802SHO 2010 Build

[802SHO]

The copper, yellow/purple, and green/purple wires are part of the 6F55 Transmission Range Sensor (TRS) circuit. The bare copper wire is the drain or shield ground—it has no insulation because it’s designed to ground out electromagnetic interference rather than carry voltage. The yellow/purple wire is the TRS signal return, and the green/purple wire is the signal output to the PCM, both carrying low-voltage logic data that tells the PCM the current gear position; when the foil shielding or drain is compromised, EMI and heat can distort or interrupt those signals, causing the exact intermittent transmission loss and fail-safe condition I’ve been fighting.

I marked in red the portion that is the transmission main harness that plugs into the solenoids in the transmission cover. And the white marks where I’m going to cut open a little more. And redo all of this. The copper wire isn’t shielding anything down here
I’m using a ratchet strap to hold my coolant feed lines and coolant hose to radiator out of the way for more access in this photo

 

[802SHO]

Megatron brought to his knees… not by torque limits, not by broken rods or slipping clutches — but by a few inches of fried foil tape and EMI corruption. That’s the kind of irony only a high-power build can deliver.


What the ffffffffffffffff lmfao

 

[802SHO]

Wow….its it, its the gremlin. I mean aside from looking and explainably the gremlin I have it caught on video. The exact moment TRS loses valid signal and then the transmission enters fail safe. Neutral.

I did 3 lift tests. When I was going through relays, fuses and grounds.
Test 1) Manual 1. Fail. No video
Test 2) Drive. Fail. Video recording
Test 3) Manual 2nd. Fail. Video recording

Test 3 the last drive test before finding this missing foil. My wheel speed in 2nd manual is maintained up until the TRS signal is totally skewed from EMI, it falls out of rotation speed and almost stops….keeps going a little more at much slower rotation briefly and then neutral.

This is a case closed gentlemen. I know I cringe at not validating first but cmon. I’ll update after work when this repair happens and follow up results

 

[802SHO]

I told Chuck I wiggled this once before during test 1 and I asked if it’s bc of EMI it didn’t make a difference and he said Bingo! The wire integrity and connections are solid,
So wiggling didn’t make a change bc it wasn’t the problem, it was the EMI barrier (foil tape) missing and EMI won.

 

[FrankK]

Thank you for being persistent.

Keeping fingers crossed this is it.

 

[luigisho]

I never had that much persistence with electrical to get that far in and figure out something that elusive. Tip of the cap

 

[802SHO]

Wrapped the wires
Added DEI high heat loom
I set up my phone, pressed video record and started him up.

longest time to beat about 11.5 min.

12min….
13min…

I’m talking to it. Cmon that’s what I’m talking about! Show them who you are. Time to rip man! Let’s go!

14 min…..WOW! No hesitation it’s just going

Stefanie is now intervening bc it’s 9:04….:her strict 9pm sharp bedtime. Like r u f kidding me? Like it means nothing meanwhile this means EVERYTHING to me.

I had worked late, I came home to an empty propane tank, just it’s passed 7:15 and I’m starting my foil tape job.

I go to shut it down….hmmm I should downshift into 1st, then brake and park. I get on my lift and downshift into 1st. Wheel speed slows down….then stops! I was in my victory stage….i cycled the gear selector a bunch couldn’t get it back.

I’m about to abort and I think…I’ve never done a how long does it last the second time test. I start it back up. Now I’ve got it in 1st, second…back to 1st…it’s good. I’m 5 min in…..and here she comes ….ok fine and this time I shut it down. Normally my working window after first fail on the road is 1-2 min working time. I went 5+ and I stopped it. It wants to work. Idk guys it didn’t go like I had hoped but this is new and good. Idk I think it needs a road test.

 

[Zpak]

Road test!

 

[802SHO]

Tested again after adding foil around the suspect sections of the harness and grounding that new foil to the battery negative. The DEI sleeve was kept in place over it. Manual mode worked right away, though the gear didn’t show at first until I cycled to park and back. About five minutes in I hit the brake, went to park and back to drive, and it reengaged perfectly. The fan was turned on at eight minutes and it kept running smooth. Around 17 minutes it hesitated slightly but recovered on its own. A little past 18 minutes I hit the brake, put it in park, and that’s when it finally dropped out.

