PontiacBonnevilleClub.com

My friend has a 1994 SSEi, excellent condition, super picky about his vehicles. He's the second owner (his sister bought it new) but has had it for many years now. I'm not sure of the current mileage though. In any event, he was driving the other day when it pretty much stalled out and died. The Service Engine Soon lamp illuminated, along with the TRAC Off. He's been able to start it since, but it's intermittent in whether it will fire up and run well or if it runs rough and stalls.

I scanned it today and he has a few codes...

Current:
P0342 Cam Sensor Circuit
0075 PCM Requested TCS to be Disabled

History:
P0341 Cam/Crank Error
P0342 Cam Sensor Circuit

I'm not at all familiar with this vintage of Bonneville so any helpful thoughts will be appreciated. When I searched the forum for these codes, it seems that any of the results I found described numerous, apparently unrelated DTC's and possible PCM faults. Since this is pretty specific, possibly a bad sensor?

The car was parked all winter but ran flawlessly when put away in the fall. He did an engine wash recently but had it out and driven at least half a dozen times before this hiccup.

And... I might as well throw in a pic just for the heck of it...

Since it outright died, I'd think the crank sensor died. A bad cam sensor or missing cam magnet will still allow it to run, but poorly. In theory, it should still run with a bad cam sensor. But, check the cam/crank sensor harnesses for bare wires, remove the cam sensor and turn the engine by hand, watching for a magnet about the size of a dime in the cam gear, or damage to the back of the cam sensor.

There are 2 ground buses--1 by each front door, wrapped in electrical tape, which wreak havoc when there's any corrosion on them.
Driver's side has been known to cause stalling issues but I wouldn't automatically rule out the passenger's side bus.
Details here:
viewtopic.php?f=19&t=30286


To check the cam sensor, see this thread: http://troubleshootmyvehicle.com/gm/3.8 ... m-sensor-1
This shows how to check the magnet
http://www.pontiacbonnevilleclub.com/fo ... ilit=P0341 Cam/Crank Error#p259729

This one is for the P0342 but you'll likely have it resolved with the 1st 2 posts' info
https://www.obd-codes.com/p0342

Note that poor grounds to the battery and/or starter are among the list of possibilities.

Thanks gents! I'll dig into this and see what I come up with.

I did look over the website regarding testing the cam position sensor. I must say that I'm not crazy about some of the advice they offer. Piercing insulation is, generally speaking, a very bad idea. This leads to corrosion of the wiring down the road and nothing but more grief. Now, it's not always terrible. I've done quite well on occasion troubleshooting and repairing or manufacturing new wiring harnesses because others have used this method on friends vehicles

That aside, all the info you guys have offered up is very much appreciated!

ddalder wrote:I did look over the website regarding testing the cam position sensor. I must say that I'm not crazy about some of the advice they offer. Piercing insulation is, generally speaking, a very bad idea. This leads to corrosion of the wiring down the road and nothing but more grief.

I agree with you on the wire piercing but still appreciate the step by steps on that site.
You can either back probe using t pins or actual probes or just apply a dab of high temp rtv , if electing to pierce the insulation.

My bet is that if I use my meter on mV, or an oscilloscope, I can pass a magnet by the sensor and see some deflection. I've done this with wheel speed sensors and spinning the hub assembly. The site does offer good information as you say.

So is this bad?????





I finally had some time today and went to my friend's place to dig into the Bonneville. Over the past while, he's tried a few things to try and resolve it including replacing both the cam and crank sensors. Neither of these had any positive effect.

So... I dug into the wiring harness and just beyond where it branches off to the cam position sensor, I found the three wires inside the split look bare of insulation and shorted together. It seems that the split loom was virtually destroyed and fell apart anywhere oil and/or grease had seeped onto it. There were other places that were similar but at least the wiring remained intact.

After repairing the harness, everything is working flawlessly. We harvested some wire from a vehicle at the wrecker, along with some replacement split loom. I didn't want to use regular wire because engine compartment wire insulation (and split loom) is rated for much higher temperatures than wire used inside vehicles. I also wanted to maintain the wire identification (colour and stripe) for consistency and troubleshooting later, if necessary.

Anyway, thanks guys for the tips!

did the balancer rub on the wires at all? That is fairly uncommon among the 3800's unless that wire/wires pop out of the holder.. But with the wire loom being destroyed the wire rub would be possible.

The affected area was definitely away from any moving parts. It was fairly close to the valve cover that had been leaking a little over time. The split loom seemed to be just mush that disintegrated when touched. The only area that was affected though was saturated with oil and grease. The remaining split loom was well intact and dry over the entire length of that harness. The insulation on the wires appeared to have melted into the strands of wire. What wasn't there just melted off.

I'm just glad you found that Darcy... Good to see another classic still running the road

Thanks. It's a beautiful car. I'd purchase it for my small collection if I had the room to store it properly and time to care for it. I was so glad to be able to help them out, which of course is a direct result from the help and insight I received here. This vintage of Bonneville is definitely new territory for me. It saved a lot of time when I was able to focus on some known problems areas.