[laynlo15]

I had to drive to Columbia Mo yesterday to pick up a belt for my Commercial Mower, been waiting for one from my dealer, Oreilly's crossed referenced one and I went to pick it up. Car ran fine till I got to Columbia, I was go thru a round about and when I came out of it I applied some throttle and peddle was dead, check engine light showed up on the dash. Luckily I was just a 1/2 mile from Oreilly's and limped it there. I didn't have my computer with me to check the codes so I had them scan it. Here is what showed up.

P0178 FF sensor low circuit
P135B Ignition Coil Supply Voltage Circuit 2.

They tried to reset the code and no go. I had my wife come and bring my HPTs so I could check and possible reset, nope. My Chevy dealer was less then 3/4 mile away so I limped it over there, luckily there were some painters there I knew so they opened the door so I could leave my car for Matt Jennings to check out, he's helped me do a few blowers and is really good at diagnosing electrical issues. Its a DSX sensor which I haven't heard of anyone having issues with them and the sensor has been on the car since February of 2022. Not sure what's going on but guessing it's got to do with the coil. I believe the sensor gets it signal from the number 6 coil so I'm guessing the issue starts with that coil.
Has anyone else had this issue?

[cjperformance]

I'd pull the ECU connector and make sure your FF terminal is still seated, and/or make sure there aren't any breaks in the wire... mine came with a dinky little wire with minimal insulation. Been on my list to do something better with it. Also check the other connectors too on the FF connector and coil too.

Pin may have backed out if not seated correctly....

Here's another thread:

https://www.camaro6.com/forums/showthread.php?t=589879

[KingLT1]

I would think it's something to do with the wire at the ingition coil. If the ECU loses signal from the flex sensor it defaults to a E40 stoich ratio and should still run "ok".

[laynlo15]

It would barely run like all the coils on that side are dead. I just saw a Lt4 Corvette guy on that forum who had the exact same thing just happen. He pulled the Fuse box and checked all the pins and found out some were dirty, cleaned it up and put it back together, runs just fine now. I think it could be a ground, a buddy of mine where we dyno had this happen when he put his 2300 on, all four coils on bank 2 were not firing. He hooked up another ground from the lug by the fuse box and ran a ground wire to the head. Fired right up and ran great after the ground wire. Its not just one coil, I've had those go bad before and it always ran with just a miss, this baby won't run hardly at all, could barely get it above idle to get it to the dealer, same with the Corvette guy as he could barely keep his running.

Here is his post on the Corvette forum.

p135b - Ignition Coil Supply Voltage Bank 2

The car barely runs. It feels like it's running on 4 cylinders which may make sense if Bank 2 isn't getting any voltage. I checked the fuses and they're fine. I'm at a loss of where to look for what. Any suggestions?


Thanks guys. Figured it out. There was a poor connection between the main fuse block and the harnesses under it. Cleaned up the pins and the problem seems to be solved. Kinda a mystery as to why this is the case. The car has 20k miles and has never even been in the rain. But whatever, it’s running strong again.

[laynlo15]

Originally Posted by cjperformance

I'd pull the ECU connector and make sure your FF terminal is still seated, and/or make sure there aren't any breaks in the wire... mine came with a dinky little wire with minimal insulation. Been on my list to do something better with it. Also check the other connectors too on the FF connector and coil too.

Pin may have backed out if not seated correctly....

Here's another thread:

https://www.camaro6.com/forums/showthread.php?t=589879

I can't imagine it coming out and with the ignition coil codes I just don't think that's what is happening. If the coils are not firing on that side the FF sensor is not going to work. That one has been plugged in to the ECU for over 1.5 years, it was fine when Mike pinned the Reflex about a year ago and it hasn't been apart since then. It's got to be in the coils, ground, fuse or dirty pins under the fuse box. I'll find out tomorrow and give and update.

[Dirtbike]

Flex Fuel sensor is probably getting power from the #6 coil, not signal. I dont care for FF harnesses that leech power from an ignition coil for issues exactly like this. I'd rather it pull power from the evap like the gen5 diy harness. My guess is something grounded out or shorted from the coil to the FF sensor, dropping out power to both devices - which would explain the codes.

[laynlo15]

Originally Posted by Dirtbike

Flex Fuel sensor is probably getting power from the #6 coil, not signal. I dont care for FF harnesses that leech power from an ignition coil for issues exactly like this. I'd rather it pull power from the evap like the gen5 diy harness. My guess is something grounded out or shorted from the coil to the FF sensor, dropping out power to both devices - which would explain the codes.

