Limp Mode Need Help

[Stealth78]

Last week I was approx 50 miles from home and while doing a strong highway pull the car went flat on its face in limp mode. My first thought was maybe false knock...? I pulled off of the highway, all gauges were reading fine, gave the car my best visual inspection that I could at the time and could see no obvious problems. The car did have an engine light on and the voltage light was blinking (voltage was reading fine). I decided to shut the car off and see what would happen as in limp it would not allow me to go over 2,000 rpm's. After letting the car sit for a couple minutes I restarted the car, the voltage light was not blinking anymore but the engine light was still on, although the car returned to full power. I drove the car home with no signs of anything being wrong, the engine light was then gone as well. Haven't driven the car much for the past couple weeks but a few short trips, had not had the problem again so I assumed it was indeed just a false knock.

Here we are two weeks later, yesterday I just installed my underdrive pulley, Woodhouse trans mount, Random Tech mids with hi-flo's and a Corsa cat-back. Didn't drive the car more than 3 miles and when attempting to make my first strong pull the car when into limp mode again. My first assumption was "It has to be false knock from all the extra vibration from the Woodhouse trans mount" (which is A LOT of vibration in the car between 2,000-2,500 rpm's!!!). At this point I am concerned and contacted a local buddy that has a scan tool. This is what we found....

I assume neither of these are any issue, they also stated pending....
PO430- Catalyst Efficiency Bank 2
PO420 - Catalyst Efficiency Bank 1

THIS ONE HAS ME CONCERNED
PO369 - Camshaft Positioning Sensor, Intermittent Bank 1 Sensor 2

Any information would be appreciated! Thank you, Jeremy

[01sapphirebob]

Did you install the MOPAR PCM for the car with the other mode you mentioned? GEN IV's were pretty sensitive to any modding unless you did the PCM.

[Stealth78]

No I did not. I was advised that the specific mods I was doing would not trigger any codes, although I do not know that as fact. Also two weeks ago when it happened it was 100% stock.

[Steve-Indy]

Is car 2008? If yes, was cam sensor replaced under RRT?

Battery voltage and age?

[Steve M]

Unfortunately, you were misinformed...those mods can and will throw codes (that's where your cat efficiency codes are coming from) with the stock PCM, although they should NOT be throwing the car into limp mode. There are two kinds of limp mode - there's the spitting and sputtering, can't drive the car anywhere type, and then there's the kind where you lose power and can't go over 2,000 RPMs (the car is actually closing one of the throttle bodies and leaving it closed when it does this). Sounds like you had type #2 - from personal experience, I've had that happen while power shifting 3-4...the check engine light started flashing, and it cut power. Turned the car off then back on, and everything was back to normal. It set a misfire code for that one, which I cleared later.

Of the codes you found, the cam position sensor is probably the most likely cause for trouble here. It might need to be swapped...if I remember correctly, there have been others that have had this happen, but I can't seem to find the info right now...

[Stealth78]

Is car 2008? If yes, was cam sensor replaced under RRT?

Battery voltage and age?

Car is indeed a 2008. What is RRT? Battery is perfect as well as voltage.

[Stealth78]

Unfortunately, you were misinformed...those mods can and will throw codes (that's where your cat efficiency codes are coming from) with the stock PCM, although they should NOT be throwing the car into limp mode. There are two kinds of limp mode - there's the spitting and sputtering, can't drive the car anywhere type, and then there's the kind where you lose power and can't go over 2,000 RPMs (the car is actually closing one of the throttle bodies and leaving it closed when it does this). Sounds like you had type #2 - from personal experience, I've had that happen while power shifting 3-4...the check engine light started flashing, and it cut power. Turned the car off then back on, and everything was back to normal. It set a misfire code for that one, which I cleared later.

Of the codes you found, the cam position sensor is probably the most likely cause for trouble here. It might need to be swapped...if I remember correctly, there have been others that have had this happen, but I can't seem to find the info right now...

