limp mode/3rd brake/dtc codes

SeanH

Member
im currently in the process of tuning the car and during logging ill get one good pull (pulls like a rocket 23 psi) then only get maybe 5 psi and under powered. these are my current codes. my brake light is on. cruise control does not work. parking brake is grounded. i have a 25w 100ohm resistor wired in for the CMHSL which shows 8.5 volts without brake applied. all lights work. would any of the codes below put in limp ?

B3903 (current, old, history) stop lamp relay circuit BCM


can i disable these in hptuners?

U2113 (current, history) lost communication sensing diagnostic module SDM BCM aig bag?
U2125 (current, history) lost communication com con sys
U2172 (current, history) raidio
P0532 A/C Refrigererant pressure sensor A circuit low (pending,cur,old,history)
U0121 lost communication abs module
U2108 (current,old,history) CAN bus Erros ABS

looking for input/direction

thank you! :)
 

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Gtstorey

Goblin Guru
And the only one of the codes you posted that can be turned off by HPT is the P code. But that is the only one of those to set off the check engine light. But that P code shouldn't limit boost, at least I don't think it will.
 

Gtstorey

Goblin Guru
What are you running that is non stock? Map Sensor, Boost Sensor, Injectors etc? It looks you are running the GM stage 1 Map sensor and the stock/original boost sensor? With Stock boost sensor you will max it out and run more boost than you think.

I'm not sure that disabling P0234 in HPT truly disables it. I think I was still getting it when I had my boost turned up when checked with something besides HPT. Try turning it back on and see if it sets when this problem occurs.
 

Gtstorey

Goblin Guru
Both Map Sensors? If so, you need to match the boost sensor under airflow/supercharger to the map sensor settings under the airflow/general. You might want to confirm the part numbers first.
 

SeanH

Member
Yes both map sensors, specifically the package zzp offers. I’ll have to check both those settings after work! Would be awesome if that’s it ! Thank you for everything
 

SeanH

Member
so i updated the map settings under airflow/supercharger and not i have no boost? and basically no power
 

SeanH

Member
so i went back a couple revisions on the tune. to essentially go back to stock for flow rate injector const. and the maf frequency changes i had made to start over with the maps being set correctly. i had one good pull towards the end, but hit ~24 psi, and then limp mode after that. do i not have the over boost parameters set correctly ?
 

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Gtstorey

Goblin Guru
Did you confirm MAP part numbers? Now that the car knows how much boost it’s really making you may need to increase the boost that is being called for. It may have been making more boost than the ECM called for.

I’ll try and review the tin/log this evening.

But I think I confirm that P0234 will still set even though it doesn’t turn on the check engine light. Mine had always set when I was passing multiple cars and would not boost until the code was cleared, I lost boost while passing several cars in a row today, but no check engine light because P0234 is set to disable. This time boost returned by just turning the car off and restarting. So I think it still recognizes the P0234 condition but doesn’t store it like it does with the code enabled. I looked into this previously and didn’t figure out what changes to make to eliminate the problem. I haven’t spent a lot of time on since it only happens about 1 out of 15 rides or so,
 

Gtstorey

Goblin Guru
Where did you get your base file? There are several things that seemed to be change from a stock tune that I wouldn't expect to be changed. I don't see any reason that the various base injector data has been changed. Few tables that have the axis changed that I've never seen changed before.

I'm also not sure where you got your channel list for the log. Several things missing and a lot of things that I'm not sure why you would be logging.

Does the current version of HPT scanner no longer include DTC's in the log details? My older version I normally use has the DTCs set showing in the details but the newer version at least doesn't have a line labeled for it. Do you know if you have any current codes set?

You might consider starting over with the tune posted here;
LNF Starter Flash (hptuners.com)

I'll post my channel list when I get back on my other laptop that has my most current list.
 

Gtstorey

Goblin Guru
That cross references to the GM Part number for the GM upgrade kit so the linear offset should be good.
That C code is a brake position sensor code That will self clear once the setting condition is gone. So it might have been active while driving. But the service manual doesn’t indicate that it will reduce powe. It won’t start while it’s active though.

is the p0234 still active? Your throttle position was showing 0 on the last log. I don’t remember mine doing that when logging while I had that code.

Have you compared your initial read to a stock file from HPT repository?
 

SeanH

Member
i have p0234 disabled. the last log i had one good pull or a pull where i had all power (assuming not in limp). then everything following felt like i lost all power and could floor it, maybe hit 5 psi.

just compared my stock tune i saved to the hptuners one. decent number of differences, at least from what i understand when looking at them compared.
 

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Gtstorey

Goblin Guru
As I previously stated I don’t think the HPT gets rid if it completely. Turn it on and see if it pops. It sounds like what mine did today.
I think you need to start all over with a clean base tune. Either a stock tune or the one I linked. I’ll see if anything stands out between the two files.

Are you using any filters while adjusting the maf?
 

Gtstorey

Goblin Guru
You need to filter out deceleration fuel cut off unless you can figure out how to drive without it going into that mode. You need to monitor misfires (it’s normal for the LNF to have a few) and leave out any data when that happens. Sudden acceleration and deceleration needs to be filtered, although I’m not currently using it. It’s on my list to figure out how rare of change filters work.
Right now I break maf tuning into two parts. One is low speed, parking lot, neighborhood driving, the other is normal road driving. This way I get plenty of hits in the low speed areas. Then I can filter out low throttle settings that are when the dfco is active when open road driving.
 
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