What all does the car do in fail safe mode?
What all does the car do in fail safe mode? My tranny builder and I are going to try something different but the car will throw a code and prolly go to fail safe mode, I know the computer will have the car shifted to 3rd but what else does the computer do to the car. Does it mess with any fuel tables or and other kind of engine tables? Does it mess with anything other than the tranny? I am thinking of turning my Vaccum 4L60E into a Lenco 4L60E.
Is this something a tuner can take care of, I have a speed density tune with a local speedshop
Is this something a tuner can take care of, I have a speed density tune with a local speedshop
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
if it detects a problem with the O2 sensors it will go into open loop fueling ...
If it detects a problem w/the MAF sensor it will go into Speed Density (using MAP to determine fueling based on the VE Table)
When in speed density you also loose your high octane spark table w/the standard PCM OS and are forced into the low octane tables
If you are in just open loop not Speed Density then you'll run considerably rich at normal driving
On pre 2001 F-Body's with an auto it would also cause the trans pressure to go 100% all the time (not an issue on 01+)
If it detects a problem w/the MAF sensor it will go into Speed Density (using MAP to determine fueling based on the VE Table)
When in speed density you also loose your high octane spark table w/the standard PCM OS and are forced into the low octane tables
If you are in just open loop not Speed Density then you'll run considerably rich at normal driving
On pre 2001 F-Body's with an auto it would also cause the trans pressure to go 100% all the time (not an issue on 01+)
Originally Posted by horist
if it detects a problem with the O2 sensors it will go into open loop fueling ...
If it detects a problem w/the MAF sensor it will go into Speed Density (using MAP to determine fueling based on the VE Table)
When in speed density you also loose your high octane spark table w/the standard PCM OS and are forced into the low octane tables
If you are in just open loop not Speed Density then you'll run considerably rich at normal driving
On pre 2001 F-Body's with an auto it would also cause the trans pressure to go 100% all the time (not an issue on 01+)
If it detects a problem w/the MAF sensor it will go into Speed Density (using MAP to determine fueling based on the VE Table)
When in speed density you also loose your high octane spark table w/the standard PCM OS and are forced into the low octane tables
If you are in just open loop not Speed Density then you'll run considerably rich at normal driving
On pre 2001 F-Body's with an auto it would also cause the trans pressure to go 100% all the time (not an issue on 01+)
Its going to detect a problem from tranny(will have problems reading the shift solenoids), more than likely it will be a p1870 code. So depending on what the computer is reading is what the fail safe mode will do?
