Limp Mode after dead battery

[v10CodeMonkey]

Needing some help diagnosing a limp mode issue on my '08. About a month ago, group of us Vipers here drove the cars to an oval track (about a 45 minute drive) for a few laps. When I got there I went inside for a 20 minute driver's meeting and came out to a completely dead battery. Had to get it jumped from both a jump pack and another car to get it going. Check engine light was on at this point. By this time I had missed my track time, so headed for home but had to stop along the way at a gas station so one of the other Vipers could fill up. I left mine running bc I didn't know if I could get it started again. Idled for maybe 5-6 minutes. Got in to go and almost immediately went into limp mode. Normally I would shut it off and let it sit for a bit and then restart to see if limp mode clears, but bc of the weak battery I decided to just limp it home. Got home, bought and installed a new battery and it fired right up, no more limp mode. I did notice that the positive terminal of the battery cable was very corroded and eaten away. I wanted to see if the new battery solved the issue so I just used the corroded terminal again, with the plan to replace in the future.

Over the course of the next month I drove the car 4 or 5 times and noticed some (very) slight surging in the lower RPMs when accelerating. Chalked it up to the PCM relearning/adapting after having driven in limp mode for several miles. It smoothed out a little as I drove it.

This past week, got the car out again and drove for about 20 minutes and it ran great, then sat in parking lot for 10 minutes idling before heading for home and again, it went into limp mode. Limped it home, let it sit for a while then fired it up and limp mode gone. Next day I replaced the corroded battery terminal and have run the car a couple times since then without issue. Today, I drove about 10 minutes, then stopped and let it idle in driveway about 6 minutes. Started to pull it back into garage and it went into limp mode again. So letting it idle for some time seems to be a trigger.

Below are the codes it threw this last time, I know many are due to the limp mode itself. Any ideas why it going into limp mode? This all started after the dead battery, never had issues before that. Seems to pop up after idling for a while.

My car mods - Arrow controller (installed in 2016), ACR-X Headers (installed 2014), Gen V intake manifold (installed this past spring).

Screenshot_20181020-122947_Torque.jpg

[viperBase1]

Hey CodeMonkey.. Code Tester here. Sounds like our cars are VERY similar.

I've gone into Limp Mode twice.
#1
After getting on it (the throttle) on a ruff patch of road which caused the entire car to vibrate SEVERELY.
But it hasn't happened since. I blamed it on the severe vibration.

Any odd-consistent vibrations going on?


#2
Do you have an Oil Catch Can? If so, drain that puppy!

Sounds like you got the dead battery issue solved. I replaced my battery terminals too (w/new battery). Those low profile OEM terminals so suuuuuucccckkkk.



Here is the text from the shop manual on those error codes . (except for 2021.. doesn't have that one)

P2104 ELECTRONIC THROTTLE CONTROL SYSTEM - FORCED IDLE
P2106 ELECTRONIC THROTTLE CONTROL SYSTEM - FORCED LIMITED POWER
P2110 ELECTRONIC THROTTLE CONTROL - FORCED LIMITED RPM - BANK 1 <= we have a Bank!
P2101 ELECTRONIC THROTTLE CONTROL MOTOR PERFORMANCE - BANK 1
P2106 ELECTRONIC THROTTLE CONTROL SYSTEM - FORCED LIMITED POWER
P2110 ELECTRONIC THROTTLE CONTROL - FORCED LIMITED RPM - BANK 1


Based on the codes, check/clean/reseat all connectors for both Throttle Bodies.
I'd pull the intake tubes and get a look inside, check for gunk.. clean as needed (NEVER put your fingers in there, they can bite!)

From the manual:
WIRING AND CONNECTOR INSPECTION
1. Turn the ignition off.
2. Verify that the harness connector is properly connected to the throttle body.
3. Disconnect the throttle body connector.
4. Inspect the wiring and terminals for any condition that would result in a poor connection.
5. Look for any chafed, pierced, pinched, or partially broken wires.
6. Look for broken, bent, pushed out or corroded terminals.


I'd also perform a complete PCM reboot and check/clean/reseat those connectors too.
The reference to "Bank1" is on the PCM itself (ELECTRONIC THROTTLE CONTROL MOTOR CIRCUIT). I think it's the Orange one.


If that doesn't resolve the problem, then roll back to the stock PCM and see if Limp Mode goes away.

Good luck and keep up posted.

[v10CodeMonkey]

Thanks for tips ViperBase. I just now got around to looking around things and am posting pics of the TB. They are slightly open, is that normal? I have a picture of them from 5 years ago and they appear to be slightly open then too, but the pic is poor quality so it's hard to tell.

20181027_160916.jpg

[Steve M]

Thanks for tips ViperBase. I just now got around to looking around things and am posting pics of the TB. They are slightly open, is that normal? I have a picture of them from 5 years ago and they appear to be slightly open then too, but the pic is poor quality so it's hard to tell.

20181027_160916.jpg

Yes, that's normal - it's how the PCM handles idle air flow on a drive by wire throttle body car. They are always cracked at least some to allow enough air into the intake manifold to maintain the desired idle speed.

[viperBase1]

Your TB's look a little gunky.

That oily trail down the center of your TB suggests you do NOT have an Oil Catch can.
oilTB.PNG

If so, you should get one.
All that gunk will accumulate in the can and keep the TB's (and everything behind 'em) clean[er].


I have an ACR-X Oil Catch Can I can flow you dirt cheap if interested.
It's an OPEN breather, but works great.