board.

 

It IS possible to get bad components ... and perhaps you'll get lucky with the newest install.  Too many times, though, mechanics replace damaged parts without going the necessary step further and discovering the cause of the damage.

 

Good luck.

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I agree with Mike  The system voltage needs to be recorded over time with a scanner to see if the alternator is spiking the voltage,  The battery  should be tested also  a bad cell could also cause a voltage spike .

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Thank you everyone for your responses...  Although I was hoping that the consensus would be that I got a bad replacement PCM, the tenor of the responses say that it is likely something else. So, let me explain my saga a bit further..

 

The first repair was just over three weeks here in Austin, They replaced the PCM and battery. When I got the car back, there was a circuit tester on the passenger floor so I *assume* they were worried about some of the voltages.  . 

 

Since this is my grand-baby hauler, I went on a couple break-in hill country drives when it crapped out the second time..  The nearest dealer was in Kerrville.  While sitting in the lobby, I at least got the feeling that their shop want near as hectic as the one in Austin..

 

About two weeks in, the service advisor said that they were still scratching their heads. He said that they have a Ford expert come in once a month to help them with the tough issues; mine being one of them..  Just got the van back and have put ~300 miles on it without issues.  Their report is a bit more detailed.

First they replaced the PCM and battery tray.  I guess the Austin dealer broke the battery tray when they replaced my 6k mile battery with their house battery..

It also looks like the PCM power on pin 20 was only 10v.  They traced it back to a loose connection on the bottom of the fuse box on the downstream side of Fuse 32.  Crossing their work with the manual suggest that Fuse 32 is the 15A fuse that is one of two that power the Engine Control Module.  Since there are two fuses, I can see how a bad voltage on one could kill the PCM.  They also said that a fuse was blown..  Not sure if it was one of the two control module fuses though..

 

Looks like they did a few EEC system diagnosis (quick test) during the debug as well.

 

Got the van back in 4.5 weeks

 

Any thoughts on whether I have put my issues behind me?  Again, thanks for the help

 

Dogbert..

 

 

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It sounds like the second dealer is doing a better job, and that is where I would bring my vehicle back to for further service.  And since they know of your PCM issue, they could probably do a better job with keeping an eye on it for you.

 

Rewind this back.

15 hours ago, Dogbert62 said:

 

 

the Austin dealer broke the battery tray when they replaced my 6k mile battery with their house battery..

 

 

 

 

 

I've never heard of something like that.  A car dealer took the OEM battery out, and replaced it with another battery, prior to selling you the car.  Why?  Was this something that they did prior to selling the car to you?  That sounds fraudulent.  There is absolutely no reason to replace an OEM anything, with something else, then sell the car.  Are they taking your Motorcraft battery to resell as new to another customer?  Are they selling you a new car, with a low quality battery?  If you are buying a new car, you have every expectation to receive a new car as it was built at the factory.  What other parts are they stripping from their new cars?  Check your tires.  Are those OEM tires, or $40 tires from China?  

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Fifty150,

 

The first dealer will never see my business again.  I have also expressed my concerns with Ford. 

 

With regards to the battery, it is likely that their house battery will last nearly as long as a new one. It is a consumable... Besides, would take your vehicle back to them to replace it?  Not me...  I prefer to chalk it up to experience an move on with the hopes that Ford slaps the back of their hand real hard.

 

Back to the van's issue...  

I haul grand-babies in my transit connect ranging from 6-months to 8-yrs old.  I can handle a most issues since I can limp my van back to my house.  However, having the van cut out on the highway and not restart..... in 105deg Texas heat.... with a 6-month old and 2-yr old special needs child is not something I can handle. 

 

My original post was put up before I went through the service documents from both dealers.  Additionally, the responses made sense.. especially the ones that talked about voltage regulation.  If I were to guess, the first dealer noticed the low voltage on the PCM pins and replaced the battery.  When they went back to check, the voltage was back up to 12v since it was a flaky connection so they though they had a bad battery and the problem was fixed.  It was the second dealer that noticed the flakiness and chased the problem differently.  

 

The nagging question is whether a flaky voltage on one of the many power pins to the PCM could in fact kill it.  It seems plausible but car companies are required to make their mission critical components as bullet proof as possible..  I would hate to to declare and "all clear" when in fact there is another root cause that may rear it's ugly head.... again..
 

 

Thanks again all for your help...

Dogbert

 

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Absolutely  The low voltage made the circuit take more Amps to do the same job.  If the connection was loose or intermittent it could result in a voltage spike that could harm the Pcm.

The critical components are generally well engineered . Bad assembly or a failed  component can undo good engineering.

Keep us up dated   Safe travels!!

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I used to be a Master Tech at a BMW dealership and now I'm an electrical engineer so I'll give it my best guess what happened.  It sounds like dealership one poorly diagnosed the problem and the true failure was intermittent.  The PCM relay is controlled by the PCM and supplies power to the PMC. I think F32 powers this relay and it will cause weird problems that might point to a defective PCM and if it is a loose connection will be intermittent.  

