2006 22Ve in limp mode

[johnny340]

5.7 L Vortec engine

When the key is on, the buzzer sounds continuously. Once started, buzzer still on and engine won't rev up. No throttle response. (Limp Mode)
I'm trying to figure out what has put it in limp mode. All fluids at proper levels and gauges look correct. Knock sensor is connected. Good batteries with good grounds. I've read about bad throttle position potentiometers and tested it with the following readings:
5kV at idle to 1.3kV at full throttle
Is this a normal reading?
What else should I check for that would cause limp mode?
Many thanks!

[chpthril]

I'm guessing that you have the factory EIDB dual battery system? What is the static (at rest) battery voltage of each battery. Both may test "good" but a difference in voltage can send the ECM into limp-mode.

[johnny340]

Yes, factory EIDB.


I've got 12.37 V on the cranking battery and 12.62 V on the deep cycle one.
Is that close enough?
Thanks in advance for your replies!

[chpthril]

Yes, factory EIDB.


I've got 12.37 V on the cranking battery and 12.62 V on the deep cycle one.
Is that close enough?
Thanks in advance for your replies!

The cranking is about 75% discharged and the deep-cycle is about 50% discharged.

That spread may be enough to cause a code 81 and send it into limp mode.

[Tanner]

You got 2 issues here.

1. As Chp said your batteries could very easily be tripping a code 81 due to that voltage difference.

2. Your also setting a code 81 due to that voltage drop on the potentiometer. Dropping from 5kV down to 1kV indicates it's going bad, but if for whatever reason you got the #'s reversed, meaning it climbs to 5kV's then it's doing it's job. Call Harvey and see if he has any in stock yet.

Good luck!

[22veguy]

Is your 2006 throttle by wire? I'm not sure when Tige cut-in the MEFI 5. If it is MEFI 5 / throttle by wire then you will have 2 sensors at the throttle. (PPS 1 & PPS 2)
The PPS 1 signal voltage is pulled up to the reference voltage as the throttle opens, from ~0.45 volts at closed throttle to ~4.18 volts at wide open throttle (WOT). The PPS 2 signal voltage is pulled down to the reference voltage as the throttle opens, from ~4.55 volts at closed throttle to ~0.82 volts at WOT.

Might explain why voltages look reversed based on MEFI 4.

[Tanner]

Is your 2006 throttle by wire? I'm not sure when Tige cut-in the MEFI 5. If it is MEFI 5 / throttle by wire then you will have 2 sensors at the throttle. (PPS 1 & PPS 2)
The PPS 1 signal voltage is pulled up to the reference voltage as the throttle opens, from ~0.45 volts at closed throttle to ~4.18 volts at wide open throttle (WOT). The PPS 2 signal voltage is pulled down to the reference voltage as the throttle opens, from ~4.55 volts at closed throttle to ~0.82 volts at WOT.

Might explain why voltages look reversed based on MEFI 4.

I'm pretty sure the 06' is still MEFI3, I know mine is .... I don't think MEFI4 even got cut in until 07'. Let alone MEFI5

[22veguy]

My '07 22Ve is MEFI 5. Maybe they skipped over 4??

[chpthril]

Cant tell you what Gen MEFI it is, but an 06 Ve with a 340 MP is TBW.

[dom w. forte]

2006 is a mefi 4, 2007 is mefi 5.

[johnny340]

Yea, I only see the one sensor at the throttle. I've got a guy checking codes now. Will post his findings.