HKE LSX 427 with D1SC is in!!! but WTFO?

[DJ_BigC]

Alright, since your vehicle is going into limp mode, or "reduced engine power" there should be codes stored into your ECM under DTC's when this random hick up happens. Now I with a GM MDI I never had an issue with pulling any codes from any modules, even when the problem was very random and tricky.

Now from my understanding their aren't very many reasons why "reduced engine power" message comes on, but I could be wrong. If you had a list of stored codes, that are current or in history, I would be able to help you out more. But since I didn't see any codes listed in this entire thread ill go out on a limb here and start with the obvious ones I've seen many times.

DTC P0120: Throttle Position Sensor 1 Circuit
DTC P0122: Throttle Position Sensor 1 Circuit Low Voltage
DTC P0123: Throttle Position Sensor 1 Circuit High Voltage
DTC P0220: Throttle Position Sensor 2 Circuit
DTC P0222: Throttle Position Sensor 2 Circuit Low Voltage
DTC P0223: Throttle Position Sensor 2 Circuit High Voltage
DTC P2135: Throttle Position Sensor 1-2 Correlation

All of these codes are throttle body sensor/wiring related. All of these codes can give you a reduced engine power message, the most common seen is the P2135, and the fix for that code is a new throttle body sensor assembly with a idle relearn and throttle body cleaning.

DTC P2120: Accelerator Pedal Position (APP) Sensor 1 Circuit
DTC P2122: Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage
DTC P2123: Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage
DTC P2125: Accelerator Pedal Position (APP) Sensor 2 Circuit
DTC P2127: Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage
DTC P2128: Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage
DTC P2138: Accelerator Pedal Position (APP) Sensor 1-2 Correlation

These are all accelerator pedal sensor/wirring codes that can/will give you a reduced engine power message. The most common is the P2138. Now with this codes if any water got around or inside the I/P fuse block, mostly on new model pickups (07-current, not sure if this applies to the Camaro) it causes a short between terminals and excessive resistance at that connector causing a P2138 to set. In that case the gas pedal is not the problem its a wiring repair that needs to performed and/or a water leaks also needs to be repaired, this problem is usually common on vehicle with sunroofs or windshields that have been improperly replaced. Most often, if all connectors and wiring tests OK, I can say that the gas pedal assembly is most commonly replaced. Once replaced the technician needs to inspect and make sure that the data being displayed on the scan tool corresponds with the pedal travel.

Last but not least I have also seen a P2135 code set with or without P0651. When I had diagnosed this condition I found pinched wirring on the right inner fender about 6" from the ECM, I repaired the wires as necessary and rerouted and it fixed the problem, I also found pinched wires at connector X102 that was causing them to short together. This is a big connector (40 Cavity) it is located to the right of the car around the under hood fuse block.

Some people may say that their might be more reasons why a reduced engine power message may come on and they might be right but these are the most common that I've seen and without a code posted, I can't start writing every code ECM down.

Now the post above has a great point, seeing as how a lot of people have been inside that ECM, a terminal tension test on every pin is a must. If i remember correctly, the ECM connector female terminals are .64, they are very small and if someone was in there with the wrong test probe, you'll be changing some terminals.

A drag test on every pin should be performed at the ECM, along with the throttle body and the accelerator pedal and all of their corresponding connectors in order to diagnose and test the the wiring properly, all terminals, male and female should be checked for corrosion, terminal fretting corrosion, poor terminal tension or damage. From connector to connector for either sensors (throttle and accelerator pedal) all the way to the ECM they should not see more then 1 ohm resistance, they will most commonly see anything from 0.5-0.9 ohms per wire. If anything is higher then 5 ohms (which is still acceptable but high) they should test for short to grounds/voltage etc.. and start taring the harness apart and looking for wiring that has rubbed through or rubbed together and or broken/breaking wires. If all checked good, I would replaced the ECM.

If you do decide to get it replaced and bring it to the dealer for them to program it, the tech will need to do an crankshaft learn which requires him to start the car, if you have the dealer do it, make SURE to specify that you only want it loaded into the ECM, with no car starting what so ever to prevent damage.

