1991 xj6 trans fault after i washed it

2nd and third only i pulled the pass side trim away and found water around ecu

Welcome to the forum Arlan, thats a strange condition, these normally fault to 3rd gear and reverse (limp home mode)
Have you tried drying the ECU to see if that helps?

opened the pass side under glove box to allow air flow as well as spraying w=d40 i will give it some time to work thanks for the response nice to have an area to voice woes take care and be safe

found water in heater box drained it put a fan in there hope the ecu survives

all good problem solved after drying ecu thank you

it was all good till i got yo the end of my driveway lite came on im drying it some more hope that works thanks

Dying at end of driveway certainly indicates an electrical issue… seem you are on the right track… if additional drying does not work… check the cleanliness of the ECU behind glove box see how clean they are and wire harness connector plug for any oxidation or damage… I have an 89 the ECU inside was conformal coated plastic coating protects parts from moisture… my suspicion would be the ECU connector… anywhere you have discovered water… examine nearby connectors…
Good luck… intermittent problems can be frustrating to find even for PRO mechanics

cleaned dry and connected still has light ordered a used replacement hope that its good are thier any fuses that play into this issue?thank you
in advance the light stays on now after flooding with wd40 might not have been a good idea then got electrical spray dryer and air to further clean the connecters light is on maddening it is take care and be safe

Light for transmission fault or?? I dont think any circuit board fuses were inside the ECU…
Did you look inside the ECU connector to see if it still looks clean best would be looks shiny?
Transmission issues could be solenoids again are the connectors clean wires in good shape not abraded melted, age cracked etc…
engine dying abruptly is most likely electrical

if you swap the ECU and same symptoms appear than you know it is not the ECU and you have a spare…
would be great if you could monitor the power to amplifier, coil, and ECU and see it die but that’s hard to set up with many meters or LED test lights.
See what the new ECU does and check all connectors for good clean metal…
Again see if you can check all the plugs on the trany non should be loose and when pulled should be clean… a can of electrical spray would be good either DEOXIT or CRC’s or both
CRC is safe for all plastics
https://www.amazon.com/CRC-05103-Electronic-Cleaner-11/dp/B000BXOGNI
WD40 makes one too but usually not stocked at stores like Home Depot or Walmart
Scratch brush may be a good thin but usually a spray will work
https://www.amazon.com/Pixiss-Fiberglass-5-inches-Corrosion-Electrical/dp/B07M94Y12J/ref=sr_1_3?_encoding=UTF8&c=ts&dchild=1&keywords=Scratch+Brushes&qid=1623367394&s=industrial&sr=1-3&ts_id=1265107011
Don’t get the fiberglass refills as the brush lasts a long time… its bundled glass fibers and cleans metal surfaces very well if you can get the tip in… sprays above may be all you need.

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engine runs great problem remains transmission fault and you are correct 3rd and reverse is limp home and that it does i saw the problem comes up with many the static ecm olhms check is that a good indicator of its condition saw some numbers and pin values with that fellow on the east coast said something about a book of some kind just wondering what the series of events are leading to the failure mode thanks for you help on this

Check out ebook I have the mechanical version 4hp22 no electronics in trany…
http://www.jag-lovers.org/ebooks/view.php?Vbook=xj40&Vsection=8.3

also here is main index
http://www.jag-lovers.org/ebooks/bookindex.php?Vbook=xj40

a voltmeter will probably solve the problem something relatively minor… lets hope… good luck

there seems to be a lot of good info i will sort thru it with care thank you very much

good morning fault resolved by replacing the ecu with a reasonably priced used one from e bay thank you for your assistance on this while i have your ear i have had since i have owned this an issue with the boot locking system where if and my wife did lock it with ihe dash button the key fails to open the lock so it takes two people to open it maddening it is are there two solenoids in the boot latch mechanicals one for key and one for the dash asking for a friend thanks again

ECU great you got a spare… you could open the other intermittent one and most likely source of dodgy electronics would be the outside plug connector its solder connections to the PC board under magnification have probably developed hairline stress cracks… next candidate for intermittent behavior would be any lre power resistors and large 3 and 4 lead TO220 case semiconductors usually attached to heat sinks not sure if the ECU had those inside

As for boot lock dilemma my car has solenoid control but seems to be one solenoid… if the solenoid clicks its probably working… possibly you can latch trunk latch with boot open and see the solenoid in action?.. I did install a mechanical emergency pull ring for anyone stuck in trunk for latch release though nothing to do with you latch situation…

if solenoid is working and moving some lever in the boot next suspicion would be a broken internal part on latch… try some light lubricant inside the latch wont help broken parts but maybe something is sticking? …but is sounds like the latch mechanism works…never tried latching from dash then opening from trunk… yes that probably wont work …but key in door should open all the door locks and boot lock too… does it?

how much was you ECU?

ill give that a try thanks!

that was $37.04 right to my door !!

The better your magnifier the easier to spot hairline solder cracks makes the solder pad look like a volcanic island… Stereo Microscope would be superb… 37 dollars was a great price for and ECU… Super!

havent used one of those for a while now sounds like youve been there something you might like to do is take the component in question pot it in epoxy and carefully sand it examining as you go to visually confirm the failure mode of the component that method works well but go slowly and check often ill let you know what ive found here have fun and take care