Different "Limp Modes"

[JayArr]

Hi All

Does anyone know if there are different levels of Limp Mode?

When the engine is first started it's in "open loop" mode until it warms up. Some detected faults will light the CEL, which I understood puts the vehicle into "open loop" as well. Is the startup open loop the same as the CEL open loop?

JayArr

 

[Reprise]

Yes -- 'open loop' is open loop. There isn't a variation of it (or else GM / others would've likely named it as a variant, would be my guess).

I won't go into everything that happens / doesn't in open / closed loop -- that's pretty easily searchable, and no point in me typing it out here (on a phone, btw.) But to answer your question - only the two states - open / closed.

 

[freddyboy61]

Limp mode actually is a safety feature for the engine when particular faults are detected. One of these is a problem with the throttle body or accelerator pedal sensors. Limp mode will prevent the engine from going past a certain RPM level, I believe it is 3000 RPM.

 

[JayArr]

So is limp mode isn't the same as open loop it involves additional restrictions on the engine.
(I can go above 3000 RPM in open loop mode at startup)

I'll guess now that not all events that create a CEL mandate limp mode. Some just mandate open loop?