Help! Help on using TECH II to test shocks/actuators on 97

[C4TOMCAT]

[h=2]I have a Tech 2 and have gone thru the programs and screens and done the basic tests. I am trying to use it (suppose to be able to access/test shocks/actuators) to find out why my shocks are inoperative. Can anyone provide me instructions or a link on where this test is performed in the tech unit. my card is good up to 2013, have scrolled all screen areas but cannot see where/how to test shocks.[/h]

I have seen some youtube videos on the tech but nothing in the area I need assistance on. I have NO DTC's set but IP message of shocks inoperative, max speed 80 mph.

thanks in advance I also posted in the general section​

 

[Hib Halverson]

Forget the T2.

The C5 has on-board diagnostics which will display any fault codes set in any of the car's controllers which store codes.

The instructions on how to "pull" codes from C5s are listed in a variety of places on the Internet, including this site.

Search for the instructions, read codes for RTD and post them, here. Once you post the codes, i can tell you what's wrong with the shocks.

 

[gmjunkie]

To pull codes on C5
Turn the key to the ON position, but don't start the engine. Clear any present messages by pressing the RESET button. Hold the OPTIONS button down, and press the FUEL button 4 times. This will get you into the CODES section of the DIC. The computer will automatically display all the codes your car has created. It will cycle through each code every 3 seconds. Any code that ends in H is a history code (something that has occured in the past) but is fine now. Once the computer has finished going through all of it's codes, press RESET to enter Manual Configuration mode. It should start with a module and show "NO CODES" or "# CODES".

 

[C4TOMCAT]

Shocks inoperative

Thanks for the reply's and the pulling of code information but already understood that process.

I have pulled the codes on the IP and there are NONE. But the message for the shocks and reduced power shows up. The FSM talks about some soft codes that the way I interpret it are intermittent quick faults and if that is setting the message but not storing a code I have no way to trouble shoot with a starting point. So I obtained a TECH 2 and have paged thru it, saw some info in the different screens but cannot find where to test for the shocks like I have done with other sections...ie a/c, doors etc.

So, not being a trained tech on the use of the tool I am wanting to see if there is any link or info on specific problem solving using the tech 2. obviously in the hands of the trained tech it is a valuable tool....now that I have one I would like to at least become proficient in its use on my 94 & 97 vehicles. I will start today putting on stands and checking all the underneath connections.

any help/guidance/direction or links is appreciated.

tom

 

[C4TOMCAT]

Shocks inoperative

ok, car up on stands but decided to give the Tech 2 another try, no communication with 97.

went to the 94 and connected the Tech 2 and had communication and access to screens.

SO, anyone give me directions as to why/how to determine the NO Comm issue. I did not find a fuse for Comm Link. Where should I start.

Where to start....I will finish checking out all the connections this morning and then look at the FSM wiring for any communication link info.

Any shortcuts to resolving this issue or directions is appreciated.

tom

 

[C4TOMCAT]

Shocks inoperative

Anyone help on trouble shooting the DLC since I do not communicate with my 97 vet....94 vet does so I know its not the Tech 2.
Pin 2, Pins 4 & 5, and pin 16 I understand are the main ones.....what values or readings should show up on probing them and what to use....ohm meter or voltmeter ???.

also, is there a way to verify the dlc wires are solid to the (pcm or bcm )device its getting its info from.

thanks still working the connections under the car.

OK, NO power to pin 16 on DLC....cannot find any fuse listing for it but its suppose to be 12 volt hot all the time.


can anyone point me to its source. thanks tom

 

[C4TOMCAT]

Shocks inoperative

oK, now have power to the DLC, tech 2 powers up but when I try to get communication it fails, tells me to check connection (on/off)

how to check the bus or what to do next to overcome the communication problem with the Tech 2


out of effort for today. any suggestions for tomorrow would be appreciated. spent most of the afternoon tracing out the power to the DLC and now that its there another issue....communication.


later tom

 

[Hib Halverson]

If the C5's on-board diagnostic function displays no codes but the "service ride control" light is on and the max speed 80-mph message is on the IP display and you have a DLC connection problem with a Tech 2, my advice is to take the car to a GM Dealer or an independant shop with experience servicing Corvette electronics.

If you still want to do the DIY thing, then you're going to need to "backtrack" in the diagnostic process and approach the car with the assumption that the Class 2 communcations network on the car is not working. You need to repair that, first, then move on to diagnosing the ride control system issues.

The place to start is FSM Vol 3 page 6-419.

