TEA Brent

On vettes in the display box it says engine reduction. Does anyone know how to check to see what put the car in engine reduction. This car starts up and is instantly in it and runs like crap. Anyone seen this before. I have a tech II and it is not throwing any funny codes and I can't see anything wrong. Any ideas would be greatly appreciated.

ChrisB

engine reduction or reduced engine power? Tech II should show you the code, though I haven't use often enough to know for sure. You can use the 'vette display interface also to scroll through all the codes - I think the trick was to hold (4) and (1) at the same time (controlls on the right side of the dash). You can then cycle through the codes and use the reset button to clear them.

If you programmed the car with ls1 edit that will set this mode (ls1 edit takes over the system bus, and as such the pcm looses contact with the throttle module. When this happens low power mode is set).

TEA Brent

Sorry, it is Reduced Engine Power. I know about that problem when sending a new program, deal with it every day. But this car will not come out of reduced engine power. It starts up in it every time, with 2 seconds of it starting. The car will go into reduced engine power without setting codes. I have not seen this before.

ChrisB

And no codes are being displayed at all? That is bizzare. I would say try another PCM, but it's a bit of a PITA in a C5...

KOOL C5

iTrader: (2)

The most common code the C5 and reduced power is the 1514. If this is turned off in edit, it will still go into reduced power but not show the code.
I have had the reduced power many times over the past 6 yrs and it usually has to do with the TB and MAF not working together.
Tom

C_Williams

Have you tried to disconnect the battery and reconnect?

mikey

iTrader: (6)

Everytime you re-flash the PCM, it will loose communication with the BCM and upon first start it will go into reduced power. Clear the code and you should be ok. If there is a column lock problem the PCM will shut the car off at 1.5 MPH.

ChrisB

Using the built in code display on the C5 I always saw the code 1514 after an edit flash though (never checked through autotap/efilive as it was quicker to clear this way though).

TEA Brent

I have not tried to disconnect the battery. This car will start up in engine reduction after clearing the 1514 code. This is a brand new computer that has not seen 5 min of run time or any movement at all, just trying to get the car started and running.

TEA Brent

I did see a t-body performance code once.

mikey

iTrader: (6)

Do the VIN numbers in the BCM and PCM match? They need to match. Does the car start but shut off immediately? If so, you need to do a VATs re-learn.

Mike

KOOL C5

iTrader: (2)

Was the car runnig before the new PCM?
What about the VATs Re learn after the new PCM?

TEA Brent

What's involved in the VATS Re learn? Yes the car would run before the new pcm and yes as soon as it starts it goes to reduced engine power.

mikey

iTrader: (6)

Here ya go Brent:

1. Turn key on for minimum of 11 minutes.
2. After 11 minutes turn the key off for a minimum of 30 seconds.
3. Repeat this procedure 3 times.
4. Turn the key back on for 30 seconds then start the vehicle.

TEA Brent

I did the vats relearn and it did nothing. The vin numbers match, i'm kinda stuck. I think this will be the last car i take that someone hands me a car and huge bucket of parts. This car arrived from florida with no heads on it and a ton of parts in a box. Any other ideas?

Brains

iTrader: (7)

Damn, I feel for ya... I tried to help tune a car that was passed from shop to shop to shop, and finally to these guys who work out of their garage. This poor C5 was a VERY mild solid roller stroker, and it wouldn't even IDLE w/o the throttle open 14% ... Obviously something still screwed up there.. Getting a box of parts with some wheels on it that someone else cobbled together -- and being expected to make it run -- is NO fun at all and (nearly) never worth the time / $$$

TEA Brent

I am begining to agree completely. No more for me. I have also tried a different mass air, but haven't tried the t-body yet as this car has the oval TPIS t-body on it. So maybe changing intake and t-body will help or tell me something new.

mikey

iTrader: (6)

I'm at a loss Brent, sorry.

Team ZR-1

Reduced engine mod generally happens when the MAF and TB values do not agree with the PCM lookup tables and thus the TAC ( drive by wire) does not know what to set throttle angle to and to play it safe GM then sets to reduced engine mode.
Also if TPS sensor is flakey

If PCM was tuned flashed and it corrupted some value(s) this will occur OR the wrong flash was used and now the segment IDs are wrong.
If no other DTCs are reporting then if its not a unmetered air problem then PCM corrupted is next thing to check for.

One other thought is does the PCM scanner see lots of multi misfires (P0300) the new PCM needs a CKS relearn.

TEA Brent

There are no misfires, this thing will not run for longer than 30 seconds, but does not throw any misfires. That's gonna suck if I have to try another pcm, because this one has 0 miles and less than 5 min of run time (30 seconds at a time).