several Check Engine Light codes (cel) at one time

[slag]

Working on my second 91 X, I am getting several Check Engine Light codes at once.

They are..

code 21--ECT out of range OR EDIS fault-CPS problem

code 24, ACT Sensor (brand new just replaced), or, EDIS fault-coil 1 primary circuit fault

lastly,

code 66--MAF sensor or VAF sensor-voltage too low, OR, transmission oil temperature sensor signal voltage is too low.

I bought a new coil pack but have not installed it. I dont think its going to fix the problem... What about replacing the CPS.. could that cause both code 21 and code 24 errors? What else should I be looking at? A new ignition control module is $144.00 (ouch). I dont want to be throwing money at this problem, but not really sure what is at fault here....

And the last one, I am going to clean the MAF and see if it clears up.

 

[Alec]

I'm on the same page you are: think cleaning the MAS and new CPS should work.

 

[Opera House]

I would be checking the temp sensor voltage since it is convienient. One of the wires should have 5V to ground. Looks like you are missing the common sensor 5V going to all of these sensors. Could be a connector problem on the computer or the bulkhead connector on the engine harness. Buying more parts would be a bad idea till you have checked this.

 

[slag]

went and bought the cps before i read opera house's reply....

Codes 21 and 24 are gone. i now get code 11 (system pass), then i get a code 66 still which is the good ole maf sensor error. the truck is idling high and low also, so either a good cleaning or a new maf..

let me cross my fingers..

Joe

 

[MrShorty]

First thing I might do is get a code list that is year/engine specific, so you know if that 21 is an ECT code or the EDIS fault.
My generic code list only lists 21 as an ECT code. That kind of 21 and the 24 (KOEO or KOER) are most often associated with running the self-test without warming the engine up.
Question on the 66: is it KOEO hard fault, KOER, or continuous memory?

 

[Positive Vibes]

Did you clean the MAF?

 

[slag]

YAY, No more CELs. A new MAF did it. Cleaning the old one did not fix the problem.. The vehicle is idling better than it ever has. Going to remove the IAC tomorrow and clean it and then run seafoam through the motor and call it done.

Still have to change the front wheel bearings on the drivers side and put all the interior back together.

Then buy 2 new tires and get an alignment and possibly change the shocks all around.. A good days job if I am not too busy with other things.