I stand corrected on the signal, power would be correct. But, that doesn't explain all the coils not firing. I'm sure it is just running on bank one. I'm still convinced its a ground and agree with you on that but its affecting all coils on bank 2. I'll know in a couple hours.

[jlaudio11]

I'm thinking the flex fuel sensor or wiring going to coil is pinched, shorted etc. Did it ever come out of limp mode? Going through the process of tuning my car after the turbo set up, i managed to piss it off a few times and send it into reduced power mode, whole car would shake and act like like it was only running on 4 cyl, reset the dtc and it would immediately come out of it.

[laynlo15]

Originally Posted by jlaudio11

I'm thinking the flex fuel sensor or wiring going to coil is pinched, shorted etc. Did it ever come out of limp mode? Going through the process of tuning my car after the turbo set up, i managed to piss it off a few times and send it into reduced power mode, whole car would shake and act like like it was only running on 4 cyl, reset the dtc and it would immediately come out of it.

It actually never went into limp mode or reduced power mode. It was shaking because it was running on just Bank 1, just had no power when it happened. So, I guess my title was wrong when I said limp mode.

[laynlo15]

So Matt had a chance to check everything over and it was the 15 amp fuse which is number 64 in the fuse box, number 62 is Bank 1 FYI. After he replaced the fuse he also checked all the wiring back to the sensor and at coil 6. Nothing apparent to the eye, pulled the plugs apart to check those including at the FF Sensor, traced all the other wires to the fuse box and harness, pulled the fuse box to check to make sure all was good at the ECU. Nothing was wrong there. It's a mystery but running great now. As said in one of my other posts, the FF sensor has been on board since 2/2/2022 so we just don't know what caused it. I'll carry my extra fuses and always carry my laptop with me to read codes if it ever happens again, hopefully not. Modifying cars has it benefits and obviously there are some downsides to it also. No issues till this and I have almost 9,000 miles miles since it was installed and 4,000 with the Maggie and TooHighPsi PI. So, go figure.

[jlaudio11]

It's been pretty hot in Indiana the last few days, not sure how it's been in Missouri, how far the drive was or how far you drive it regularly but did something just get really hot? I know my aluminum intake can heat soak pretty good on long drives and take awhile to cool off.

[laynlo15]

Originally Posted by jlaudio11

It's been pretty hot in Indiana the last few days, not sure how it's been in Missouri, how far the drive was or how far you drive it regularly but did something just get really hot? I know my aluminum intake can heat soak pretty good on long drives and take awhile to cool off.

I had just driven it 35 miles so I'd say the IAT's weren't very high, probably 100 or so. It was between 75 and 80 degrees and after the trip all being hwy and just running along about 30 miles per hours after I went thru one of the round abouts don't think that was an issue. The day before I went to a car show and when I came home it was 95 degrees and didn't happen then so something freaky happened but hope to not duplicate it again. It was low 90s yesterday until a storm blew in last night and right now it's just 71 and it is supposed to be on 77 today. We've had several heat waves since mid July and got really hot just a couple weeks ago when it was over 110 heat index. Sucked.

[rcoe]

Originally Posted by laynlo15

So Matt had a chance to check everything over and it was the 15 amp fuse which is number 64 in the fuse box, number 62 is Bank 1 FYI. After he replaced the fuse he also checked all the wiring back to the sensor and at coil 6. Nothing apparent to the eye, pulled the plugs apart to check those including at the FF Sensor, traced all the other wires to the fuse box and harness, pulled the fuse box to check to make sure all was good at the ECU. Nothing was wrong there. It's a mystery but running great now. As said in one of my other posts, the FF sensor has been on board since 2/2/2022 so we just don't know what caused it. I'll carry my extra fuses and always carry my laptop with me to read codes if it ever happens again, hopefully not. Modifying cars has it benefits and obviously there are some downsides to it also. No issues till this and I have almost 9,000 miles miles since it was installed and 4,000 with the Maggie and TooHighPsi PI. So, go figure.

At least you found the issue, hopefully it won't happen again but if it does you know exactly where to look. On a couple of my problems got them fixed but could not pinpoint the cause.

[laynlo15]

Originally Posted by rcoe

At least you found the issue, hopefully it won't happen again but if it does you know exactly where to look. On a couple of my problems got them fixed but could not pinpoint the cause.

Glad you got yours lined out also. We just keep rolling on.