Yes checking for communication and also checking if you can look at some live data as in the screenshots below !!

 

Thank you so much, Rob!

At least I'll have a starting point, I'll get to a Tech 2 Monday morning if possible. Once we see what we see I'll try and update my situation!

Ron

 

Well, hooked up my Tech 2 that I bought in 2017 this morning. I had only powered it up via its 9 v battery before placing into my tool cabinet for future use. Plugging it into the car's OBD 2 port, it wouldn't power up. Checked it on two other vehicles as well, still not powering up. Checked the power and ground pins in the cable, both OK. Just my dumb luck, didn't think it necessary to check by connecting to car upon purchase, just assumed if it powered via 9 v battery all would be good. Poor assumption . . .
I'll be out searching for another source of OBD testing. Would either/or O'Reilly or Autozone possibly work?? Thanks guys, still thinking I must need a remote receiver . . . . where is the darned thing located on a2004 convertible, mine's not as shown in the 2004 service manual nor in other spaces I've seen mentioned. Sheesh!!

 

A 9v battery is not used in the Tech 2…check fuse 7 in the IP fusebox…that powers pin 16 of the DLC which will power the Tech 2 and which is “hot at all times” !!…you don’t have the cigarette lighter adapter ??

 

When you said you’re Tech 2 isn’t working I thought maybe this is tied into your problem…pin 5 on the DLC (below pic) is a ground and I think the Tech 2 uses it for it’s ground also to work…pin 5 is grounded at G104 which is located just forward of your battery on the right hands frame rail…the ground for your RCDLR (RFA) also uses this ground so maybe your RCDLR just has a ground issue…before these 2 grounds go to G104 they go to a splice pack (SP208) which is somewhere on the right side of the IP…if fuse 7 is good and you have power at pin 16 at the DLC connect your multimeter between pin 16 and pin 5 and see if the multimeter reads system voltage…this is just a SWAG !!…the only thing is you should see a “No Comm” with the RFA !!

 

My Tech 2 is supposed to be powered by the auto's OBD port when connected to the auto, through pins 16 and 4 if I'm reading correctly. It does not power up on the Corvette nor any other car when it is plugged in, which according to the manual it is supposed to do. It doesn't have the cigarette OBD lighter power, uses a 9 volt battery internally when disconnected from the car. The 9 volt power is not for diagnosis, only for viewing saved data after diagnosis, printing results, etc. I checked the OBD cable's pins for continuity, all is well there. I think I have an OBD problem . . . . .

 

If it doesn’t work on another car then it’s the Tech 2 !!…like I said check the fuse and if good to verify and see if you have power to pin 16 at the DLC…it is hot with the key off…pins 4 and 5 are grounds so check with your multimeter between 16 and 4 and then 16 and 5 and see if you read system voltage…this will prove that both grounds are good !!..where did you read that the Tech 2 uses pin 4 for its ground ??…I could not find that fact.

 

I got the ground for the scan tool as being on pin 4 from a GM article regarding the Chevy Volt, which has two OBD ports, one on the driver's side and a second on the passenger's side. Both ports obtain power for the scan tool on pin 16 and ground through pin 4. Here is the article . . .

OBD2 (OBDII, OBD II ) Device FAQ | GM Volt Forum (gm-volt.com)

The pin reference is near the end of item 6 in the article, next to the last paragraph I think. I'm assuming there would be commonality for ground locations for all OBD 2 tools.

I have a set of factory manuals for the 2004 Corvette and have seen the same photo and read regarding the location of the RCDLR, but have yet to locate it on my car. I also note that the reference photo is showing the external antennas on the RCDLR, which are not on the receiver for the 2001-2004 cars. I removed the plastic cover accessible through the trunk but do not see the receiver from the rear. The Bose speaker is accessible from the convertible top door, and also has a plastic removable cover of sorts (I"m going from memory). I'm wondering if the receiver is located in this area on the convertible? Thanks for the assistance.

