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Pete
Pete, Auto Service Technician
Category: Ford
Satisfied Customers: 24659
Experience:  Over 17 years diagnosing and repairing automobiles various makes and models with some training and certifications.
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Pulling several transmission related codes. Lincoln town car

Customer Question

Pulling several transmission related codes. Lincoln town car feels like it's starting off in second gear or third gear with little power. It shifts one time while accelerating and then will not shift into overdrive. Overdrive light is flashing. Vehicle was running good until we started swapping relays in the battery junction box. We pulled the battery junction fuse panel and jumped a wire from the horn fuse to the horn relay. Not sure if this is a coincidence or if we messed something up electrically in the fuse box related to the transmission please help. Here are some of the codes. 2003 Lincoln town car 4.6 L engine
Submitted: 8 months ago.
Category: Ford
Expert:  Pete replied 8 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

Did you make sure you reinstalled the relays all in their proper places and correct positions?

Let me know so we can continue from here.Thanks Pete

Customer: replied 8 months ago.
are there any relays in this box that could cause a problem with the transmission? Maybe one of them is defective and I should swap a couple around.
Expert:  Pete replied 8 months ago.

Yes,the PCM power relay.It controls transmission electronics and sounds like it is damaged or incorrectly installed or is the incorrect part number relay.This can also damage the engine computer (PCM) itself if the wrong part number relay was installed or is installed incorrectly.

https://www.dropbox.com/s/gpx1hegz0rfx46a/pcm-03-28.gif?dl=0

As you can see here it controls the transmission sensors and solenoids

https://www.dropbox.com/s/41qkzoeb6jquf39/transf-03-28.gif?dl=0

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 8 months ago.
About seven of the relays are the same relays in that junction box and all the part numbers are the same. I swapped relays and there is no change. We checked all wires and wires look good. We disconnected the positive and negative and touch them together for five minutes to drain everything the overdrive light is still flashing and it's stuck in 3rd gear it feels
Expert:  Pete replied 8 months ago.

Was any of this an issue before you started to pull and swap relays at all?

Customer: replied 8 months ago.
No it was not . We swapped around a bunch of relays trying to get the horn working which is right next to the PCM relay. While troubleshooting the horn relay we didn't have power on number two and number three on the relay and both of those locations get power from the horn fuse. So we jumped a wire from the horn fuse to number three on the horn relay and made the horn work and then this problem started. We reverted all wiring back to original. I replaced the PCM relay. Disconnected the battery terminals and touch them together to reset the PCM and transmission computer an the overdrive light is still flashing and the vehicle feels like it's stuck in third gear with no power when accelerating
Expert:  Pete replied 8 months ago.

And you double checked to make sure ALL fuses are o.k. am I correct?

Customer: replied 8 months ago.
I replaced the relay to the PCM computer
Expert:  Pete replied 8 months ago.

I am wondering if the swapping of the relays has damaged the PCM itself.I have seen this occur before if a voltage surge had occurred which is very possible when the relays were swapped around.With what is occuring here and what has been checked and done this sounds like what has occurred with it needing replaced and programmed.The programming has to be done by a dealer with their computer plugged into your vehicle once it is replaced.

Let me know if you need anything else and feel free to rate my help here.

Thanks Pete

Customer: replied 8 months ago.
I was thinking the same thing. We disconnected the main terminal going to the fuse box and didn't disconnect the battery the power searched the bunch which was stupid. Can we get a junkyard computer and put it in direct replacement? Does it have to be programmed?
Expert:  Pete replied 8 months ago.

You can do this as long as it is from the same year and model,same part number with same engine and transmission as well as same emissions (California or federal emissions).You may have to have a dealer reprogram the theft system in it but it should install and work if from the same model.

Thanks Pete

Customer: replied 8 months ago.
If I get the correct computer will I be able to install it and test it or will I have to tow it to the dealer to D activate the security system? I'm wondering if it might be safer to replace it in the Dealer parking lot is what I'm getting at
Customer: replied 8 months ago.
Can you send the diagram for the location of the computer so I can get the numbers and call the salvage yard with the numbers please? Thank you
Expert:  Pete replied 8 months ago.

It would be best if it was at the dealer when it is replaced so they can program it for you.They will probably double check the complete programming in it to make sure its all o.k. but wont charge extra for that.It is located under the hood on the drivers side as seen here against the firewall.

https://www.dropbox.com/s/hcgi5f0sddtc4nx/ecm-03-30.gif?dl=0

The part number I show is 3W1Z12A650ARA.You might double check this number with a dealers parts department over the phone to see if there is any updated number or any older compatible numbers so you have all numbers that will work when looking for a used one.One place I use for used parts is http://www.car-part.com.They can ship to your door for you.

Let me know if you need anything else and feel free to rate my help here.

Thanks Pete

Customer: replied 8 months ago.
Gonna replace PCM
Expert:  Pete replied 8 months ago.

O.k.,let me know how this turns out here.

Thanks Pete