it shows code 28 #2 & 3, can anybody help ?

 

Are you sure its 28? That code is "Fault in transmission pressure switch assembly"

 

now that it could be it just got the tranny rebuilt and put in a shift kit does that mean anything or do i have to do some programming.

 

ok it's not the tranny pressure switch because that's only for the 94-95 LT-1
IT SHOWS in my haynes manual that it's a "quad module drive " can anybody tell me what that means.? thanks

 

yeah, I got that too. lol. DTC 28. does your turn on all of the time? when?

Mine usually goes on about 2 mins after car started, sometimes little less. Stays on until car shut off.

 

On a 1993, DTC 28 is "Quad-Driver Module (QDM) #3 circuit". It is a driver in the computer that controls several circuits. Without a 1993 manual, I can't tell you exactly what they are.

 

yup quad driver module thats the one i'll keep looking into the haynes manual but if someone out there know what that means let me know !


my friend has already erased it and keeps coming back using the snap on diagnostic tool. i was thinking of having alvin at pcm for less tune and have them erase it for good but we would like to know why it's throwin that code, mybe it's something simple to fix ? anybody

 

Be sure to check all your fuses under the hood. It could be something simple like that. It has to be related to some device, I just don't know which it is.

 

that could be true i'll check the one's by the door if there all ok. and not too sure about the relaY'S under the hood though

 

Ok, looking at my 93 Service Manual, QDM #3 controls the following relays:

A/C Clutch Control Relay
Primary Cooling Fan Relay
Secondary Cooling Fan relay

"DTC 28 will set if the ECM detects an improper voltage potential for 26 seconds"

Basically what the charts come down to is one of the following:

Faulty ECM connection
Open Relay
Fautly ECM
Grounded Relay

Cliff Notes: Check your relays listed above.

 

humn, where to even begin, going to try and throw the stock chip back in and see what happens.