The only thing I read that I have to disagree with is, if there is any kind of dielectric grease in any connector within those circuits, remove it. There should NEVER be any dielectric grease in ANY module connector unless the replacement procedure specifies to put some in it, I have seen some modules do some really funny things with dielectric grease in its connectors. GM has released bulletins and PI's about this in the passed about tech's excessively using this stuff causing intermittent problems, I'm not saying its no good, im just letting you know on some useful information.

If you can get your hands on a list of DTC's (codes), let me know ASAP and I will pull up schematic and diagrams and try and help you/them diagnose it. If you needs any terminal/test probe information let me know I can give you part numbers and help you find/replace and locate terminals to get that problem fixed for you. Who knows it might also be a custom tune issue, doubt it, but its possible and out of my league lol!!

[solobaric]

Wow! Subscribing for the solution! Good luck!

[BullF-16]

Originally Posted by DJ_BigC

Alright, since your vehicle is going into limp mode, or "reduced engine power" there should be codes stored into your ECM under DTC's when this random hick up happens. Now I with a GM MDI I never had an issue with pulling any codes from any modules, even when the problem was very random and tricky.

Now from my understanding their aren't very many reasons why "reduced engine power" message comes on, but I could be wrong. If you had a list of stored codes, that are current or in history, I would be able to help you out more. But since I didn't see any codes listed in this entire thread ill go out on a limb here and start with the obvious ones I've seen many times.

DTC P0120: Throttle Position Sensor 1 Circuit
DTC P0122: Throttle Position Sensor 1 Circuit Low Voltage
DTC P0123: Throttle Position Sensor 1 Circuit High Voltage
DTC P0220: Throttle Position Sensor 2 Circuit
DTC P0222: Throttle Position Sensor 2 Circuit Low Voltage
DTC P0223: Throttle Position Sensor 2 Circuit High Voltage
DTC P2135: Throttle Position Sensor 1-2 Correlation

All of these codes are throttle body sensor/wiring related. All of these codes can give you a reduced engine power message, the most common seen is the P2135, and the fix for that code is a new throttle body sensor assembly with a idle relearn and throttle body cleaning.

DTC P2120: Accelerator Pedal Position (APP) Sensor 1 Circuit
DTC P2122: Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage
DTC P2123: Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage
DTC P2125: Accelerator Pedal Position (APP) Sensor 2 Circuit
DTC P2127: Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage
DTC P2128: Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage
DTC P2138: Accelerator Pedal Position (APP) Sensor 1-2 Correlation

These are all accelerator pedal sensor/wirring codes that can/will give you a reduced engine power message. The most common is the P2138. Now with this codes if any water got around or inside the I/P fuse block, mostly on new model pickups (07-current, not sure if this applies to the Camaro) it causes a short between terminals and excessive resistance at that connector causing a P2138 to set. In that case the gas pedal is not the problem its a wiring repair that needs to performed and/or a water leaks also needs to be repaired, this problem is usually common on vehicle with sunroofs or windshields that have been improperly replaced. Most often, if all connectors and wiring tests OK, I can say that the gas pedal assembly is most commonly replaced. Once replaced the technician needs to inspect and make sure that the data being displayed on the scan tool corresponds with the pedal travel.

Last but not least I have also seen a P2135 code set with or without P0651. When I had diagnosed this condition I found pinched wirring on the right inner fender about 6" from the ECM, I repaired the wires as necessary and rerouted and it fixed the problem, I also found pinched wires at connector X102 that was causing them to short together. This is a big connector (40 Cavity) it is located to the right of the car around the under hood fuse block.

Some people may say that their might be more reasons why a reduced engine power message may come on and they might be right but these are the most common that I've seen and without a code posted, I can't start writing every code ECM down.

Now the post above has a great point, seeing as how a lot of people have been inside that ECM, a terminal tension test on every pin is a must. If i remember correctly, the ECM connector female terminals are .64, they are very small and if someone was in there with the wrong test probe, you'll be changing some terminals.