Thank you! Do you happen to know what a new sensor cost? Assuming I can just get it at the dealer? I bought this car last year with only 1,846 miles on it, it turned 3,500 today. So as far as I know nothing has been replaced and is all original.

[Steve M]

I've never had to replace mine, but a quick Google search netted me part number 5149054AC...looks like it's around $15 bucks or so. Not sure if that's the right part number, but should get you heading in the right direction.

[Steve-Indy]

RRT...Rapid Response Transmission...Dealers received the cam sensor RRT on early 08 Vipers such as Venom Red, SSG, ? others which meant that the original can sensors needed to be changed BEFORE said vehicle could be sold. Some failed to heed this, code popped up right away. The sensor is easily accessed at the rear of he motor on the passenger side...might be worth separating connector, then reconnecting it to see if situation improves. CAUTION: the 2008 Service Manual on CD is WRONG on cam sensor location...it leads one to remove intake, leads one to knock sensor needlessly.

[IndyRon]

Get the Venom PCM and I bet you your problems go away.

[Stealth78]

Thank you so much fellas! You guys ROCK!!! :dude3:

[Steve-Indy]

By the way, if you end up changing cam sensor, it is less than $20...and, at least in the recent past, your dealer may stock it as I THINK it may fit minivans.

[Rmj]

My car (2008) would go into limp during a full throttle pull at upper rpm even with a mopar pcm...cam sensor fixed it.

[Stealth78]

Cam sensor ordered, should have it by Wednesday. Thanks again guys!

[Stealth78]

Have the sensor. Steve-Indy mentioned earlier that the 2008 manual leads you to the wrong location. Also indicated that it is easily accessible at the passenger side rear of the engine. Is this easily accessible from under the hood or do I need to get under the car?

[Steve-Indy]

Send an email to me and I will send the info from the 09 Manual if you like. Zvipers@aol.com

[Rmj]

It is under the intake manifold toward the rear; I have a gen v intake on my car and had to remove it to get to the sensor. Not sure if the gen 4 manifold has to come off to get to it. Either way, access from the top, rear of the intake manifold.

[RedTanRT/10]

Have the sensor. Steve-Indy mentioned earlier that the 2008 manual leads you to the wrong location. Also indicated that it is easily accessible at the passenger side rear of the engine. Is this easily accessible from under the hood or do I need to get under the car?

Stealth, hope this picture helps, you need to get under your car, Dan Cragin doing roadside service at the track!! Buy a spare cam sensor. Some of the '08's had issues like your's, many good threads on the vca site. My issue was backfiring around 5k, as well as going into limp mode. After a couple of cam sensors, then a crank sensor, they ultimately swap my wiring harness.

Venom ECU won't eliminate limp mode. If you bang the rev limiter a few times it can go into limp mode. Dan told me even with the upgraded ECU it is still sensitive. Good luck, and again, look at the old threads in the vca, lots of info there. Mike

http://gallery.viperclub.org/data/500/medium/Dan_Cragin_Willow.jpg

[Stealth78]

Eeehhhhrrrr..... These last two posts could not possibly contradict one another any more??? Just to be 100% clear here, we are talking about the camshaft positioning sensor. At this point I'm going to assume I need to go under the car.

[Stealth78]

Stealth, hope this picture helps, you need to get under your car, Dan Cragin doing roadside service at the track!! Buy a spare cam sensor. Some of the '08's had issues like your's, many good threads on the vca site. My issue was backfiring around 5k, as well as going into limp mode. After a couple of cam sensors, then a crank sensor, they ultimately swap my wiring harness.

Venom ECU won't eliminate limp mode. If you bang the rev limiter a few times it can go into limp mode. Dan told me even with the upgraded ECU it is still sensitive. Good luck, and again, look at the old threads in the vca, lots of info there. Mike

http://gallery.viperclub.org/data/500/medium/Dan_Cragin_Willow.jpg

So you are saying I may continue to have this problem? Why did you have to swap out your entire harness? Does occasionally bumping the Rev limiter somehow make these sensors go bad? Between two SRT10 Rams (2004 & 2006) and my 06 coupe I have never had an issue over the past 7 years and I have to admit I've tapped that rev limiter more times than I can count. Is this going to be a chronic problem on my GenIV?