 

[C4TOMCAT]

Shocks inoperative

If the C5's on-board diagnostic function displays no codes but the "service ride control" light is on and the max speed 80-mph message is on the IP display and you have a DLC connection problem with a Tech 2, my advice is to take the car to a GM Dealer or an independent shop with experience servicing Corvette electronics.

If you still want to do the DIY thing, then you're going to need to "backtrack" in the diagnostic process and approach the car with the assumption that the Class 2 communications network on the car is not working. You need to repair that, first, then move on to diagnosing the ride control system issues.

The place to start is FSM Vol 3 page 6-419.

Hib, thanks for the reply, I have power now to the DLC BUT still get the no communication message, I have to finish checking the connections under the car tomorrow and put it back on the ground. is there a way to view the PIN 2 output/voltage or whatever it puts out with a volt meter to see if anything is available at the pin. I know the Tech 2 works on my 94, I verified that so now that the power is available to the DLC my next step would be to see what pin 2 is doing, if anything. if nothing is available at pin 2 then I would need to trace that line back to the PCM or BCM and verify the line is good. I have not checked out that part and won't until the weekend but need to put it into shape again to drive as other than the 80 mph limitation and shock error it ran fine. if you have any info on where I could tap in a probe to pin 2 and tap it at the appropriate pin on the pcm or bcm it would help in either seeing if the communication functions or if I ohm out the pin 2 to ???? pin on the computer.

enough for tonight, I'm sore and tired. Thanks tom

 

[Hib Halverson]

As I said before, if you have no scan test data coming over the Class 2, you need to stop working on the shock problem and begin working on the lack of scan test data. The diagnostic info for that problem starts in Vol 3 of the 1997 Service Manual on pg. 6-419.

Once you solve the no Class 2 data problem, then you go back and get codes from the chassis controller, diagnose RTD and repair as necessary.

Good luck!

 

[C4TOMCAT]

shocks / no communication

first thanks to all for the reply's. Being a Senior Citizen requires me to get all the assistance I can from this GREAT forum and its MEMBERS.
2nd I slept on it and this morning went out and just did a step by step walk thru the tech 2. IT WAS WORKING CORRECTLY ALL THE TIME, I JUST JUMPED THE GUN and went directly to CHASSIS directly and that is the only time I do not have communication.
I was able to run all the diagnostics this morning..lights, windows, horn, traction control,etc UNTIL I went to the chassis mode.
I thought all along since comments were made that chassis was where my info on the shocks would be I assumed ??? wrong by going there directly.
So, it appears the issue is with access to the chassis module. I will now have to ask for assistance on determining the loss of CHASSIS access, any wire schematic info (I have the FSM, just would like any page direction or specific tests/tracings/short cuts others have found useful), where the chassis module is located and method to trace problem. Still not finished with checking under car but will by noon, need it on the ground and available.

later tom

 

[dadaroo]

Had not seen your post here also. I'll just provide a summary of what I said on the other forum just a minute ago for others to see.

I think the ESC module is not powered, not grounded, serial bus wire issue, or bad ESC for No Comm to show up. That would prevent codes from being thrown but not prevent the message and speed limit.

If the RPO had been removed correctly then the message and speed limit would not show up.


Mr. Sam

 

[C4TOMCAT]

info update

ok, i pulled the ESC module from the LR TRUNK panel, all pins loo good.
Pulled the RTD relay out of the fuse panel by battery and ohm checked it at 86.6 ohms, contacts NO were NO. I may try to figure a way to recheck the contacts in the panel this weekend to see if they close. by the ohms of the coil I suspect they will. I did find the circuit listing for the serial bus dark/blue wire and inspected for any issue and found none.

any way of verifying or identifying the info on the label, price, superseding data, updated or replacement items etc.
I only ask in case I need to change it but not there yet. wonder if the one in the 94, if same ????, would work as a test but sure do not want to damage th 97 system or the 94s esc since that car currently has no issues..I will pull it tomorrow maybe and compare....unless someone on the forum can confirm its good to swap with not damage potential.

enough for now....need to step back now and see if anyone has a solution to the Tech 2 having a momentary flash of the CVRTD screen data prior to the comm message. thanks all....although in a way this is fun, but only if you are reading this as a viewer, not the doer.

 

[C4TOMCAT]

tech 2 issue recap

Fresh morning, so just want to recap where I am with this challange.
1 I get the message "shocks inoperative, max speed 80 mph"

2 went thru the DIC IP and checked codes....none found!