A drag test on every pin should be performed at the ECM, along with the throttle body and the accelerator pedal and all of their corresponding connectors in order to diagnose and test the the wiring properly, all terminals, male and female should be checked for corrosion, terminal fretting corrosion, poor terminal tension or damage. From connector to connector for either sensors (throttle and accelerator pedal) all the way to the ECM they should not see more then 1 ohm resistance, they will most commonly see anything from 0.5-0.9 ohms per wire. If anything is higher then 5 ohms (which is still acceptable but high) they should test for short to grounds/voltage etc.. and start taring the harness apart and looking for wiring that has rubbed through or rubbed together and or broken/breaking wires. If all checked good, I would replaced the ECM.

If you do decide to get it replaced and bring it to the dealer for them to program it, the tech will need to do an crankshaft learn which requires him to start the car, if you have the dealer do it, make SURE to specify that you only want it loaded into the ECM, with no car starting what so ever to prevent damage.

The only thing I read that I have to disagree with is, if there is any kind of dielectric grease in any connector within those circuits, remove it. There should NEVER be any dielectric grease in ANY module connector unless the replacement procedure specifies to put some in it, I have seen some modules do some really funny things with dielectric grease in its connectors. GM has released bulletins and PI's about this in the passed about tech's excessively using this stuff causing intermittent problems, I'm not saying its no good, im just letting you know on some useful information.

If you can get your hands on a list of DTC's (codes), let me know ASAP and I will pull up schematic and diagrams and try and help you/them diagnose it. If you needs any terminal/test probe information let me know I can give you part numbers and help you find/replace and locate terminals to get that problem fixed for you. Who knows it might also be a custom tune issue, doubt it, but its possible and out of my league lol!!

I forwarded this to my shop. Thanks a ton!!!!!!!!!!!

As far as i know the only code that pops up is P0606 PCM internal comm failure. My tuner had his laptop hooked up and this is also what he was seeing. He disabled the code in the tune and the car still would go into limp mode. He reinstalled it the then it would limp and display the same p0606

I will ask my shop if any other codes were displayed on the lap top

[Matt @ FSP]

Originally Posted by BullF-16

I forwarded this to my shop. Thanks a ton!!!!!!!!!!!

As far as i know the only code that pops up is P0606 PCM internal comm failure. My tuner had his laptop hooked up and this is also what he was seeing. He disabled the code in the tune and the car still would go into limp mode. He reinstalled it the then it would limp and display the same p0606

I will ask my shop if any other codes were displayed on the lap top

No offense to anyone, but the tuner should know that the P0606 is a hard error code, disabling it to no reported error does not mean it will go away. Just like a P0068 code or (The older LS1s) P1514 (Or basically any APP or TPS codes are the same way).. You can disable the code, but the effects are still there.

The P0606 is a ECM internal fault. I've had a few issues before that I saw with a certain tuning suite and the patch for 160*+ tstat we ruined a couple of PCM's over it. It will be completely random and usually happens as soon as the client takes the vehicle! I would HIGHLY recommend you flash the computer back to stock with the GM MDI tools (NOT EFILive/HPT - If you even do a Full flash it will NOT get rid of the P0606) to see if you can knock the error out. If that does not work then I'd buy a new ECU. Remember this has to be done as a DEALER LEVEL flash. Some shops can perform the flash as also as long as they have GM Global login & a GM MDI (We have this login and tool here on-site).

I highly doubt this is a wiring issue, but of course without being in front of the car there is no way to tell this. I just think the ECU got some bad data, and needs a FACTORY Gm flash then pull the program, script or compare it and put the tune in (I would NOT flash back in the same file, I would pull the factory one and re-write the parameters to that). Then avoid doing the MAF enhanced patch.

Same thing I PM'd you a few weeks ago

[DJ_BigC]

That code can apply for the ECM or the FPCM or both, if that code sets, they should clear it, once cleared if it sets again, then their is a fault within your ECM or FPCM. Now I know you dont have a FPCM anymore, I think I read that the tuner removed that modules data from the ECM with his tune. If he didnt I would remove it, delete the FPCM data from the ECM and try it again (If they can actually do that lol, I'm not tuner by any means).

