Guide: Checking the Engine Trouble Codes
Pictures and Guide by Joshua Langevin
This is a step by step guide to checking the
engine trouble codes in your SHO. Remember that just because your CEL (Check
Engine Light) isn't on does not mean that there are no codes stored by your
computer. If you are having troubles with your SHO, this is the first place
you want to go.
There are three tests, KOEO (Key On Engine
Off), KOER (Key On Engine Running), and the Cylinder Balance Test.
1. Make sure the engine is warmed up to normal
temperature. The car should be in neutral, parking brake set. Shut the heater/AC
off. Locate these two plugs under the hood, on the passenger side of the firewall.
They have covers over them that you must remove.
2. Now use a jumper wire and connect the upper-right
pin on the black plug with the large pin in the grey plug, like so. A paperclip
seems to be a popular choice. :)
For a better look at where this jumper wire
goes, look at this diagram. Connect the jumper to the red dot on the connectors.
3. Now jump into the car, and make sure you
have a pad and pencil ready to jot down the codes. Now turn the key to "On",
but do not start the car. You will see the CEL blink and hear the whirr
of the cooling fan being tested as well as the fuel pump. Then the codes
will start being displayed.
The codes are displayed by the CEL in flashes
separated by pauses. If you have a Gen I (89-91) there will be two sets of
flashes, if you have a Gen II (92-95) there will be three sets. As an example,
a code of 256 would look like this: *flash*flash* PAUSE *flash*flash*flash*flash*flash* PAUSE *flash*flash*flash*flash*flash*flash*.
The common code 114 would look something like this:
It can be a little confusing at first, but
the car will display the codes twice. Then it will flash once, and then move
on to the stored codes. These are the codes that have been stored by the computer but may or may not have found when testing.
KOER (Key On
Now, start the engine. The CEL will blink
3 times. Watch the RPM guage carefully, and when you see the RPMs rising (the
computer is advancing the timing) then follow these steps: (this is so the
computer know these things are working)
1. Turn the steering wheel 1/2 turn to the
right and then to the left.
In a moment the RPMs will go back down and
the check engine light will flash once. Now step on the gas for just a second
(at least 1/4 way down). Now the codes will be displayed.
Clearing the Engine
Generally, the best way to clear your codes is to disconnect
your battery for at least 10 minutes.
Cylinder Balance Test
This is to make sure that all of your cylinders
are working right. After you have run the above test, press the gas pedal
down again at least 1/2 way, just for a second. The RPM guage will move and
the engine will start running a little rough. This is because your computer
shut one of the cylinders off. It will do this 5 more times, once for each
cylinder. Then it will display the codes.
Two Digit EEC Codes (89-91 SHO)
Cyinder Balance Codes
10 Problem with cylinder
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