Can someone tell me how to read and clear the diag codes on a 93 vert.
I have tried the serch but it doesnt seem to work.

Well I searched under ses codes and found a link.

Thanks




[Modified by Toecutter, 8:08 PM 6/14/2003]

 

I believe you have OBD-I so open the connection in the oreange wire near the battery or remove the negative battery lead for about one minute to clear the codes.

To read them, jumper ALDL pins A & B (upper right), turn the ignition On, and count the SES flashes, beginning with several "12"s, followed by each trouble code several times and terminated with several "12"s.

 

The early ALDL connector has room for 12 pins however only 7 are populated and of those we are only interested in Pin "A" and "B" for this procedure.

Remove the ALDL cover (in the unlikely event that there still is one in the automobile...they usually were lost early in the automobile's lifetime) and as you view the pins, you will find the top row fully populated whereas not all are populated pin on the bottom row.

On the top row (as you view the connector from the cockpit), the pin designators are F,E,D,C,B,A.


First locate your car's alcl
this component is located just below the instrument panel and
to the left of the center console. Remove the plastic cover
the first two slots to your right are the A & B slots for a drawing of
the alcl module's picture is added below.
The A slot is the diagnostic slot and the B slot is the ground
slot. insert the computer key into these slots (with the engine
off) this is very important...now only put the ignition key
to on ( not start !!!) the check engine light will display a
code 12 which is one flash followed by two flashes.
this code will be flashed three times ..followed by the
trouble code stored in your car's computer.
what ever the code is it will be flashed three times.
have a paper and pencil ready and write down the
code .

code 13 =1 flash followed by 3 flashes =>oxygen sensor
code 14 =1 flash followed by 4 flashes =>coolant sensor
code 15 =1 flash followed by 5 flashes =>coolant sensor
code 21 = 2 flashes followed by 1 flash =>throttle position sensor
code 22 = 2 flashes followed by 2 flashes=> throttle position sensor
code 23 = 2 flashes followed by 3 flashes=> manifold air temp sensor
code 24 = 2 flashes followed by 4 flashes=> vehicle speed sensor
code 25 = 2 flashes followed by 5 flashes=> manifold air temp sensor
code 32 =>egr system
code 33 =>map sensor
code 34 =>maf sensor
code 35 => idle air control
code 41 => cylinder select error
code 42 => electronic spark control
code 43 => electronic spark control
code 44 => lean exhaust
code 45 => rich exhaust
code 51 => PROM
code 52 => fuel calpak
code 53 => system over voltage
code 54 => fuel pump circuit
code 55 => ecm
code 62 => oil temp
please remember that if you have the computer key installed
in the alcl and you start the engine ( you will ruin the engine's computer
)
only put the ignition to on (not to start)
If you should get a check engine soon display.. you can use
the above procedure and codes to buy the right part
or at the very least to keep from getting taken for a ride
and be made to pay hight prices for some inexpensive
module that you could have installed yourself.
You never ask a barber if you need a haircut ..
so you have to be on guard they will see you comming
a mile away.
If your engine displays a trouble code ... your engine will
go into limp mode ..it will still run but very poorly.
you might be able to reset the computer if it will not start
( just to get home ) by disconnecting both battery cables
and re-installing them ...this is not recommended ..but if
you are stranded it might help unitl you get your car home
or to a repair shop..good luck
http://www.tonkabaygroup.com/vette/c4codes.html

http://www.c4vettes.com/ecm.htm

 

Thanks for the info.
The code is 36 MAF sensor.
I hope I dont sound dumb here but I cant find the MAF sensor on my friends LT1.
I have ported it on my LS1, But am havinfg trouble finding it on the C4.
Can someone point me in the right direction.
Its a 93 vert

Thanks


[Modified by Toecutter, 8:54 PM 6/14/2003]

 

http://www.c4vettes.com/sensorinformation.htm




[Modified by grumpyvette, 9:00 PM 6/14/2003]

 

Thanks for the link.
I kind of figured its on the front of the engine but the air cleaner seems to duct directly to the throttle body with nothing in between.
any other sugestions ? Maybe a picture?

Thanks
in advance

 

(Mass Air Flow) sensors are used on the TPI and more modern C-5 corvettes
The 1985 through 1989 C4 engines used a Bosch MAF sensor that heated the wire to 100 C. The 1994 and later C4 models used a AC/Delco MAF that heated the wire to 200 C. The amount of current required to reach the temperature is measured in each case. (Note: the LT-5 engine used in the ZR-1 used a speed density system and continued to use that system in 1994 and 1995 since the engines had already been made prior to the last two years of production. The ZR-1 therefore has no MAF even after Corvette went back to the MAF based system).

the 1990 through 1993 C4 models which were speed density based and used MAP/MAT sensors

 

The General switched from MAF to SD for the '90 & '91 L98 and ((I believe) for the '92 & '93 LT1 as well.

I which case your friend's '93 does not have a MAF in the intake air stream but rather a MAP sensor on the intake base.

 

I believe you are correct I, found these pictures of a C4 showing the MAF and my friends does not have one.

Now for the hard part why would the engine throw code 36 if there is no MAF?

 

Code 36 on a 93 is for a faulty high resolution pulse or extra low resolution pulse being detected. :steering:

 

Sorry for my ignorance but what does that mean.
The car keeps hunting for Idle and has no power.

Suggestions?

 

ttt

 

The ignition system supplies two timing inputs to the ECM, a high resolution signal (360 pulses per one chrankshaft revolution) and a low resolution signal (4 pulses per one crankshaft revolution). The ECM can determine if one of the timing inputs is not being recieved by comparing the two inputs. If the ECM detects the low resolution timing pulse without detecting the high resolution timing pulse, this code will set. The reference signals toggle between 0 and 5 volts ad the camshaft turns. Therefore, an open , a short to voltage, a short to ground, or a defective sensor inside the distributor can prevent the voltage from pulsing at the ECM. Possible problems are bad connections, bad ecm, or distributor failing ( on early LT1s this is a distinct possibility) :steering:

 

:iagree:

The simple interpertation: the opti MAY be on its way out. :D


[Modified by ittlfly, 7:03 PM 6/14/2003]

 

Thanks for your help.
I guess I have my work cut out for me.