If he did this already I would purchase a new ECM from the dealer, have it flashed to stock with the MDI but make sure that car not is started at the dealer, bring it then back to your tuner and have him load up his tune with the FPCM removed and all other data loaded to get the car running properly. Then I would road test it and to my understanding the condition should no longer be present.

If it is I would start look at the accelerator pedal for a problem since most of the ECM's and FPCM's data for that code is mostly in relation with the data it receive from the accelerator pedal.

Now I know this is long shot, but is your car auto or stick. An auto trans can also set some reduced engine power codes. If you want them I can list them.

[BullF-16]

Originally Posted by DJ_BigC

That code can apply for the ECM or the FPCM or both, if that code sets, they should clear it, once cleared if it sets again, then their is a fault within your ECM or FPCM. Now I know you dont have a FPCM anymore, I think I read that the tuner removed that modules data from the ECM with his tune. If he didnt I would remove it, delete the FPCM data from the ECM and try it again (If they can actually do that lol, I'm not tuner by any means).

If he did this already I would purchase a new ECM from the dealer, have it flashed to stock with the MDI but make sure that car not is started at the dealer, bring it then back to your tuner and have him load up his tune with the FPCM removed and all other data loaded to get the car running properly. Then I would road test it and to my understanding the condition should no longer be present.

If it is I would start look at the accelerator pedal for a problem since most of the ECM's and FPCM's data for that code is mostly in relation with the data it receive from the accelerator pedal.

Now I know this is long shot, but is your car auto or stick. An auto trans can also set some reduced engine power codes. If you want them I can list them.

Its a M6. SNL says they already swapped out the ECM/PCM but i dont know the source of the base tune, from the dealer or from my shop?

I have forwarded all these recent replies to SNL. Thanks a bunch! Really!

Hopefully they are checking the accel pedal assembly and wiring to the PCM and TB very carefully.

I was thinking new ECM with factory stock tune then starting all over from scratch with SNL's local tuner using HP tuners.

Pat Guerra tuned this car and drove up from the Houston area and he uses EFI Live.

[Matt @ FSP]

Originally Posted by BullF-16

Its a M6. SNL says they already swapped out the ECM/PCM but i dont know the source of the base tune, from the dealer or from my shop?

I have forwarded all these recent replies to SNL. Thanks a bunch! Really!

Hopefully they are checking the accel pedal assembly and wiring to the PCM and TB very carefully.

I was thinking new ECM with factory stock tune then starting all over from scratch with SNL's local tuner using HP tuners.

Pat Guerra tuned this car and drove up from the Houston area and he uses EFI Live.

Pat is one of the best tuner's in the country, so I would not just throw his tune out the window IMO...

As per the ECU, it must be done with GM MDI tooling with dealer level access. This is NOT like the old ECU's where you could just flash a program and throw it in a donor car. These ECU's need to be sync'd when they are installed, once again through GM Global Connect using GM MDI tools. Process is Remove & Replace ECU; Flash Factory Base Engine Control Module Tune In; IMMO Learn for ECM and BCM (Immobilizer Learn for ECU and BCM, there are four options this is the longest of the four); Clutch Pedal Learn (If Manual); Idle Learn. It's a length process actually because the IMMO process stops at one point for 10 minutes while modules all reset.

[BullF-16]

Originally Posted by Matt @ FSP

Pat is one of the best tuner's in the country, so I would not just throw his tune out the window IMO...

As per the ECU, it must be done with GM MDI tooling with dealer level access. This is NOT like the old ECU's where you could just flash a program and throw it in a donor car. These ECU's need to be sync'd when they are installed, once again through GM Global Connect using GM MDI tools. Process is Remove & Replace ECU; Flash Factory Base Engine Control Module Tune In; IMMO Learn for ECM and BCM (Immobilizer Learn for ECU and BCM, there are four options this is the longest of the four); Clutch Pedal Learn (If Manual); Idle Learn. It's a length process actually because the IMMO process stops at one point for 10 minutes while modules all reset.

