NJJOE4X4

I have been looking for what is wrong and I can`t figure out what is the problem. It is getting fuel "60psi" fuel pump working. When I put the key in the ignition, nothing out of the ordinary happens to the dash light ,No security light staying on.

The one current code
28 TCS Traction Control System
U1016 H C " Loss of Communication with PCM "

after battery died trying to figure out what was going on, I charged the battery, reconnected it back up code was not there. I checked all grounds all fuses and still no luck when cranking the Vett.I did get access to the PCM behind the passenger`s side wheel, I disconnected the long connectors and they looked clean inside so I reconnected and tried to start the Vett again. "No Luck"

I`m trying to figure out my next step, If it is the Crankshaft Position Sensor,..if it is that would I not get a code?

I did hook my scan gauge tool and I got no codes. Dic has no codes at the moment has history codes but no current.

I tried switching relays "No Luck". I know there is a thread about ignition lock. before I take the dash apart. if there is some way of testing the PCM.

NJJOE4x4

Bill Curlee

Hmmmm,, Have you checked ALL the PCM fuses for proper voltage measured at the test slots on top of the fuses to chassis ground??

Measuer each slot on the fuse to ground.

Some of the fuses are powered when the ignition is ON. All the fuses should read FULL battery voltage

That would be the first place to start.

Bill

NJJOE4X4

Bill
If it was a cam/crank sensor I would get a code right? I`m trying to get that out of the way as not a cause. I`ll check the voltage on the fuses tomorrow. I was using just a test light (light was good not weak) but I`ll check the voltage thou. The one ground I could not see or feel was G107 behind drivers side head back. That is a ground for the coils
tight spot .Do you have a pic or tell me where it is.

I remember reading a post where the drivers seat control was the problem .I`m going to check that tomorrow also.

martysauto

Does your tach read rpm's while cranking? Does your scanner read rpm's while cranking? Did you check to see if you have battery voltage to the ignition coils?

3boystoys

All the GM's I've had over the years didn't show the crank sensor code till they actually failed completely. When they first started to get ill they wouldn't throw a code. You need a scanner that shows the crank sensor pulses, the DIC is not enough to shoot this.

Bill Curlee

IF,,,, you had or have an old Points Dwell Meter (See, I knew that that old crap would come in handy some day) you can probe the coil connector PIN "C" and read the pulse on the trigger pin:

Pin C = Ignition Coil Signal from the PCM:










While you are there you can read Ground and coil power (ignition switch ON for the voltage measurements).

Dont forget fuses 16, 18 & 22 as they supply power to the coild and injectors.

NJJOE4X4

I checked the fuses 16,18,22 before I turned the ignition on and there was not current going to them, after the the ignition was ON the fuses 16,18,22 all read the same voltage 11.98 (battery was at 12.03).

I did check the coils and the same thing ignition off no current to the coils (to be expected),when I turned the ignition ON the coils where getting current to them. the same for the injectors. the current came on after turning the ignition key to the run position.

When cranking the I did not see the rpm`s moving. I`m starting to think it might be the crank sensor. testing crank senor without taking it out, what tool would I need ?

Should I just drop the exhaust and take the out the starter and just replace the crank sensor?

~Josh

If it were me I'd replace the crank sensor.

Bill Curlee

Heres the crank and cam sensor schematic:

3boystoys

If it was really a DEAD crank sensor, you would have a code for sure. I wouldn't swap anything till I checked again for codes and/or get a better scanner on it so you can actually see the crank pulses. I'm guessing you didn't check fuel pressure or spark? If your scanner is basic it may not show you much.

NJJOE4X4

Ok what scanner can I get to read the rpm`s and also to read the crank pulses? I was going to just replace the crank position sensor but if that is not the problem i would just be wasting time and $ so I would rather spend it on a new tool (scanner). Is there a good scanner that's not too expensive , I have a feeling that a good scanner is gonna be pricey.

Joe

3boystoys

Last actron I bought was $200 on sale at Autozone I think.

http://www.actron.com/product_detail.php?pid=16366 I also have a more expensive laptop scanner but I think the Actron is what you need. You can capture runs and replay and graph many sensors. Pretty nice for $200.

Are you still getting this?
U1016 H C " Loss of Communication with PCM "

That would be a big problem.

Bill Curlee

Unless you get a really expensive scanner like a Snap on or Matco tools scanner or the GM Tech 2, I dont think its going to show the crank pulses.

You can read Ignition Advance angle on my actron CP 9180 but no Crank Sensor data.

Bill

3boystoys

My Autoenginuity does for sure, i'll have to check my actron tonight.

NJJOE4X4

No current codes just history codes.
I do have actron cp9125 obd II pocketscan but it does not show any codes. I`m getting fuel its reading close to 60psi at the fuel rail.

Pulled plug wire both sides test with plug to engine block and no spark on both sides.

Joe

martysauto

If you have no rpm's while cranking, check for battery voltage at terminal c at the crank sensor. If you have it disconnect the battery and unplug the PCM connectors and check continuity. Also check for shorts to ground. If it's all good, replace the crank sensor. It all starts there.

NJJOE4X4

I guess that there should be NO continuity between A to B, and also
B to C on the Crank sensor right? I`ll see if I can get to it .
Hey martysauto do you have a shop in Cinnaminson ?, I lived in Pennsaunken growing up.

3boystoys

If it's a failed crank sensor, you will get a code for sure, the U1016 loss of communication to the PCM seems to be the issue you need to sort out. I "assume" you checked all your fuses??

NJJOE4X4

Ok I ordered a crank position sensor from the dealership, it will be in tomorrow. I was gonna get one from the auto parts store but I heard of people having problems with them so I figure just to play it safe get the oem from the dealership.

martysauto

You want to check continuity in the harness, from the sensor to the PCM.
You can PM me with your cell number and I'll call you and give you more info.

My shop is in Delran, I live in Cinnaminson