Dan H.

It looks like my nannies are disabled because of these. Thoughts on what these could be? Am I ok to go out if I limit myself to 5/10?

I've found the 1284&5 are the accelerometer under the passenger seat. I tried unplugging and plugging, but no change.

MySR71

Is there any chance the accelerometer is installed backwards?

JerryTX

Nannies disabled is not a bad thing if you have been doing this a while. If your relatively new to this go drive 8/10.. if you have been doing it a while, go 9/10s and creep up on good car control in the absence of a nanny to save you. Driving 5/10's sounds about like what I drive on the street.

Dan H.

The plug socket on the accelerometer is facing the passenger door. I'm pretty sure that's how it was mounted to the floor, I could be wrong though.

I've driven it to work and around town with no issues.

AzMotorhead

Really Need to know if there was a letter in front of the numbers.
P B C or U
Just the number alone is nothing

Bill Dearborn

C1214 on a 2001-2004 C5 is a fatal error. It means there is a high likelihood the power relay for the BPMV power located in the EBCM has a high resistance. The code could be caused by several things that all mean a reduced voltage level at the motor in the BPMV.

Since you have more than one fault code associated with the EBCM make sure the electrical supply is in good shape. Fuses, wiring, connectors, battery, battery connections and grounds. If that is all in good shape then look deeper.

The EBCM has two different power and ground circuits. One circuit provides power to the EBCM electronics and the other provides power through the relay to the BPMV. C1214 is related to the second one. If the motor in the BPMV has an internal high resistance short this will reduce the voltage available to run the motor and trigger the code, since the short draws added current it can burn the contacts in the EBCM and reduce the voltage even more. A loose ground on the ground side of the BPMV can also cause the issue along with a blown fuse, poor +12V electrical supply to the EBCM or just a problem with the relay. Potential solutions go from replacing a fuse, replacing the battery fixing a loose ground, replacing the BPMV, replacing the EBCM, replacing both the BPMV and the EBCM. One substitute for replacing the EBCM is to send it to a shop that will replace the relay. However, even though you do that and the code goes away you still need to make sure the BPMV motor doesn't have a high resistance short. If it does the relay fix will not work long as the motor may continue to degrade and draw more current. Since there is an internal short in the motor it also means the motor will not perform correctly and the ABS, TC and AH operations could be compromised.

Several people including myself have posted the Diagnostic Procedure for checking C1214 in the C5 Tech forum. Most people don't bother checking to see if the BPMV needs to be replaced as the procedure indicates, they just send in their EBCM to get the relay replaced and just try to get the light to go off. They are just happy having the light off and don't really care whether the system will work optimally any more.

Bill

Dan H.

Bill,
Thank you for taking the time to write up that post, it is extremely helpful and I know the source is knowledgable and well respected.

I tried to find your procedure and I was not able to, I did find some others, I will search some more for yours. We celebrated our anniversary and mothers day this weekend so this is my first time back on the computer.

When things go haywire, i look to where my hands have been in the car. I re-routed the front wheel speed sensor wires installing brake ducts, I'll poke around there. I also cracked the base of the yaw sensor when i removed it from the stock location, it is plugged in, but the wire was somewhat tight from the hole in the carpet. I only had the access panel off where the computer is in the passenger footwell, i can't seem to get it back on solid.

Does anyone know where to buy the yaw sensor (or accelerometer)? I don't see it on rockauto.

Looks like the relay is easy enough to replace using one of the DIY's I saw. I'm comfortable soldering electronics.

I did drive the car several times prior to the event to make sure all my work was good to go. I was surprised to get an error after the number of miles i drove.

aaronc7

I have a 03 Z06 and had intermittent C1214 code. I could usually clear it out after I started driving the car. I replaced the battery at some point and the codes more or less stopped. The day of my first track event ever I got the C1214 code and could not clear it. It stressed me out a bit at the time, but I made it thru the 2 day event just fine with no TC, AH, or ABS. As Bill described, it was a power issue in the EBCM, I resoldered the 5 joints to the relay and all the lights went out/everything went back to what appears to be normal function. I didn't know about checking the BPMV motor as well, might have to do that one day.

I'd say don't stress it in the meantime and just drive a bit more conservative if that makes you feel better about it.

Bill Dearborn

I will try and find the one I posted. It is buried in the C5 Tech session in the 2007 to 2008 time period.

Update: I couldn't find it with a search. Search function on my name only gets me back about 4 years. There were tons of threads and posts on the C1214 code in the 2006 through 2009 time period. Both the EBCM and BPMV had to be replaced on my 03 back in 2007. The cost was covered under GMPP at the time but when I asked the mechanic why he had replaced the BPMV he told me it had failed the resistance test. That meant it had showed some amount of measurable resistance VS infinity.

I am attaching a Word document to this post which contains the diagnostic procedure, diagrams, schematics and connector end views.

Bill

Dan H.

Strange update
So last weekend was my anniversary and mothers day. Today was my first chance to mess with the car since the track day. I cleared the codes assuming they would come back on instantly. Oddly enough, they did not come back. So I went and washed off the 120mph bug splatters and took it to the back country roads. Was able to confirm that traction control activated and worked. Also confirmed that active handling activated and worked. Didn't get to test out the ABS yet.

Leaves me uncertain what the cause is. I was prepared to pick up a new yaw sensor and to go through the EBMC evaluation process which seems to usually lead to repair. Should I still do both of these fixes?

I'll probably start driving it to work a few days a week just to get more miles on it to see what happens. Would rather not spend the $280 on those parts if its not needed. I do have Watkins Glen at the end of June and want to be confident going into that event.

Bill Dearborn

If you usually run with the nannies off you may never miss it. My 03 got the C1214 code while at the track and I didn't have anything. The only problem I had was with Heel and Toe downshifting. It turned out that I wasn't blipping the throttle enough and under hard braking as I let out the clutch the ABS relaxed the rear brakes just a little to keep the rear wheels from locking up. When I went into T1 the first time without ABS and let the clutch out after downshifting I got a good chirp from the rear tires and some sideways motion. That is when I realized I had to rev the engine high enough so I could hear it over the normal on track wind and tire noise.

The only other times I used ABS at the track was when I ran over something (like power steering fluid) in the braking zone that reduced track grip.

Bill

Dan H.

UPDATE
So originally I was able to clear the codes out. I went out and drove it around, got all the systems to activate and work. I then started my maintenance for my next DE and when I was done, only the 1214 code came back on and could not be cleared. I followed the procedure that Bill D sent and is attached above. My ground was good and my fuses were still in tact.

At this point I pulled the EBCM and shipped it to ABSfixer. The repair was done quickly and shipped the same day. They do a nice job with email status updates on the job. I installed the repaired EBCM and cleared the 7 codes I had from driving it without the EBCM installed. All lights stayed off when i started it up. The next day I drove it to work and back which is approx 70 miles and still no lights or codes. I would have liked if ABSfixer had confirmed that there was an issue.

Thanks to those that helped me. Wanted to close the loop on my post to help others who may encounter this same issue.

Will be at Watkins Glen Friday, hope to have the nannies