WOT, c0242 code, REP mode, T/C light
09-08-2012, 09:52 PM
#1
WOT, c0242 code, REP mode, T/C light I just got my car back from the tuner, and while breaking the engine in, I was sporadically getting reduced engine power mode, my T/C light came on, and my car would still when I let off the gas. We chalked it up to the tune... the car was calculating too much air for the TPS, and it thought the butterfly was stuck open, so we thought. I was also throwing a code for the steering wheel position sensor.
Changed the parameters in the tune, and he noticed a voltage drop in the car, right as REP mode kicked on. They couldn't dyno the car, it would randomly do this, well, they hooked up a battery charger, and it went away completely.
I should note that my battery light isn't on, my DIC reads 12.8 volts battery OK, but, the car sat for a little over a month with the battery connected (accidentally), and TBH I think I left my interior lights on to completely drain the battery (motor swaps are a pain in the dick).
So here's what I'm asking: in your opinion, do you think the EBCM, and SWPS both went bad simultaneously, or do you think I have a voltage issue? I feel like I may have a dead/dying battery, if not an alternator.
Changed the parameters in the tune, and he noticed a voltage drop in the car, right as REP mode kicked on. They couldn't dyno the car, it would randomly do this, well, they hooked up a battery charger, and it went away completely.
I should note that my battery light isn't on, my DIC reads 12.8 volts battery OK, but, the car sat for a little over a month with the battery connected (accidentally), and TBH I think I left my interior lights on to completely drain the battery (motor swaps are a pain in the dick).
So here's what I'm asking: in your opinion, do you think the EBCM, and SWPS both went bad simultaneously, or do you think I have a voltage issue? I feel like I may have a dead/dying battery, if not an alternator.
09-08-2012, 10:12 PM
#2
My first guess would be a weak battery and/or bad connections. I would put in a known good battery and double check the battery cable connections. Remember, the problem that develops with the battery connections (and the rest of the grounds for that matter) is oxidation. The oxidation just makes the metal look dull and appears to be harmless - but it ain't. You should take flat file, points file, or emery paper and make the grounds shiney. In addition the battery ground, I would shine up the ground underneath the hood strut and the 3 grounds on the back of both heads.
Finally, if your alternator is bad, you should be able to make the inside dome lights dim by turning on the AC, fans and other accessories. In fact, without some alternator amperage the engine will eventually die when all the accessories are running.
Finally, if your alternator is bad, you should be able to make the inside dome lights dim by turning on the AC, fans and other accessories. In fact, without some alternator amperage the engine will eventually die when all the accessories are running.
Last edited by Darkman; 09-09-2012 at 10:26 AM.
09-11-2012, 09:12 PM
#6
just a quick heads up guys, I think I resolved the issue.
I ran a ground strap from the main ground (under the hood strut), to the - of the battery, and the - of the battery to the ground on the back of the head. lights seem a hair brighter, starting is faster, and most importantly, i'm not throwing the code. when I feel like it, I'm going to run another one from the DS head over to the strut tower just because i'm a real bad idiot.
I ran a ground strap from the main ground (under the hood strut), to the - of the battery, and the - of the battery to the ground on the back of the head. lights seem a hair brighter, starting is faster, and most importantly, i'm not throwing the code. when I feel like it, I'm going to run another one from the DS head over to the strut tower just because i'm a real bad idiot.
09-11-2012, 09:28 PM
#7
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I had a REP issue with my Silverado SS and it was a loose ground. I literally turned the bolt 1/2 turn and it was OMG tight at that point. It has never happened again and that was 4 years ago.
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09-12-2012, 06:56 PM
#9
This is a long shot, but how's your fuel pump doing? When I was installing my Walbro and the Racetronix hotwire kit, I got a better feel for the way the fuel system works and theorized that a faulty or blocked return valve or severely degraded fuel filter could stall the fuel pump, resulting in a short burst of massive current draw.
Backing way up, is there ANY pattern to this at all, or a series of tests that we could devise that will test each critical fuel and ignition component in series?
Backing way up, is there ANY pattern to this at all, or a series of tests that we could devise that will test each critical fuel and ignition component in series?
09-12-2012, 07:39 PM
#12
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How can it not throw a code? Something is causing it to go into REP mode. Have you done anything different to the throttle body? If there is a mismatch in resistance between the TPS sensors that will do it. Did you pressure wash the engine? Water in a connector will cause it. Triple check all connections especially at the starter and anything else you messed with when you changed the engine. Make sure you did not smash or crimp any wiring when installing the engine.
09-12-2012, 07:50 PM
#13
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That Code is a ABS code. Did you bump/loosen the ABS module in the front of the car? Here is a link where they talk about the problems they have with ABS/stabilitrak controllers http://forums.corvetteforum.com/c5-t...ir-1214-a.html
09-13-2012, 02:27 PM
#14
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If the diode trio is going bad inside the alternator, AC voltage can bleed into the system and wreak havoc. The EBCM and SRS (airbag) are the most sensitive modules on the car and are usually affected the most.
I would also try another battery...as I have said before, if the batteries internal resistance gets too high, you will have these issue's even though they would not cause these problems in older vehicles. It takes a really expensive tester to measure this.
I would also try another battery...as I have said before, if the batteries internal resistance gets too high, you will have these issue's even though they would not cause these problems in older vehicles. It takes a really expensive tester to measure this.
09-14-2012, 07:18 PM
#15
I still have the red top, tried a few pulls with an autocraft battery and it did the same as the Napa and optima.
Where is the ground for this module? I scanned in front of the radiator and searched for pinched wires but didn't find anything.
Where is the ground for this module? I scanned in front of the radiator and searched for pinched wires but didn't find anything.
09-14-2012, 07:25 PM
#17
09-14-2012, 07:49 PM
#19
Another thought: is it possible that you have a dud throttle body? I'm just recollecting the REP issues that people had due to poor throttle body porting jobs. Either the throttle body came back DOA, or it failed weeks or months afterwards.