[RedTanRT/10]

Stealth, back when they were newer, a number of G4'a seemed to go through cam sensors, again a wealth of info on that subject on the voa. My car was one of a handful that they couldn't figure out so they replaced the harness

Hitting the rev limiter won't necessarily put you in limp mode every time, but it can

[Rmj]

https://driveviper.com/forums/threads/14918-Gen4-Cam-Sensor-Location
Read this all the way through. I didn't have skinny enough hands under the gen v intake;)
My car would go into limp every time I hit the rev limiter.
Cam sensor (under intake manifold) cured it completely. Not sure what's under the car (crank sensor or wiring maybe).
My cam sensor was under the intake manifold, and I HAD to remove the intake to replace it...

[Stealth78]

Send an email to me and I will send the info from the 09 Manual if you like. Zvipers@aol.com

Email sent

[Stealth78]

Okay... mild frustration setting in! With all due respect who out of the people that are advising me have done this themselves? I do not see any other way outside of the way Rmj is advising. Unless there was a relocation done for the 09 & 10 models it is indeed located under the intake manifold. The picture of Dan Cragin above has me scratching my head, unless Dan has fingers 15 inches long I do not see how this can be accomplished from under the car as I just had my car up on a lift this morning. The camshaft positioning sensor on my 08 is indeed under the rear of the intake manifold. Which brings me to my next question... If I need to pull the intake will I need any new gaskets before I start taking things apart???

[Steve M]

The intake is easy to remove...just remove the bolts, unhook the vacuum lines, disconnect the MAP sensor and throttle bodies, and pull it out. The seals are all reusable.

[Steve-Indy]

Get any email?

[RedTanRT/10]

Stealth, sorry for any confusion with my picture post. That picture is 7 years old, and so is my memory, he may have also been swapping the crank sensor.

I see someone offered to send you the shop manual, from a better memory, I thought the cam sensor was almost a quick plug and play? Take a look at the shop manual and good luck!!

[Stealth78]

The intake is easy to remove...just remove the bolts, unhook the vacuum lines, disconnect the MAP sensor and throttle bodies, and pull it out. The seals are all reusable.

Thank you!

- - - Updated - - -


Get any email?

Yes Sir! Did you not receive my response(s)? THANK YOU!!!

[Stealth78]

Stealth, sorry for any confusion with my picture post. That picture is 7 years old, and so is my memory, he may have also been swapping the crank sensor.

I see someone offered to send you the shop manual, from a better memory, I thought the cam sensor was almost a quick plug and play? Take a look at the shop manual and good luck!!

No worries my friend! This is my first GenIV so this is all new ground for me. For future the camshaft positioning sensor is 100% under the rear of the intake manifold! Kind of wishing I had the hand size of the guy from the old Burger King commercials right about now. Lol!

[Stealth78]

Final post!!! Success! I was able to get it done this afternoon. I did NOT have to remove my intake manifold. I removed the Wiper cowl and had just enough room to get my hand between the back of the intake manifold and the firewall. This is definitely a job that is done from the top with no jacks or lifts needed. Thank you all for your help, especially Steve-Indy!

[RedTanRT/10]

Great news!!!

[Steve-Indy]

Good going, Stealth78 !!!

[Rmj]

Good job! Did it fix the problem? I think the gen v intake is a tiny bit larger (or my hands are). Just looking at pics, it appears the gen v is much closer to the cowl than stock on a gen 4 (if that's possible). With the cowl off, I could not reach the cam sensor. Anyway, glad it worked out for you.
Richard

[viperBase1]

..from personal experience, I've had that happen while power shifting 3-4...the check engine light started flashing, and it cut power. Turned the car off then back on, and everything was back to normal. It set a misfire code for that one, which I cleared later.
I had this EXACT experience this morning. (Charging the phone OBDII now to check/clear the codes.)

