Topic: Check Engine Light
in Forum: C4 General Discussion
Already a Member?
Click Here to Login
Not yet a Member?
Click Here to Register for Free!
Standard Member
Send PM
Lenexa, KS - USA
Joined: 9/25/2015
Posts: 1
Vette(s): 1991 Coupe, dark red with saddle interior, automatic. Original car, no customization.
My '91(standard coupe/automatic) has been thoroughly code checked and mechanically performs well within specs. The car is always driven in the overdrive position for the auto transmission and shifts properly. However, the "shift now" indicator lights comes on, on the dash right between 55-60 mph while accelerating, closely followed be the CES light on the control panel coming on and staying on until the end of the drive regardless of speeds up and down during the run. As I said, everything with the ignition, fuel system, EGR, etc., etc., has been checked out. Our theory now is that this is likely something within electronics getting some form of false message to trigger the shift indicator well after the transmission has already shifted up.
Let me hear from you if have shed any light on getting this distraction eliminated from an otherwise highly enjoyable ride.
SPONSOR AD:: (Our Sponsors help support C4VR)
Standard Member
Moderator
Send PM
Moderator
Duncanville, TX - USA
Joined: 3/18/2009
Posts: 2246
Vette(s): 1985 Coupe-L98/Auto,Bright Red/Carmine.
1974 Coupe-L48/4speed, Medium Red Metallic/Black Deluxe.
I don't understand why your automatic car would have the "shift now" light in the first place. I'd have to check into that. Have you tried pulling any codes out of it while the CES light is on? That would give you/us an idea of what the PCM thinks is going on, and would give you a starting place to diagnose the issue.
Joel Adams 
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Standard Member
Send PM
Crystal Springs, MS - USA
Joined: 7/29/2011
Posts: 34
Vette(s): 1973 Mille Miglia Red LS5
1981 Claret Red
1982 White
1985 Silver Metallic
1988 Yellow
1993 Torch Red ZR-1
1994 Torch Red Coupe LT1
1996 Dark Purple Metallic LT4
2000 Torch Red
2001 Light Pewter
2003 Z06 Millennium Yellow
2009 Atomic Orange
Check your vacuum lines...
1981 Dark Claret Metallic - SOLD
1982 White
94 Torch Red LT1
96 Dark Purple Metallic LT4
02 Black Convertible - SOLD
03 Millennium Yellow Z06
09 Atomic Orange Z51
09 Atomic Orange Z51
in Forum: C4 General Discussion
SPONSOR AD: (Our Sponsors help support C4VR)