So the added foil shielding and ground may have improved stability and signal quality but it’s hard to know for certain bc last night the GF intervened. It lasted longer than before and stayed unaffected by fan load. The next step is to ground the foil closer to the transmission or block instead of battery negative and see if that eliminates the small drop when shifting or braking.

 

[802SHO]

I’m going to buy some RFI sleeve from DEI. Do more tests and likely end up opening up the splice from transmission to range sensor. I said I was going to cut it open more but decided not to….yet.

Here’s my oil report. Looks pretty damn good. Expected to see more aluminum but should see a drastic drop in future samples. Looks like a healthy break in.

 

[802SHO]

Ryan Martin sent me a base map. Why not….flashed back to stock. Loaded the tune. All modules are back online. Started to wonder if Brad turned off a global switch and communication chain got broken.

Idle great. Took a log in HP, love the gauges and layout way better. Saved a 6 min idle and put it in gear.

This static lift test is way better now. If I don’t touch it it wants to keep going the distance. So I mess with it and I can get it to stop.

But Ryan wanted me to get a list of DTC’s. I pull them, after 3 tests. I logged the first transmission fail for him to hopefully look at.

We have a new player on the DTC list. P1602 Immobolizer/ECM Communication Error. Focus is shifting now

 

[Texas Marauder]

May not be a big deal. From the service manual:

DTC P1602 (Immobilizer/ECM Communication Error) — sets in continuous memory when the PCM does not receive any recent communication from the PATS module. On this vehicle, the PATS function is contained in the IPC. A parameter reset should resolve this DTC.

FOScan calls this "Module Initialization".

Also, PATS will only prevent the car from starting. IMO, once started, PATS is out of the picture.

 

[802SHO]

Interesting though that Pats is even on the map. I found out about Pats when I removed my sunroof motor and the harness up there. Couldn’t start the car. I reinstalled the harness and zip tied it bundled up where the headliner used to be.

Started the car back up. That was back in July. So idk why anything would point back to it now

 

[802SHO]

The female terminals 1 and 2 for Relay 65 have a little play. Possible issue from it

Coil Pin	Function	What Happens if Loose
1	Ignition ON / PCM command	Relay never energizes or intermittently energizes
2	Ground / return	Same effect -relay opens randomly

 

[802SHO]

Going to buy a back probe kit from Harbor Freight today.

 

[luigisho]

Going to buy a back probe kit

My biggest nightmare. I'm glad to watch you tackle this though. At this point I set it on fire or give it away

 

[Zpak]

My biggest nightmare. I'm glad to watch you tackle this though. At this point I set it on fire or give it away

I’ve been troubleshooting this ’93 for like two days and feel the same.
Major props to you Andrew.

 

[802SHO]

Ok I bought some new tools. Made a discovery. Fuse 38 female terminals were loose, intermittent green light, found loose female terminals also 5A fuse dark color stains. Bent terminals inward, new fuse and little dielectric grease solid reading. This was PCM logic/sensor reference feed.

Next up the passenger strut tower ground…badd
All fixed up and verified solid as a rock
Now it’s passed 9pm….cant test until tomorrow. This is big though. 2 solid rotten apples fixed

 

[Zpak]

Ok I bought some new tools. Made a discovery. Fuse 38 female terminals were loose, intermittent green light, found loose female terminals also 5A fuse dark color stains. Bent terminals inward, new fuse and little dielectric grease solid reading. This was PCM logic/sensor reference feed.

Next up the passenger strut tower ground…baddView attachment 95980
All fixed up and verified solid as a rock View attachment 95981
Now it’s passed 9pm….cant test until tomorrow. This is big though. 2 solid rotten apples fixed

Yeah that strut tower one on both mine were all chewed up from all the on and off’s with the catch can.

 

[802SHO]

Man I’m pumped! I went to Harbor Freight and bought the Power Probe III, back probe kit, also a cheap test bulb one and a cool magnetic LED light.

I was just tooling around with it to get used to it and was testing ignition off and on and found these. It was such a better tool than the multi meter where I was trying to hold it on battery - and touch it to the passenger strut ground. I knew I should have cleaned it and idk you guys I just didn’t….until now