But I had been following this thread, so I didn't freak.
Was power shifting 3-4 on a very bumpy bit of highway (just after the on ramp).. seemed like there was a ton of stuff happening in that moment.
Took me all of 3 seconds to conclude it was "Limp Mode".

So thanks for the thread Stealth, saved me some serious anxiety.

[Steve M]

I had this EXACT experience this morning. (Charging the phone OBDII now to check/clear the codes.)

But I had been following this thread, so I didn't freak.
Was power shifting 3-4 on a very bumpy bit of highway (just after the on ramp).. seemed like there was a ton of stuff happening in that moment.
Took me all of 3 seconds to conclude it was "Limp Mode".

So thanks for the thread Stealth, saved me some serious anxiety.

If I'm not mistaken, you have the Mopar PCM, but not the latest Arrow flash in your beast...if that's the case, the Arrow flash would likely fix the problem. From Arrow's website:

- Improved throttle response and feel and a more aggressive pedal map
- Misfire monitor disabled which will allow use of other engine and driveline changes without false misfire detection
- Airflow rationality monitor disabled which will allow changes to air cleaners, ducts and filters, hood scoop and other inlet side modifications without limp-out
- Temperature rationality disabled to prevent MIL’s due to changes to the cooling system, oil cooler or oiling system
- Leak detection system disabled to allow use of fuel cells without LDP MIL’s
- Rev limit increased to 6600 rpm for track use
- More aggressive exhaust note on deceleration (i.e. popping)

The second bullet (or lack thereof) is likely your issue...I went in with HPTuners on mine and disabled misfire detection, and haven't had it come back since. I need to do some more "testing" to verify, but if you are throwing a misfire code, that's the most likely cause.

[viperBase1]

If I'm not mistaken, you have the Mopar PCM, but not the latest Arrow flash in your beast...if that's the case, the Arrow flash would likely fix the problem. From Arrow's website:

- Improved throttle response and feel and a more aggressive pedal map
- Misfire monitor disabled which will allow use of other engine and driveline changes without false misfire detection
- Airflow rationality monitor disabled which will allow changes to air cleaners, ducts and filters, hood scoop and other inlet side modifications without limp-out
- Temperature rationality disabled to prevent MIL’s due to changes to the cooling system, oil cooler or oiling system
- Leak detection system disabled to allow use of fuel cells without LDP MIL’s
- Rev limit increased to 6600 rpm for track use
- More aggressive exhaust note on deceleration (i.e. popping)

The second bullet (or lack thereof) is likely your issue...I went in with HPTuners on mine and disabled misfire detection, and haven't had it come back since. I need to do some more "testing" to verify, but if you are throwing a misfire code, that's the most likely cause.
You are correct Steve!

She had the Mopar PCM on first arrival. Had to swap in the stock PCM for CA Smog and have left it in place.
So again, huge thanks for the info.. and all of it is need to know. But there are other things about the stock PCM I like (for now).
Guess it's proof I'm pushing on the pedal a bit more :devilish:

Also, rolled her out yesterday afternoon (after a complete cool down) and the code cleared on it's own and the engine light went out.
She's a good girl.

[Steve M]

You are correct Steve!

She had the Mopar PCM on first arrival. Had to swap in the stock PCM for CA Smog and have left it in place.
So again, huge thanks for the info.. and all of it is need to know. But there are other things about the stock PCM I like (for now).
Guess it's proof I'm pushing on the pedal a bit more :devilish:

Also, rolled her out yesterday afternoon (after a complete cool down) and the code cleared on it's own and the engine light went out.
She's a good girl.

Forgot that you had swapped back in the stock PCM...when I ran into a misfire issue on mine, it did not clear on its own. Did you get an OBD-II reader on it to see if anything was stored?