 

A bit more information . . .
Yesterday I noticed when I turned on the key the battery voltage shown on the DIC before starting the car showed 11.7 volts. I've been led to believe (and also do believe) the battery should be over 12 volts, especially when a fully charged lead/acid battery is in the neighborhood of 12.6/12.7 volts. So, wondering if this might be a source of my problems I drove to my local battery outlet, an independent who has been in the business many years to check it out. He put the tester on the battery and said there was nothing wrong with the battery, but it was only partially charged. Recommended I charge the battery on low amperage for a time, suggested overnight on a 2 amp setting. I did run a lead acid charger (old style, not smart) on the battery for 8 hours or so and after charging and settling down for 30 minutes or so before testing still showed 11.7 volts. I'm getting no error messages on the DIC and have no problems starting and running the car.

But, to charge the battery I disconnected one terminal while providing a temporary power supply of 12 volts to the auto electronics via the battery cables while charging the battery (in order to prevent loss of presets, etc.). This morning upon starting the car the Serv. Tire Mon. Sys DIC message was gone and the four tire pressure reading were blank instead of having the XXX where the pressure is normally displayed. I checked codes via the self diagnosing method via the DIC and no present codes exist. The only four are the previous four BO-RFA codes for the four TPMS sensors, 2100, 2105, 2110, and 2115 TPM Sensor Malfunction codes which were preset previously. There are no current codes nor any DIC error messages.

After about a 20 mile drive over a 20 minute continuous period still no codes nor error messages. I tried programming the TPMS system upon arrival back home, no response. I'm still attempting to get some local help reading the system with a Tech 2 that will read the systems required, but haven't been able to get the job done yet. I'll keep trying . . . . .

I'm still wanting to believe it must be the RFA receiver, but have only a hunch, no solid data that is obvious to me that it is the source of my trouble. I'm tempted to buy one just to install and see if it makes a difference or not, but haven't quite arrived at the purchase point yet. Hope I can learn a bit more before then, and hopeful I'll be able to see the darned thing to replace if and when it comes to that. I'm convinced it must be on the convertible top cover side of the left rear fender, I think I've thoroughly searched and photographed the remainder of the upper fender in the trunk area . . . . . .

Any thoughts, anybody . . . . . ???? BTW, everything else is working fine!

 

A fully charged battery is 12.66 volts (see chart below). The voltage you see on the DIC is NOT the same as when checking across the battery terminals with a multimeter…my DIC voltage reads .4 volts lower than the DIC (see pic below)…your battery is only 30% charged based on 12.1 volts !!…you may have enough juice to start the car but if the cars modules don’t have the proper voltage you can have issues…battery voltage is measured AT the battery…the battery when charged should be over 12.66..my voltage is 12.80 when left on a battery tender…if your battery does not charge to 12.66 you need a new battery…you want to make sure you don’t have a parasitic draw on your electrical system…check your battery voltage at the terminals and then check it overnight or 24 hours later…the voltage should drop only a little bit…you can get an accurate voltage loss doing a parasitic voltage draw test.You also should do a voltage drop test on the positive and negative sides of the charging system.

 

I didn't know that the DIC voltage was significantly different than a post to post check of the battery, good information to know. My battery is a couple of years old and I don't expect it to be in the range of a new 12.6 to 12.7 volt battery. I'll have to check the post voltage and see what that is.
Thanks!

 

I suspect that you are not one to throw parts at a problem and hope it works. I am hardly skilled enough to be giving electrical advice, but have a sincere desire to run my mouth. Perhaps it might help the group mind here effect a solution,

That said, If you do start throwing in parts hoping for victory, I wouldn't start at the receiver, which has a spotless record compared to the mischief consistently reported from a tired battery, or secondarily, bad grounds.

I would think that a battery driven to the test , on a car with an alternator, would test fully charged. Hopefully the problem is voltage related and not a mechanical problem. I am assuming this is a voltage problem, since it gave no warning before failure.

in reading here, the cars can be picky about electrical requirements, so a battery that arrives for a test with a low charge would be suspect, every car can be different in what it likes after all this time. it could be a marginal voltage at the receiver combined with a little age in the pressure sensors is enough to sever the wireless connection,

With a battery of known good function in your car , not one that can't pass a test without outside charging, if I were to start throwing parts, I would start with the wheel sensors. They are an unknown variable and can't be easily tested, so I would remove that variable .

