99 S80 need to replace Crank Sensor
 

Hi,
I have a 99 s80 turbo that is occasionally hard starting and is coming up with crank sensor code. I am looking for any tips on replacing the sensor. It is a GM tranny and I am told that it is reachable from the engine compartment. Any help would be greatly appreciated.

GP

It is not that hard at all.
But another thing you might need to do is reroute the power wire from the fuse box to the starter. You will need to move it as far away from the cam and crank sensor wiring as you can.

When it is hard starting does the tach jump funny when cranking?

Thank you Tech,

I did replace the sensor and it did not help. Now that you mention it I have noticed the Tach jump around a little bit when I am cranking. By suggesting I move the power wire are you saying that the signal from the sensors is being interfered with by the magnetic field that forms around the power wire?

George

Yes that is exactly what I think it is. I have seen it many times.

Thank you for the information. I have checked out the wiring from the fuse box and I don't see any wires that are close to the Crank shaft sensor. Can you tell me a little more about the wire I am looking for?

Thanks

It is the BIG red power wire that goes from the fuse box to either the Alt or starter,

Thank you,

I will redirect the wiring as best I can. I will post the results.

I will wait to hear how you make out.

No luck with rerouting the power wire. It is still very hard starting, up to the point of almost killing the battery. I no longer have any error codes but still hard to start. Could it be the cam shaft sensor??? Any ideas?

Thanks,

Forgot to mention
 

I don't know why I didn't mention this but the problem has coincided with have my transmission rebuilt. It has been since that time that I have been having trouble. The transmission service guy said that he had trouble starting the car and it showed the crank sensor error code.
I also had trouble with the battery going dead really quickly. I took the battery to where I bought it (6 months ago) and they told me something was wrong with it and they gave me a new one. This of course, did nothing for the starting problem.
I didn't suspect the transmission work because the car cranks fine. I assumed anything with the transmission work would be a bad connection to the starter which would cause it not to crank.

any suggestions????

does it crank but not turn over? I'm having a similar issue...

Try running a ground wire from the engine to transmission to make sure they are grounded properly.

JVC,

The engine cranks (meaning turns over) but does not start. I had surgery last week and haven't had a chance to work on it for the last week. I plan on trying Tech's suggestion about running a ground wire between the engine and transmission. I was going to check for continuity between them before I run the wire to see if it shows any resistance.

George

Thanks Tech, I will try it as soon as I am able.

Sounds like a plan keep me posted.

Tech,

I tried the ground wire with no luck. I checked continuity before and after and it was a dead short between the engine, the transmission and the frame.
What did happen, was I took it out for a few errands and had the same trouble starting it that I have been having. On one of the times I tried to start it (it took a long time and I was regretting taking it out) it stopped cranking and I got a selonoid like clicking for a couple of seconds. It was like the battery had died but then it started cranking again without being sluggish. Finally it started and I got a message on the dash that I had never seen before. It said, "Immobilizer see manual". When I got home I connect a code reader and got the code P0335. The generic code definition is "Crank Position sensor A circuit malfunction". This was the code that the Transmission service guy says he got when he was clearing the transmission codes after he rebuilt the transmission. Because he had gotten the code I had replaced the sensor a few days later. That was about 2 weeks ago. This is the first time the code has reappeared.

Looking up the immobilizer message, it refers to the key transponder needing to be compatible with the code in the computer. I unfortunately only have one key at the moment. I have missplaced the second key so I can't try a different key. Will the starter crank but the computer not allow the ignition when it has key with a bad transponder??

Any suggestions??

I would not worry about the Key issue. I think it was just a fluke at the moment.

Here is the bad news though. I was saving this as a last resort. It also got conformation today at school. I will bet the tranny shop needs to remove the transmission again and clean the bell housing and motor good. Then put it back together and it should be fine.

There is a poor ground connection between the tranny and motor. The ground wire between the 2 should in reality fix it. But it will not always fix the issue.

I will also bet if the tranny shop calls the Dealer they will tell them the same thing.

Wow,

I would have preferred to have the dealer do it but they wanted 1500 dollars more to do it.

It should be real interesting trying to sell this to the transmission guy.

What do you think was the cause of the crank sensor code reappearing?

I will bet it came back due to the lack of grounding between the engine and tranny.
That would cause interference around the crank sensor throwing the code.

Well I thought I found the problem and was really excited but it turned out not to help.

I put the car on ramps and was really looking at everything I could to see if I could see anything out of place and or loose (I also have a front end clunking sound going on since the trany was rebuilt). Low and behold I found a ground wire buried behind some other things that was not connected. The cable starts from the fender area and looks like it should connect to the engine or transmission. Based on the size of the lug I chose to connect it to the transmission. I really expected this to solve the problem but no such luck.

One unusual thing that I did notice was that with the car not running I have a dead short between the cable where it connects to the fender and both the engine and the transmission but when I check for continuity when the engine is running I get reading on the ohm meter of about 20. Even more interesting is when I reverse the leads I get a negative reading which should not happen when checking resistance. I am wondering if I am getting a voltage leak to ground.

I will confess to becoming a little annoyed. I am going to the tranny guy tomorrow and get it up on the lift.