X59 connector condition: green with corrosion

[mklein9]

My 2002 996's X59 connectors have been problems in the past and may be acting up again.  Back in 2014 I got the car with newly repaired engine due to IMS bearing damage from Flat 6 Innovations and the instant it came off the truck it had severe running problems which, after much effort and expense, were tracked down to bad X59 connections.  For some reason it didn't show any issues at Flat 6.  Last week a new CEL showed up with a P0342 code -- bank 1 camshaft hall sensor/sender with implausible or low signal. After the experience in 2014 I didn't think the sensor was faulty, but more likely some connection along the line.  Below are photos of both halves of the two X59 connectors. The upper one, X59/1, looks clean. The lower one, X59/2, and which carries the crankshaft position sensor (2014's problem) and camshaft hall sensor (the current issue), is a different story.

 

I sprayed Deoxit DN5 liberally into both halves of both connectors, used the locking ring to slide the halves together and apart and together again at least 5 times, and hope for the best.  The CEL is gone, but I wonder what's next.

 

Any advice for how to do a more thorough cleanup of these connectors? In the photos, the first two are the X59/1 connector and the last two are X59/1 which looks much worse; I've marked pin 14 which is the Hall Sensor pin.

[dporto]

First, clean all the oxidation really well until all the green (copper oxide?) is gone. Try not to use any/much abrasive as it will just remove more plating (which was probably already done at some point hence the oxidation on the copper). Once you get it clean, use plenty of dielectric grease when you put the connection back together (it looks like this was done to the other connector). The dielectric grease will repel moisture and reduce or hopefully eliminate the oxidation you've been experiencing. Good Luck

[Ahsai]

I remember your case. it was a long winding tough one to crack.

 

It's hard to see corrosion on your photos. Could the green gooey stuff the Deoxit discoloring over time? The gooey stuff also looks like silicon grease?

 

BTW, why it can't be a simple sensor failure? Just curious...

Edited October 15, 2018 by Ahsai

[dporto]

^^ I think (or should say assume) the clean/non-greening connector is the good one (no faults). It certainly could be a failed sensor, but got the feeling the OP had already determined that the sensor was/is ok and had tracked down the fault to the connector itself. It looks to me like the green is indeed oxidation, but obviously no way to tell from just a photo...

Edited October 16, 2018 by dporto

[mklein9]

On 10/15/2018 at 8:26 AM, Ahsai said:

I remember your case. it was a long winding tough one to crack.

 

It's hard to see corrosion on your photos. Could the green gooey stuff the Deoxit discoloring over time? The gooey stuff also looks like silicon grease?

 

BTW, why it can't be a simple sensor failure? Just curious...

I am not really sure what the green stuff is. The consistency does seem like it is greasy, but hard to tell.  So it could be old dielectric grease, maybe reacting with Deoxit DN5.

 

I doubt it's a sensor failure because the symptoms were gradual and intermittent. I had noticed a few momentary power losses over the last month or two that preceded the CEL, which would be likely results of intermittent bad hall sensor signal.  The CEL went away by itself too.  Since I've taken the X59 apart, sprayed more Deoxit DN5 in them, and inserted/removed them numerous times this weekend, the engine has been flawless again.  Only 2 days so far.

[mklein9]

Was running great for 2 weeks and the same issue came back, even more frequently.  Usually P0342 and sometimes P0344, with CEL.  I cleaned the X59/2 connector with Q-Tips and the green stuff is gone. Seems unlikely to be dielectric grease since dielectric grease should be very stable over time.

 

I've tried measuring resistances and voltage but I must have gotten something wrong because they didn't make sense. With hall sensor connected, measuring at the DME connector (unplugged from the DME) from hall sensor signal to ground was an open circuit. With hall sensor disconnected, DME plugged in and ignition on (but engine not running), the hall sensor connector pins measured 11.7V at the + terminal and 11.2V at the signal.  OK but from the wiring diagram the voltage to the Hall sensor should be 5V. It's a bit of effort to get all the right conditions to measure each part of the circuit so I'm just going to order a new camshaft position sensor ($100 for the Bosch version vs. $250 for the Porsche version), install it, and see if that fixes it.

[Ahsai]

I agree the voltage reading is strange like you explained. I wonder if one of the 2 wires (+5v power and signal) is shorted to +12v somewhere.

 

If you can measure the DME C7 pin (red/violet wire), that would be good. It should be +5v feeding the two cam sensors.

[mklein9]

I measured and looked today and found:

1. Continuity from DME to sensor connector was fine on ground and signal (0.1 ohms), but +5V supply was open (DME pin C7, X59/2 pin 22, sensor connector pin A3)
2. Also checked continuity from X59/2 connector both ways (to DME and to sensor connector), which had the same results as #1
3. Checked resistance between sensor ground and sensor signal which was open, so given that fault code P0342 appears together with factory code 112 ("below limit" i.e. short to ground) it must be something other than wiring introducing a short or other type of no signal
4. Reconnected battery and DME connectors, turned on ignition, measured voltage at sensor connector supply pin (A3) and no question, it is a solid 11.6 V, equal to battery voltage

The only conclusion I can come to is that even though wire colors for sensor supply wire (RD/VT) match the wiring diagrams for my model and year, the diagrams are wrong. The connection to the sensor must be +12V, not +5V.

 

So I went ahead and replaced the sensor, cleared faults, and drove it around the block and it seems fine for the moment.

 

To the original topic: I also cleaned out more "green stuff" from the X59/2 connector that I thought was corrosion, and it's definitely a grease material as it comes off easily, leaving surfaces that look just fine. Probably overly aggressive use of dielectric grease in the past? This connector was heavily worked on 4 years ago while diagnosing and fixing what did appear to be a wiring problem with the crankshaft speed sensor.

Edited November 18, 2018 by mklein9
Corrected pin number