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Discussion Starter · #1 ·
I recently bought a 2004 base convertible with 36,000 miles. It ran great...for a month. Just changed oil, oil filter, and air filter. Drove it for three days, no problems. Yesterday...started and ran fine, stopped at the hardware store, went to restart and...
--"Reduced engine power"
--Codes P0101, P0412, P0418, P0443, P0645, U0107; TCS C1278, C1282

I started it three or four times with the "reduced engine power" as a result. I got it to start one more time at full power, but check engine still showing and got it home. It hasn't started since. I visually checked the MAF sensor: not bad, but I cleaned it. MAF wires look good, although I did not test them. I visually checked the throttle body...nothing obvious. The throttle body does click non-stop when the key is in run position, but the engine is off. Also, butterfly valve does not move when accelerator pedal is moved with key on.

I do have an appointment for the C1282 fault next Wednesday. That came on earlier and slammed on the front, right brake during a normal highway cruise. I'll have to flatbed the car to the mechanic if I can't figure this issue out. I've replaced MAF sensors before, but that was the only code that was showing on those cars.

Any ideas? Thank you!
 

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DC PIT CREW BOSS
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Your list
P0101 Mass Air Flow (MAF) Sensor Performance
P0412
P0418 Secondary Air Injection (AIR) Pump Relay Control Circuit
P0443 Evaporative Emission (EVAP) Purge Solenoid Control Circuit
P0645 Air Conditioning (A/C) Clutch Relay Control Circuit
U0107 Lost Communications With Throttle Actuator Control (TAC) Module
C1278 Steering Position Sensor Circuit
C1282 Yaw Rate Sensor Bias Circuit Malfunction


With that much it look like you are on the right track by getting some0ne with a Tech 2 to rn the diagnostics
 
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Discussion Starter · #3 ·
Copy. Unfortunately, now I need a flatbed to get it to the mechanic.... :sneaky:
Thanks for the note and for your separate welcome.
 

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Discussion Starter · #4 · (Edited)
Torch,

Believe it or not, I solved the problem. A little bit of a story (as always, I guess)....:

Although this had nothing to do with the problem, but everything to do with solving it, I'll start with this--one of the key fobs didn't work when I bought the car, so I ordered a new one. It came in after the car had stopped running, but I took it out to the garage and paired it to the car. I figured I'd check it's operation by pushing the buttons. Lock, check. Unlock, check. Trunk release, check. Alarm...no check...but I could hear the relay clicking. I swapped that relay with another identical relay and the alarm worked fine. That got me to wondering what other relays or fuses may be bad.

(At this point, let me add this: The guy I bought the car from told me he had put a new battery in, but as I was reading up on all of the codes, I saw several mentions of bad batteries maybe being a cause. I checked the battery that he had put in and it was a real "no name", as in there was not even a sticker on it. I replaced it last Wednesday with an Optima red top after the car wouldn't fire up, although it would turn over. I will mention that when I replaced the battery, I found that the terminal connector was not and could not be tightened adequately on the negative terminal on the no-name battery.)

I checked all of the fuses; they were fine. I switched one of the fan relays with the ignition relay and, after three days of "no start", she fired up immediately when I turned the key! I replaced the ignition relay and the alarm relay and all is well. All engine codes cleared and the car runs perfectly. My suspicion is that the lousy, new battery and its inadequate negative terminal connection screwed up those relays. Out of an abundance of caution, I will replace all of the other relays in both fuse boxes. The new Optima battery and the new fuses will cost about $325, but I feel like I dodged a bullet. Thank goodness I spent the $12 on the new key fob, which led me to find out that the alarm relay was bad.

I cancelled the flatbed, but will keep my appointment with the mechanic on Wednesday, because I do still get C1278 (TCS Temporarily Inhibited By PCM) and C1282 (Yaw Rate Sensor Bias Circuit Malfunction). (I wonder if the lousy battery screwed that up, too....) If the car hadn't tried to shove me into another lane of traffic at 78 mph by slamming on the front, right brake the first time that code came on, I would just replace the yaw rate sensor myself, but I want to make sure there are not any other problems and want a pro to take a look at it.

Just thought I'd share this in case it might be of help to anyone.

Mojo
 

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Good job. That gives you a good sense of accomplishment
 
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Discussion Starter · #7 ·
Yeah, the Yaw Rate Sensor thing has me concerned. If I can figure it out, I'll let you know! Thanks.
 
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