Dalannex

Old key = 1.33 ohms
New key = 0.391

So this explains my problem then?


-Justin

BlackZ06

Yup ..... they have to be a WHOLE lot closer than that .... BUT you say your wife used the new key and it intermittently worked ?????

Did you clean the VATS pellets with a pencil eraser and some alcohol as I posted earlier ??? If you put the "new" key in, what happens to the SECURITY icon when you move the key to the START position ????

The BCM controls the two security systems (content theft deterrent and vehicle theft deterrent) When the key is moved to the ON position the SECURITY lamp should go out as it is displaying the status of the CTD system. When you move the key to START the SECURITY lamp is showing the status of the VTD system. If the lamp is on or blinking (which I'm betting it will be) ... then DUMP THE CODES and the VTD will tell us if it is the key that it is unhappy with.

We're trying to help you ... but you gotta help us .... DUMP THE CODES .......

Dalannex

Yes I did clean the contacts on the key before I checked resistance. I also used 2 different DMM's and got the same measurements.

I went out and tried both keys while watching the security light. With the old key in the ignition and turned on the security light went out. With the new key in the ignition and the key turned on the security light flashed. So that assured me that the key is a problem. Then I checked the codes.

40 BCM:
B2721 H C Pass key detection circuit
B2723 H Pass key detection circuit

58 SDM:
B1001 H Option configuration error

A0 LDCM:
B2282 H Battery circuit #1
B2284 H Battery circuit #2
B2262 H Mirror position signal circuit
V1064 H
V1096 H

A1 RDCM:
B2283 H Battery #1 circuit
B2285 H Battery #2 Circuit
V1064 H
V1096 H

B0 RFA:
V1096 H
V1064 H
V1016 H
C2115 H

So I would say that the key certainly is the problem. And some codes were from switching the battery. Now, what do all the the suffixes mean? I mean these:

PCM - powertrain control module
TCS
RTD
BCM - body control module
IPC
RADIO - obviously radio
HVAC - heat/ventilation air conditioning
LDCM
RDCM
SCM
RFA

This is really great information. I will hook my laptop on my 81' and tune on it all day long but until this problem was scared to touch the C5. I'm ready to get after it now.

BlackZ06

OK - easy one first .....

PCM - powertrain control module
TCS - Traction Control System (EBCM)
RTD - Real Time Damping (F45 option or F55 option)
BCM - body control module
IPC - Instrument Panel Cluster
RADIO - obviously radio
HVAC - heat/ventilation air conditioning
SDM - Sensing and Diagnostic Module (Airbag -SRS system) <---- You missed this one
LDCM - Left Door Control Module
RDCM - Right Door Control Module
SCM - Seat Control Module
RFA - Remote Function Actuator (key fob and TPMS receiver)

dgrant3830

Since you have all the codes recorded, I'll suggest that you clear them all using the "Reset" button, then using the old key, see if you have any other problems or the original no-start issue come back. I agree that your new key seems suspect but I don't know what the allowable tolerance is.

BlackZ06

OK, now for the codes ... I'm gonna do the easy ones first ....


A0 LDCM: Left Door Control Module
B2282 H Battery circuit #1
B2284 H Battery circuit #2
B2262 H Mirror position signal circuit
V1064 H First Letter is "U" as in "Uniform"
V1096 H First Letter is "U" as in "Uniform"

I'd delete all these codes. The Uxxxx codes are pretty common in a Corvette. They are posted when one computer on the network cannot communicate with another computer at a certain moment in time. The network is slow by today's standards (think dial-up speeds) and there is a lot of data moving around .... so unless there is another reason to study a Uxxxx then delete it.

The Battery Circuit codes and the mirror postion code are also History. Let's delete them for now as they are probably the result of a low voltage condition sometime in the past. If there is a real problem the DCM will re-post the code and we'll address it later

A1 RDCM: Right Door Control Module
B2283 H Battery #1 circuit
B2285 H Battery #2 Circuit
V1064 H First Letter is "U" as in "Uniform"
V1096 H First Letter is "U" as in "Uniform"

Same as with the LDCM, let's go ahead and delete all of these for now. If there is a problem, the DCM will re-post a code.

B0 RFA: Remote Function Actuator - This is the radio receiver for your key fobs and also for the Tire Pressure Monitor Sensors (TPMS). It commands the IPC to display LOW TIRE PRESSURE and other appropriate messages. It also passes along to the BCM the data when a key fob is used to LOCK/UNLOCK the car.
U1096 H
U1064 H
U1016 H
C2115 H Left Rear TPM Sensor Malfunction

Once again let's DELETE the communication codes (Uxxxx). Looks like at one point you had a problem with the LR TPMS. If the problem is fixed let's delete it. Otherwise if this is a problem, you can leave it and we'll come back to it later.

58 SDM: Sensing and Diagnostic Module - Often referred to as SRS (Supplemental Restraint System). This module ihas a decelerometer in it that is used to decide if/when to fire the bags. The module stores its own power so it can fire the bags even if the electrical system fails during a wreck. TREAT WITH RESPECT. The SRS is the only "safety" system I know of that the Federal Govt REQUIRES a WARNING label for .... it can kill you .....

B1001 H Option configuration error

One other function of the SDM is that when it fires the bags it is permanently LOCKED and stores the last 5 seconds of vehicle data for later crash analysis (vehicle speed, deceleration rates, throttle position, brakes on/off, etc.). The SDM is programmed with your VIN, and a BCM parameter called PROM_ID. If any of the three computers is changed, this code will be thrown until the computers are properly programmed with VIN and PROM_ID. This is a possible indication that the cars airbags fired sometime in the past. If not, either the BCM or the PCM has been replaced since the car left the factory. If this is a CURRENT issue, your AIRBAG warning light will be ON when you are driving the car, and the SRS is disabled. If you are not having this problem, DELETE the DTC B1001.

40 BCM:
B2721 H C Pass key detection circuit
B2723 H Pass key detection circuit

Maybe I should leave these two for Bill Curlee .....

The B2721 - The short and simple answer, the PASSKEY resistance in the key does not match the expected reistance programmed in the BCM

The B2723 - Same again, the resistance doesn't match. BUT, the system is also detecting a "short" or "open" curcuit. It is possible the "new" key is really bad and actually appearing "open" at times ... don't know if that's possible .... Bill's the guy to answer that one .. he's the ignition key/lock expert .....

dgrant3830

The codes are wonderful things to be able to see. Sure wish they had them on the C-6's too.

BlackZ06

You gotta know that was INTENTIONAL taking away the ability to display the DTC data ...... what I can't figure out is WHY ??? Do the dealers believe they get less repair work because we can work on the cars ?? I would doubt it .... how many TOTAL Corvette owner's do significant work on their own cars ??? While it might seem like a lot on the Forum, don't forget Chevy made about 250,000 C5's during the generation's production run. I'd be surprised if 10 percent work on their own cars.

So what was GM afraid of ??? It has to be something else because, again, they INTENTIONALLY took away the function.

Dalannex

Thanks a lot. That option configuration error is really interesting information. I'm not having any problems with air bag lights or anything like that so I deleted the codes. I'll keep an eye on it I guess. I forgot to mention that I do have a bad left rear wheel sensor so that code is good. I need to get the car in and get that tire off and replace the wheel sensor. The other 3 program just fine but that left rear won't program no way no how so I assume the batteries are dead. The car had new tires put on when I bought it too and that left rear one leaks so I will get that fixed too. Thanks for all of the great information and help.

Now I'll see about getting a different key with the right resistor in it then move on to the recent driver seat malfunction.


-Justin