2003 S60 Starts then dies immediately(Clean PEM 8634953) Topic is solved

Post by **RickHaleParker** » 27 Feb 2018, 09:13

If you going to leave it mounted on the tank, spray the PC board with Conformal coating. Conformal coating will protect the electronics from contaminants. Make sure you mask off the edge connector before you spray.

A Conformal coating is a protective chemical coating or polymer film 25-75µm thick (50µm typical) that 'conforms' to the circuit board topology. Its purpose is to protect electronic circuits from harsh environments that may contain moisture and or chemical contaminants.

Post by **abscate** » 27 Feb 2018, 10:50

The Volvo TSB says the relocation harness does not apply to the steel tank car applications. I didn't move mine as I didn't have the harness. Im beyond the 10 years for the recall Im guessing, anyway. Given my first one lasted 13 years, I doubt I will need another. I don't see why you couldn't use the harness to move it, but I have no more info on that.

By the way, the corrosion is from the inside of the heat sink on the PEM,not intrusion from the outside. It is really well sealed up.

Brain flash - I wonder if the mounting of the PEM in the trunk solves the problem by letting Al oxides fall to the bottom (SIDE) of the case rather than landing on the circuit board.

Hmmmm

Delirious · Post by **Delirious** » 27 Feb 2018, 12:23

abscate wrote: 27 Feb 2018, 08:05 You can back rinse that circuit board with Contact cleaner and see if you move the Al crud off it enough for it to work again

Mine has run a couple 1000 miles after doing that.

The car purrs like a kitten again! Huge thank you!

Post by **abscate** » 27 Feb 2018, 13:11

NICE!!!!

Post by **oragex** » 27 Feb 2018, 15:57

I checked today at the scrap yard, there were many models with the steel tank (judging by the rust on them) but most had the external fuel filter and couldn't see the PEM on top of the tank. My 2003 has steel tank but internal (at the pump) non serviceable filter and the PEM sits gently as in the picture above in the topic. Correct me, but only cars with steel tank and in-tank fuel filter had the PEM 'outdoors' sitting on the tank.

Anyhow, time to remove mine and give it a good cleaning. It has already been replaced but nothing like preventative maintenance: I'm going to put a smear of silicon all around the seal, then put the cover back on. I use the higher quality 'outdoors' silicone from the hardware store, worked fine on a few other modules on the car.

Worth noticing, several modules had issues with water ingress/corrosion, the most infamous and expensive being the DEM of the AWD Haldex, a mere $2000 or so for the tiny module in parts only and hardly compatible with other used units: really worth removing and getting a nice clean up and resealing on the AWD cars, may save some coins.

don_moore_1904 · Post by **don_moore_1904** » 03 Nov 2018, 22:18

Personally, I would advise not attempting to clean but buying a used PEM from a scrapper, because there were many more PEM modules installed inside than outside, and these models are being scrapped at increasing rates. I got one for $40, and it looks virtually brand new. Taking them apart is problematic, since the plastic has aged and the locking tabs crack easily. I would also highly recommend relocating the PEM inside the car to avoid future issues.

Post by **cn90** » 14 Nov 2023, 21:17

Question for the PEM gurus...

- I understand very often we hear PEM mounted under the car (such as above fuel tank or in front of RR wheel area
in the XC90) has problem, presumably due to salt etc.

- For PEMs mounted inside: has anyone here seen failure of the PEM that is mounted in the rear seat or trunk area?