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I've had my share of water leaks in my S-Type (in trunk, in spark plug wells) but this tops them all. Car died at a busy intersection about 4 blocks from my house on a rainy day. Crank no start. Pretty dangerous situation, I was barely able to push the car out of the way. A few hours later I towed the car back home with my wife's trusty 1.8L Toyota 6 speed. Same year, similar mileage but 10x fewer problems.
Scotty Kilmer wasn't kidding.
When the rain finally stopped next morning I looked under the hood and found everything mostly dry. Checked spark plug wells, dry as a bone. OBD2 scanner showed fuel pressure at 54 PSI and RPM over 100 while cranking. Pulled a spark plug, found it flooded with gas. Started pulling fuses, found F19 (ignition coil plugs) blown in the engine bay. Replaced fuse, car started right away but fuse blew again as I was pulling into garage. Following posts on this forum I started chasing a chaffed wire, found nothing. Decided to pull the cabin air filter housing to expose the harness going into the firewall and immediately saw the problem.. water entering through the cabin air hole and leaking into the PCM !!! The most important electronic module (PCM) is located right under the largest hole in the firewall where water can rush in.
Pulled the PCM connector, got water works. Pulled the PCM got a broken levee. Judging by the amount of oxidation of the aluminum case, water has been in there for a very long time.
PCM full of rainwater
Why on earth the engineers decided to place the PCM in the most vulnerable spot for water leaks right under the huge hole in the firewall is beyond me. I let everything dry in the hot Texas sun and replaced the rotted out seals around the basket and filter housing with new weather stripping. Fingers crossed the PCM isn't toast.
Seal gone on basket. Connector seal (rubber) still good.
I resealed the housing with some weather stripping I had but I have my doubts this will be enough to counter the horrendous design.
New weather stripping
And new seal here
The car starts and runs but I haven't had the chance (and *****) to take it out for a drive, yet.
Lessons learned:
If you are blowing fuses the problem may be a flooded PCM.
Park Jag inside whenever possible.
Avoid driving in the rain.
Never buy another Jaguar or Ford. Scotty Kilmer isn't kidding.
Great find! Hope your PCM survived. Fingers crossed.
As far as the logic of why the PCM was installed there: Does the cabin air flow through that cavity? Just wondering if the logic was to provide cooling air for the module. Maybe the logic was reasonable, but not the execution...
Did you have any other symptoms recently? Or just the blown fuse and engine shutdown? Just wondering for future reference, to have the next guy get out his divining rods if his car experiences certain symptoms.
As far as the logic of why the PCM was installed there: Does the cabin air flow through that cavity? Just wondering if the logic was to provide cooling air for the module.
Yes cabin air flows through the cavity but unfortunately so can water when the seals crumble due to age, turning the PCM into a rainwater catch can. If they just moved the PCM a few inches toward the center of the car it would be a non-issue, the water would just drip on the carpet in the passenger footwell, no big deal. At least the IC board inside the metal PCM box is mounted upside down so it wasn't completely submerged. The fuse blew on hard acceleration as water splashed on the lower pins, 2 of which lead to the ignition coils.
Originally Posted by kr98664
Did you have any other symptoms recently? Or just the blown fuse and engine shutdown?
It has drains and the like to divert water. Something went wrong in this case. Texas heat?
How old is the car?
2003 S-Type 3.0 Sport 5-speed manual
Yes the car has drains but those get partially clogged with debris over time. Then depending on the angle of the driveway water can leak inside the cabin air filter opening during heavy rain. Gravity pulls it down onto and into the PCM due to it's poorly selected location. Of course I cleaned out all the debris and resealed the deteriorated seals as best I could but these nasty water leaks left a bitter taste. Not sure I can ever trust the car again to go on longer trips.
I moved to Texas 3 years ago from New York state. The car handles the Texas heat quite well, better than the NY cold. It just can't handle rain, never could. Years ago back in NY I had rainwater in spark plug wells: https://www.jaguarforums.com/forum/s...-wells-166914/ . Like everyone else I had water in the trunk many times.
PCM full of rainwater