If the everything else providing power checks out, they are the next in line, after the battery , as consumable parts as I view the chain. From new in 2014, with an expected ten year service life, they already have the majority of working life in the past, so you are not losing much money, if not functional, by replacing before the unknown future day of failure. It might be that old sensors radio output was marginal, and then one went low enough so that the receiver lost connection. I must admit, that doesn't sound very plausible, more likely it is the main power, since all four are reporting dead.

if you find a replacement alternator is the solution, the next part in my chain of failure, make sure to get an output the computer understands. Apparently most alternators listed as appropriate for the C5 are capable of a higher output than the original part. The car runs fine for awhile, but if the output signal goes higher than what the computer can understand, you get persistent running problems. You might already know that most C5 alternators are rebuilt , not replaced with new, because of this unusual situation.

I suppose the most constructive thing I might do is to wish you good luck. I hope you have some, with a simple solution , and will post the outcome so that others might learn what to do in a similar situation, the easy way. from the insight of others.

I did read one report of a new C7 corvette being overwhelmed by electrical interference at a Terrible Hurst gas station outside of los Vegas, and they couldn't start their car until morning and lights went out, The station has an electrical relay station adjacent, so had to be the same one I stopped out without any problems in a very electrically simpler Ford Explorer. This is in response to the suggestion of possible radio interference, which is commonly never mentioned as a problem with the C5.

 

Thanks to both of you guys, good points all! After my last post I put my charger onto the battery again and let it run until it topped out and shut off showing fully charged. I measured the battery voltage at the posts at that time to be 12.55 volts; giving it 3 hours or so of rest during which time the normal systems on the car were drawing whatever amounts of power they draw (security system, memory presets, and whatever else) I checked again and found it to be about 12.33 volts, just a little below the 60% level on C5 Diag's chart. I'm about to call it a day, but before I do I plan to go to the garage and check the voltage one last time before putting a trickle charger on overnight. The battery is about 2-3 months short of being 2 years old . . .
According to my parts guy replacement batteries normally don't last as long as original equipment batteries. I don't know if this is a true statement or not, but I do know he's speaking from several years of experience. I replaced the original battery on this car at 7 years of age (I was surprised too!) and never had any type of problem with the battery. It was replaced due to a map light on the car running down the battery, I found out the problem upon replacing the battery when its replacement also ran down overnight! Took a while to figure the problem out, had to keep a trickle charger on the replacement until the problem was solved.

strand rider, you may not be an electrical authority but you make some very good points in your comments that I'm taking to heart. You're right, I'm not one to toss money at a problem and the battery or grounds I agree are suspect. Perhaps if the battery doesn't come up nearer to snuff I might start there. My DIC voltage with the car running is in what I consider to be the normal range of 13.6 or 13.7, I think I have seen a low 14.0 or 14.1 over the years, not positive. I still want to get hooked up to a Tech 2 and see what it may be able to tell me. I appreciate your input regarding the spotless record of the receiver, that has given me second thoughts about its replacement.

I'm gone to the garage to check voltage now and to hook up the trickle charger, maybe a good night's rest will give me new insight tomorrow!!

Thanks guys!

 

OK . . . .

Checked the battery voltage at the terminals last nite about 10:00 pm, was reading 12.18 volts. Put my battery maintainer on and left it until 6:00 am at which time the voltage read 12.54 and the maintainer said it was completely charged. Left it off the maintainer until 7:30 and rechecked, voltage read 12.38 volts. Automatic hood light begins to draw down a bit of voltage upon raising of hood. Left it off of maintainer and rechecked about 1:30 pm, voltage reading was 12.43 volts, hood light did not come on this time for some reason.

Started the car and rechecked terminal voltage and DIC voltage, Terminal voltage was 14.6 and DIC voltage was 14.2, exactly the same difference as shown in Rob's photo and post above.

I think at this point I'm gonna give it a few days rest, decide which course of action to take, to include battery replacement. Heck, I may just drive without TPMS data, my old '66 seems to do fine without it, and since I've received no codes other than the TPMS ones mentioned above, may just give it and myself a bit more time . . . . . .

Thanks for everything to date guys, I'll repost should any new information become available!!

 

Yeah, you need four new sensors. Don't be like me and overthink everything. Happy Thanksgiving.