[viperBase1]

Did you get an OBD-II reader on it to see if anything was stored?

P0369 - Camshaft Position Sensor "B". Circuit Intermittent (Bank 1)

Sound familiar?

[Stealth78]

P0369 - Camshaft Position Sensor "B". Circuit Intermittent (Bank 1)

Sound familiar?

Go back to my very first post in this thread. This is the exact same code I had. You are more than likely going to have to replace the camshaft positioning sensor. I did NOT have to remove the intake manifold but someone else mentioned that it may be a tighter fit to get your hand in there with the GenV intake, which I do not have yet. I would try and remove the wiper cowl like I did and see if you can get your hand in there, the sensor is held in by a single bolt into the block under the back of the intake manifold. I paid $27 for the sensor (that may have covered the shipping too, I'll have to look back). Good Luck!

[Stealth78]

Good job! Did it fix the problem? I think the gen v intake is a tiny bit larger (or my hands are). Just looking at pics, it appears the gen v is much closer to the cowl than stock on a gen 4 (if that's possible). With the cowl off, I could not reach the cam sensor. Anyway, glad it worked out for you.
Richard

Yes it did fix the problem! Do you have any pictures of how tight it is at the firewall with the GenV intake and wiper cowl removed?

[Rmj]

No, I didn't take any pics, but looking at every pic I've seen of a gen 4 with a gen v intake, versus pics of a stock intake, the gen v appears to be closer to the firewall. Not by much, but it doesn't take much to make it impossible. I really don't have very big hands, and I physically could not touch it with the cowl removed. I probably wouldn't have bothered if I had known for sure that the arrow flash would cure the symptom anyway:). For what it's worth, my codes never cleared themselves either, but I have a scangauge mounted above the mirror...I always cleared the codes myself before putting the car away. Good info above from Steve. Steve I see from your sig that you have hi flow cats. Is that with stock exhaust otherwise? Curious as to how much louder it is than stock and if it made a noticeable difference in power?

[Rmj]

http://s29.photobucket.com/user/rpinieck/media/Gen%205%20Intake/EB24B3BD-E8F5-4355-AC7D-5AE9464F108E_zps8k4o942o.jpg.html

http://s29.photobucket.com/user/rpinieck/media/Gen%205%20Intake/55C31A70-4F0E-41C8-BD97-BCFF0FC4710A_zpsmdek2dhu.jpg.html

Images courtesy of IndyRon as posted in his intake how-to.
I stand corrected; it appears that the gen v may have MORE room than stock. It's been a long time since I installed mine, but I remember not being able to with the cowl removed...maybe my hands just were too big...

[Stealth78]

http://s29.photobucket.com/user/rpinieck/media/Gen%205%20Intake/EB24B3BD-E8F5-4355-AC7D-5AE9464F108E_zps8k4o942o.jpg.html

http://s29.photobucket.com/user/rpinieck/media/Gen%205%20Intake/55C31A70-4F0E-41C8-BD97-BCFF0FC4710A_zpsmdek2dhu.jpg.html

Images courtesy of IndyRon as posted in his intake how-to.
I stand corrected; it appears that the gen v may have MORE room than stock. It's been a long time since I installed mine, but I remember not being able to with the cowl removed...maybe my hands just were too big...

Hmmmmm.... Huge hands eh...? Bet you have a size 14 shoe too? No worries bud, Meatloaf once said 2 out of 3 ain't bad! LMAO!!! In all seriousness I am not a large guy but I definitely don't have petite hands. I'm not saying it was easy but clearly it wasn't an impossible task either. To be honest if there is additional clearance with the GenV intake Rob Gronkowski could fit his hands in there. Those pictures definitely make it look more accessible with the GenV intake unless it's because there is less clearance height wise under the intake.

[Rmj]

Ahhhh!! I believe you're right. I remember being able to get the bolt out, I don't think the intake was high enough to get the sensor out. That's my story and I'm stickin' to it:)