3 hooked up recently obtained TECH 2 to identify issues and checked car for DTC's..none also found. In the chassis section I get no DTC's listed and do not get the no comm when accessing F0 for the DTC's

4 I could access all TECH 2 areas ok until I got to the CHASSIS CVRTD screen saying "establishing communication" at which time I get a micro second blip of screen data then the TECH 2 shows "no communication" (key ON/OFF)

5 took the TECH 2 to my 94 coupe and verified that the instrument could read all areas and screens thereby pointing me to the 97 and the chassis section to troubleshoot.

6 today will look at ground connections...especially those two closest to the ESC moudle in the rear LH Trunk area.(I have in the past gone thru all the grounds per forum member B. Curlee's findings and posts.) May be time to revisit them after 14 yrs.

7 ESC module removed and connections verifies as nice and clean, no loose wires or pins.

8 pulled the RTD relay in the fuse box, engine compartment, ohmed the relay @ 86.6 ohms and verified contact N.O. were N.O. (will attempt today to hook up volt meter to the RTD relay when accessing with the Tech 2 to see if the relay is actually functioning under loaded conditions. (not sure WHEN or HOW this relay becomes energized or under what conditions...maybe during selector switch activation, load changes in travel ??) ANYONE have insight on this.(more FSM reading to do this weekend)

9 QUESTION unclear to me how or what I mean here but wonder how the serial bus data line, RTD relay, and Tech 2 interrogation sequence correlate with this problem. need to understand the schematic control sequence of signal travel. since modules talk to each other on the same bus...could another one be interfering...I BELIEVE BECAUSE I SEE THE MICRO SECOND FLASH OF THE CHASSIS DATA SCREEN BEFORE IT GOES TO NO COMM that the SERIAL BUS COMMUNICATION line is good.....then what is disrupting that com link. (not much sleep last night with all this swirling in my head)

ok, guess thats about it as a summary...today put it up on blocks, check grounds, check if ESC in 94 is same as ESC in 97 for comparison, figure a way to see RTD become energized with volt meter when using Tech 2..if applicable.

 

[C4TOMCAT]

tech 2 issue recap

ok, went out this a.m., jacked car, re-installed ESC, hooked up volt meter to RTD Relay, Hooked up Tech 2, VIOLA....I do not know why but it is talking and communicating when before it did not. Is it the ESC, Could the Volt meter connection have affected the way the relay pulled in...?? will retry again with all disconnected in awhile. I still have to check out the grounds, have not done anything other than jacking, hooking relay, using tech 2 as eariler
once grounds are checked then the road test as long as it still continues to communicate. Wonder if leaving the ESC disconnected all night (too tired last night) has anything to do with today's success.

here are the pics.

 

[C4TOMCAT]

more pics of working chassis section

 

[C4TOMCAT]

update

happy it is working, unhappy no definitive solution was identified as of this point. no difference when I removed the volt meter....still communicating ok

working on the grounds just to be sure, looking at possible wire issue in ESC connection both in the trunk and at the underneath connector of trunk.

Cannot imagine the $$$$ if at a dealership for the time I have spent. I am around 40-50 total time spent over the past 3 weeks working this challenge.

break time, be back later with any findings

 

[dadaroo]

You never actually tested the relay to see if the contacts closed and provided continuity, Looks like you were trying to measure voltage drop across the contacts of the relay. By doing this you actually may have created a voltage path around the contacts adequate enough to power the ESC.

That is why in doing diagnostics you look for power and ground at the component first and then work backwards, not the other way around.


Mr. Sam

 

[C4TOMCAT]

Relay

You never actually tested the relay to see if the contacts closed and provided continuity, Looks like you were trying to measure voltage drop across the contacts of the relay. By doing this you actually may have created a voltage path around the contacts adequate enough to power the ESC.

That is why in doing diagnostics you look for power and ground at the component first and then work backwards, not the other way around.


Mr. Sam

The meter is measuring the coil and it did change voltage state. But you are correct it may have altered the circuit just enough....That's why others looking at a challenge is just good business.

I will go out and do the contacts today.

Question.....with the meter off and if it was an alternate path...now that the meter is not in the path....access is still available....which would lead me to believe the contacts are closing. still unclear as to what the initial issue for no comm would have been unless it was the ESC. I did not see a RTD relay part number but did find a relay for the fuel listed at a local parts house.

ok, the contacts are working, voltage drop with relay N.O., coil activated and voltage = zero. screen access ok with just the tech 2 connected and able to run diagnostics.

Question.....wonder if the movement of the fuse box pulling and replacing the relay is the fix, the grounds did not get done until after it was able to read the chassis....just more things to ponder.

again, thanks for sticking with me...still foggy so have not road tested.

 

[dadaroo]

Never mind my comment since you were measuring across the coil. That's not really where you should be looking for diagnostics.