Thanks Matt, i forwarded this to my shop

Here is a synopsis of what has been done since this started doing this on the street tune with Pat in the drivers seat


-Aeromotive pump and speed controller and tach adapter removed
-Squash performance dual 400LPH kit installed
-Squash has looked at the tune and i believe made some changes and sent it back to SNL
-SNL is checking every wire that had to do with anything on this install
-A new ECM from GM was installed and flashed by a GM tech (dont know if MDI was used)
-No codes having anything to do with TB or accelerator pedal....just P0606 as far as I know

-right now the car is being put back together (after checking wiring etc) and will have the modified tune from Squash installed

We'll see what happens, i would say a prayer but there are more important things to pray for these days!!!

But i do have my damn fingers crossed.

Oh, i think i am starting to piss off my shop!

[BullF-16]

Originally Posted by Matt @ FSP

Pat is one of the best tuner's in the country, so I would not just throw his tune out the window IMO...

Yes, lots of research went into this decision. I even had him drive the 6 hrs up to Ft Worth for this tune.

I also had plans to drive down to Victoria to let him plug in and check everything out since so much crap has been done to the ECM/PCM and flashing base tunes, reloading Pat's tune etc!

Its funny cause i have read comments about the Aeromotive pump etc being used as $700 paperweights.....well it turns out all the Aeromotive stuff was working as advertised. I will keep it as a back up

What i have currently is a 4000LB almost $90,000 paperweight

[BullF-16]

Well, got a little good news this morning from my shop.

They had Squash scrub the tune (thanks Andy) they made some changes. Not sure if this was an issue.

also they went thru every connection and harness on the car and looked closely at the drive by wire throttle connections and wiring up to the TB.

They put it on the dyno and could not get the problem to duplicate but are not able to drive it on the street due to rain.


More to follow

[MA2010SS]

Sounds like good news. Keep us informed!

[SSBUSDRVR]

Sounds like good news. Keep us informed!

+1

[BullF-16]

Drove the car home 2 hours from Ft Worth, works and drives better than ever. Didnt beat on it till i got close to home. Got it up to 10psi boost and no issues. I will let SNL performance explain what they think it was. So much was done at once in a 2 day span i think its hard to say what the culprit was.

Huge thanks to SNL Performance aka Monster Clutch Company, Andy and Squash Performance for a full up fuel system and to Brett and Aeromotive. It turns out the fuel system from Aeromotive was never the problem, nor was the tach adapter that the Aeromotive system uses. So, i have a back up fuel system to use with my soon to be rebuilt LS3 factory motor.

Huge thanks to all those here on Camaro5 that took the time to help diagnose this major electrical gremlin running around in my system. I forwarded almost every reply in this thread to SNL.....something fixed the problem!!!!

Steve, if you have time, let these guys know more details on what you and Dustin did over the last couple weeks.

[Supercharged SS]

Originally Posted by BullF-16

Drove the car home 2 hours from Ft Worth, works and drives better than ever. Didnt beat on it till i got close to home. Got it up to 10psi boost and no issues. I will let SNL performance explain what they think it was. So much was done at once in a 2 day span i think its hard to say what the culprit was.

Huge thanks to SNL Performance aka Monster Clutch Company, Andy and Squash Performance for a full up fuel system and to Brett and Aeromotive. It turns out the fuel system from Aeromotive was never the problem, nor was the tach adapter that the Aeromotive system uses. So, i have a back up fuel system to use with my soon to be rebuilt LS3 factory motor.

Huge thanks to all those here on Camaro5 that took the time to help diagnose this major electrical gremlin running around in my system. I forwarded almost every reply in this thread to SNL.....something fixed the problem!!!!

Steve, if you have time, let these guys know more details on what you and Dustin did over the last couple weeks.

Awesome!!!! Great to see you're up and cruising along. If I had a clue I would have loved to help but I'm pretty much useless with that techy crap.

Go enjoy the car. It's been a long time and you deserve it!!! Good job not strangling anyone during this ordeal!!