 

I think you may be right, I've not been able to do much with it since the initial post on the problem. With bad weather coming on, it's being driven less and less. I've tried unsuccessfully several times to reprogram the sensors with no luck. I've used several different magnets and would have thought that at least one of them would have been successful if the system was able to program, but so far no such luck.

One thing that has happened since the last post on the problem has changed . . . all four DIC tire pressures now read blank instead of XXX as originally displaying, and the Service Tire Monitoring System message no longer appears. Apparently somehow in my attempts to reprogram and display messages either I changed something in the system . . . . or it got tired of telling me repeatedly to service the system. In any event, the message is no longer displaying and no current trouble codes are setting in the system. I'm within a few thousand miles of needing to replace all four tires, so I think I'm gonna continue to drive the car as is until such time as I replace all four tires and TPMS sensors as well. Just keep an eye on the tire pressure the old fashioned way. I'll update the thread as the situation dictates . . . . .

Thanks much! And Happy Thanksgiving to All as well!!

Ron

 

This has been a great thread.

Thanks to all the participants.

I just had my TPMS sensors replaced with my new aftermarket wheels.

They all read 3-4 psi too high. Can this be adjusted via Tech 2 or in some other way?

 

Bill has had a broken leg in the last year or so, and also moved. He's not as "forum active" as he once was. Good idea to PM him, he may help you out. Good luck.......

 

This thread I found very interesting. I just purchased a C5 (1998) this past Tuesday but the remotes do not work and I an getting a TPMS error on the dash. Now I have some things to check.

 

OK, time to do a bit of updating to this thread, been a while . . . . . .

Refresher . . . . . I replaced the original tires and TPMS senders in the wheels of this 2004 Corvette back in September of 2014 with matching new original TPMS senders as were installed at the plant. The tires were replaced with Hankook that were not run-flats, trying to get away from a bit of the tire noise, and all worked well. Until September or October of 2021 when suddenly all four tire readouts in the DIC panel began reading XXX as the tire pressure. All four failed and began this readout simultaneously, which made me a bit suspicious that it was a battery problem in the TPMS senders since I don't expect all four to fail at the same instant in time . . . .

After going through all the information I was able to gain from previous posts, I was still left with the belief that something in the TPMS channel itself in the car was at fault rather than the TPMS sending units. I decided to go along with the failed readout until such time as when I was replacing tires and TPMS sensors again to see if I could at that time figure out the problem . . . . . tires probably have another year or two of life in them based upon my driving mileage.

And then someone on the forum stated he had the same sensors on his car for the past 22 years and they were still working properly. That statement was backed up by at least one or perhaps two other forum members regarding the life of their sensors, in the same range and still working. Got me to thinking . . . .

I still had the originals removed from the car back in 2014 and all were still functioning properly when they were removed. Following are pictures of the four originals showing date codes. Notice that the date codes on these originals range from March or April of 2003 to July of 2004 or so. A good 18 years or so older . . . . . .








So, on a whim I took the four out to the 2004 Corvette that I had tried unsuccessfully at least a half dozen times to reprogram the replaced TPMS sensors still in the wheels. I left those in the wheels, but laid the four 18 year old originals on the convertible top and set the car into the TPMS learning mode. I took my circular magnet in series from the first to the fourth of the originals and each successfully programmed with the vehicle! Much to my surprise!

I don't have a record of manufacture dates for the replacements now in the wheels, but I do remember being aware of being sure that I received newly dated TPMS sending units when I purchased them and am satisfied that they were within a year or two of the 2014 date that they were purchased. Go figure . . . . .

The long and the short of the matter is that I don't believe that the car has a fault in the TPMS system, the problem lies with the sending units, although why all four would simultaneously start transmitting the XXX pressure reading is beyond me. I plan to purchase four new sending units and to install them into the present tires I have on the car. They should still be good for the life of the next set of tires I have to purchase in a year or so, I'd think. And I don't see any logic in reinstalling the original TPMS sensors that I currently have, they'd probably only fail as well within the next year or so. I think part of the reason they're still functioning is because they have been sitting idly "in storage" since removal and haven't been called upon to do any transmitting to speak of.

So, I think my problem is cured, or at least on the way to being cured . . . . . . any thoughts?? Thanks to all who contributed comments and suggestions, just wanted to post this for anyone's future benefit who might have the same or a similar experience.

Ron