I dont think you will have a problem anymore but if you do get rid of as a lemon, 4.5 weeks in a shop is long enough in most states.  But if you're happy with it make sure to not take it easy and complain, at BMW we would have made lease or loan payments on a car if it was in a shop for more than a couple weeks

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You would think that on an issue like that, where it is apparent that the malfunction was not caused by the customer, any reputable dealer would assist with deferring your payment and/or provide a loaner.  

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All,

 

Thanks again for your help and info..  I have looked into the TX lemon laws and it looks like the closest version to my tale is the 30day rule.  The bottom line is that if I have another issue with the PCM before January, I can invoke the lemon law.  As you can imagine, I have soured on Ford and have looked into alternatives that fit my wants and needs...  Well, the best vehicle I can find is the Transit connect.  Add to this the fact that the TC seems to be a fairly reliable commercial platform, I would likely replace it with an exact copy of the TC that I have.  

On the time to fix and loaner...  I have another vehicle and didn't need the TC as a daily driver.  So, allowing the dealer to work it and not require a loaner was not a big issue.  in hindsight, it may have lit a fire under their back side if they had a financial impact for taking a long time performing warranty  work on a vehicle that they didn't sell, but that is water under the bridge. 

 

The bottom line is that there is seems to be some confidence on this forum that they flaky voltage on pin 20 may be the smoking gun..  If it isn't, i will be shopping for a replacement on Fords nickel..

 

Dinocarsfast....  I chuckled when you said you were a BMW guy....  I sold my 2001 BMW 330CIC convertible with very low miles to make room for my grandbaby swagger wagon...  :)

 

I passed 500miles.... So I have my fingers crossed

 

Regards

Dogbert

 

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You didn't consider a little more luxury, like a Honda or Toyota van, for driving kids around?

 

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😝  The way I feel about kids ... I'd have them in an open bed trailer on the back of my vehicle.

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Here we go again.

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What!?  😃

The trailer's better than the alternative ... put 'em on a leash and make 'em run beside the car!

Either way, they aren't IN my vehicle !!!

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Now Now! Lets no get carried away.

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16 hours ago, Mike Chell said:

What!?  😃

The trailer's better than the alternative ... put 'em on a leash and make 'em run beside the car!

 

 

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Now we are way off topic.

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I do believe the topic was over on dogbert's last post, and he's satisfied with his repairs now.

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Right at 1k miles since the last fix...  Likely out of the woods  

 

Why the TC and not a true swagger wagon?  A ton of reasons

1) I have a 6 yr old and an 8yr old set of grandkids that Dad wants in 5-point harnesses.  The Chicco car seats hit the roof in most of the standard swagger wagons but the TC is extra tall

2) I hate to put money into depreciating assets like cars... Especially a kid hauler...

3) I have a 2.5 yr old  grandchild that may never walk that even Mike would fall on love with.  The low seat height and high roof is much easier to sling her into the massive rear facing car seat than the Tahoe and Suburban that Mom and Dad have.

4) The TC can be easily retro-fitted for wheelchairs... I got the cargo doors and not the lift gate

5) I take loooong camping trips so good gas mileage is important

6) The seats fold flat nicely such that I can crash in the back on a long trip

7) I may be weird, but I like the looks of the TC much more than the classic swagger wagon..

 

My mid sized 2006 truck is getting long in the tooth so I was originally looking for a utilitarian van with good gas mileage that I could build out for camping..  So, I was looking at the little cargo vans like the TC.  I liked the TC the best.. When it became probable/possible that I would need a wheelchair capable rig, the TC wagon was almost a no-brainer.  

 

Mike....  I'll take grandkids over pets...  The Lampoon  video posted above in this thread is one of my favorites...

 

Dogbert

 

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4 hours ago, Dogbert62 said:

 

 

.  I liked the TC the best.. When it became probable/possible that I would need a wheelchair capable rig,

 

 

 

 

 

The wheelchair ramp conversions are already on the road.  I see them out there in use.  

 

I still wonder about passenger safety, when a wheel chair is rolled into a van, then strapped down.  Okay, the chair is safe.  What about the person in the chair?  Is that wheelchair position in a correct position to work with the vehicle's airbags?  I still think that if possible, it is better to assist the person into a vehicle, strapped in with the vehicle's seat belt, and in the correct passenger position for the airbags.  At least that is how I've been doing it.  But I'm not in the business of transporting the disabled.  Just driving around family members.

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On 7/29/2018 at 7:48 PM, Dogbert62 said:

 

 

 

4) The TC can be easily retro-fitted for wheelchairs... I got the cargo doors and not the lift gate

 

 

 

 

 

 

Here is a conversion that I saw on the road today.  It was done with the lift gate.  This style is completely manual.  No electronics or hydraulics to flip or position the ramp.  You have to physically push the chair up the ramp and into the vehicle.  But I think there are a few different options available for design and configuration.

 

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