Interesting issue, easy fix

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Daughter in law called with her 2013 Hyundai Elantra making a strange buzzing noise. Opened the hood, started it up, and buzzing sound coming from the fuse panel. Opened it up and it was the coolant fan relay. Fan seemed to be turning, but relay was buzzing a lot.

Swapped relays with another position, but the coolant fan relay kept buzzing. Pulled the relay out, and the two coil pins on the relay socket (85 and 86) had 12v and approx 4volts on them. The approx 4 volts was fluctuating between 3-5v.

Grabbed my OBD scanner, and found 2 pending codes: P2101 throttle control motor circuit range and P0620 generator control circuit.

Seemed in my mind that all 3 of these issues (2 codes plus the relay issue) were tied back to the PCM.

Removed the connectors on the the PCM, and sure enough, found water inside one of the connectors. Used an air compressor to blow out any moisture from the connector and the PCM pin socket. Reconnected and all symptoms resolved.

I put some extra dielectric grease around the connector boot/seal to hopefully prevent any future issues.

Can anyone recommend anything I can spray on the connector pins to prevent or stop any corrosion? Should I try for a bit of dielectric grease right on the PCM pins?
 
One would think that connector would be environmentally sealed. Is it damaged somehow? Maybe missing the rubber/silicone gasket seal?
 
There is a product called DeoxIT that is made for this exact purpose, rejuvenates the electrical connectors.

Find out why the water got to the connector, then treat.
 
CRC makes several electronic component cleaners. You might want to check their site to find what product best suits your needs. Kinda strange that the PCM would be located in a place where water would easily get to it. I would also check to see if there is a TSB on this particular issue or maybe check some of the Hyundai forums to see if this is a known issue.
 
About a month ago my PCM (I looked it up) started making a high pitched whining noise.

Turned out I had a mosquito in my ear,
 
Originally Posted By: KGMtech
There is a product called DeoxIT that is made for this exact purpose, rejuvenates the electrical connectors.

Find out why the water got to the connector, then treat.


^^^ This.
 
Originally Posted By: KGMtech
There is a product called DeoxIT that is made for this exact purpose, rejuvenates the electrical connectors.

Find out why the water got to the connector, then treat.


+1

Root cause first, clean, then seal with a bit of dielectric as needed.
 
Caig DeOxit has a lineup of products.

The d5 spray is a cleaner, but there is a d100 liquid which has more cleaning power.

They have a gold product made for lightly oxidized contacts that use dissimilar metals

They have a shield product that does no cleaning, but it does protect and enhances contact conductivity.

I've had 3 cans of d5 spray. The first can left a reddish hue on Qtips and paper towels and seemed to clean much better than my last two cans that have no redish/pinkish hue.

I have had old crusty dielectric grease come ot of old connectors acting like someone stuffed scotch tape in the connector. I used crc QD cleaner to flush this old grease out and declared the connectr pristine, but then some DeOxit and some precision Qtips turned black as the contacts went from looking like 320 grit sandpaper to oiled chrome.

goto your pharmacy in teh dental care section. They have these micro bottle brushes for getting between teeth.

den tek bottle brushes

Also get some of these:
tamiya+precision+swabs

The amount of oxidtion I removed from all my sensor and computer connection contacts with these tools and Deoxit d5 and d100 was astounding.

After they are cleaned, I spray them with the Deoxit Shield S5 spray, then reseat them, then use Dielectric grease and try and force it into the closed connection to seal it from moisture. I will not fill connections with dielectric grease and force them together anymore. not after seeing it fall out of an older connection like Scotch tape layers.
 
I've got a can of the DeOxit D5 stuff on the way. Should be enough, doesn't look like the moisture had been there long, so not bad corrosion. I'm going to examine the rubber connector boot/seal to see if there are any rips/tears.
 
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