Transmission Control Unit, how to change it out?

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

It would be a good idea to do it. As far as the spark plugs are concerned, I like to put it inside the boot before installing them on the spark plugs.

Let me know if that helps.

Take care,

joe

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Thursday, June 1st, 2023 AT 7:44 PM

MIRIAM BROWN

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18 POSTS

I'm not under the hood. Just asking if I need to grease the TCU three wiring harness plugs that plug into the TCU itself on the driver's side. I wish Ken would have seen this through.

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Thursday, June 1st, 2023 AT 8:18 PM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

Sorry, I read the last few posts wrong. I thought you were asking for both.

Is it required, no. Is it recommended, yes. Anything that will help ensure a good dry connection (inside or outside the vehicle) is a good idea.

Let me know if that helps.

Joe

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Thursday, June 1st, 2023 AT 9:07 PM

MIRIAM BROWN

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18 POSTS

I put the panel back on, started the car, and now the check engine light is back on. Previously, after plugging the unit back in, the light didn't come on after turning it on. Is it safe to drive?

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Friday, June 2nd, 2023 AT 7:23 PM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

Have you rechecked the connector to make sure it is fully seated? As far as safety is concerned, that is a hard question to answer without knowing what turned the light back on.

Is it possible for you to scan the computer again?

Let me know.

Joe

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Friday, June 2nd, 2023 AT 8:12 PM

MIRIAM BROWN

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18 POSTS

Yes, I plan to tomorrow. Also, I didn't ck the connectors since they clicked in, but will ck them tomorrow. I was planning to start moving Sunday but want to do it safely.
Thanks for promptly responding. I still want to know how much dielectric grease to put on the connectors, sincee I'll be unplugging them and plugging them back in.

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Friday, June 2nd, 2023 AT 8:55 PM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

As far as how much dielectric grease to use is concerned, just enough to cover the connector contacts.

Let me know what you find, and I hope you have a safe moving day.

Take care,

Joe

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Saturday, June 3rd, 2023 AT 8:52 PM

MIRIAM BROWN

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18 POSTS

Learned that dielectric grease is not used on TCM connectors. I used the scanner again and it reads that there's a problem with, you guessed, the TCM. Took off the panel, battery cables and called it a night. Tomorrow I'll pull the "plugs" and reinsert them.

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Saturday, June 3rd, 2023 AT 9:15 PM

MIRIAM BROWN

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18 POSTS

Retested the TCU and it still reads problem. Read more online and rechecked the transmission fluid, which was right on, full and red. Do I need to reset the TCU? It clunked just pulling it forward.

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Thursday, June 8th, 2023 AT 2:19 PM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi Mariam, are there specific codes you are getting related to the TCM? If so, let me know what they are.

Also, what clunked when you pulled forward? Do you mean the transmission clinked when placed in drive or did something make noise when you started moving forward?

Joe

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Thursday, June 8th, 2023 AT 8:23 PM

MIRIAM BROWN

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18 POSTS

Just test drove it and it only clunks going into reverse. But now, the speedometer doesn't work.

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Thursday, June 15th, 2023 AT 3:09 PM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

You aren't having too much luck with this. As far as the speedometer, did you do anything with the transmission output speed sensor? Check to make sure it is connected and there is no damage to the wiring. I attached a pic showing it below.

Let me know.

Joe