paper clip trick for 88? error codes
Thread Starter
2nd Gear
Joined: Apr 2006
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paper clip trick for 88? error codes
I would appreciate it if someone would tell me how to display error codes on an 88 with a paper clip. I have done a search but didn't come up with the exact question and I hesitate to experiment. Thanks, John
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Insert the paper clip bent into a "U" shape between the A and B terminals of the ALDL connector, located above the driver's right knee, on the bottom of the carpeted panel.
This site explains how the flashes are read.
http://corvettebuyers.com/c4vettes/ecm.htm
This site explains how the flashes are read.
http://corvettebuyers.com/c4vettes/ecm.htm
Drifting
Joined: Feb 2005
Posts: 1,592
Likes: 3
From: St Louis MO
If you have an Autozone nearby, check with them to see if they are still giving away a free "jumper key'. A paper clip will work but the key is handy to have and easier to use.
Last edited by PierEagle; May 3, 2006 at 12:21 AM.
Drifting
Joined: May 1999
Posts: 1,478
Likes: 3
From: Sacramento, CA Money can't buy happiness - but it's more comfortable to cry in a Corvette than a Yugo.
A list of the codes and what they mean can be found here:
http://www.corvettebuyers.com/c4vettes/ecm.htm
You jumper the ALDL with the engine off and count the flashes to get the codes as explained by the site that 86PACER posted. That is the Diagnostic Mode.
You can also use the jumper with the engine on and running to put your ECM into Field Service mode and see if the ECM is going into closed loop. From the 88 FSM which states in Section 6E, page 6E-5:
If the Diagnostic terminal is grounded with the engine running, the system will enter Field Service mode.
... In "Open Loop" the "Service Engine Soon" light flashes two and one-half times per second.
In "Closed Loop" the light flashes once per second. Also, in "Closed Loop" the light will stay OUT most of the time if the system is too lean. It will stay ON most of the time if the system is too rich.
http://www.corvettebuyers.com/c4vettes/ecm.htm
You jumper the ALDL with the engine off and count the flashes to get the codes as explained by the site that 86PACER posted. That is the Diagnostic Mode.
You can also use the jumper with the engine on and running to put your ECM into Field Service mode and see if the ECM is going into closed loop. From the 88 FSM which states in Section 6E, page 6E-5:
If the Diagnostic terminal is grounded with the engine running, the system will enter Field Service mode.
... In "Open Loop" the "Service Engine Soon" light flashes two and one-half times per second.
In "Closed Loop" the light flashes once per second. Also, in "Closed Loop" the light will stay OUT most of the time if the system is too lean. It will stay ON most of the time if the system is too rich.
Team Owner
Joined: Jan 2003
Posts: 20,298
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From: Summerland B.C. Canada
Le Mans Master
Joined: Feb 2006
Posts: 8,753
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From: Louisiana
Originally Posted by PierEagle
If you have an Autozone nearby, check with them to see if they are still giving away a free "jumper key'. A paper clip will work but the key is handy to have and easier to use.
Got mine from there. It makes it easier and its more stable when in Field Service Mode. They had a box of them an the guy said they never use them anymore.
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Drifting
Joined: May 1999
Posts: 1,478
Likes: 3
From: Sacramento, CA Money can't buy happiness - but it's more comfortable to cry in a Corvette than a Yugo.
Originally Posted by GRX
Make sure you ground yourself by touching a cold water pipe before doing this. Static electricity can destroy the ECM.
Excellent advice if handling the ECM, as static electricity can easily damage it. In this case the procedure being done is grounding the ECM at terminal B to A (ground), so it is pretty hard to hurt the ECM with static electricity. Now if you appen to have an arc-welder or some 440Hz equiptment running close by, take the exta precaution.
Last edited by Mike_88Z51; May 3, 2006 at 02:25 PM.
Drifting
Joined: May 2004
Posts: 1,743
Likes: 0
From: Ohio
Originally Posted by 86PACER
Insert the paper clip bent into a "U" shape between the A and B terminals of the ALDL connector, located above the driver's right knee, on the bottom of the carpeted panel.
This site explains how the flashes are read.
http://corvettebuyers.com/c4vettes/ecm.htm
This site explains how the flashes are read.
http://corvettebuyers.com/c4vettes/ecm.htm
my '94 has the 16 pin connector. What's the method for this one?
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
I strongly suggest a visit to Auto Zone on the ECM "key" as they call it. I got a handful of these a few months ago by asking for one key......and they are free. Hellava deal!!! 
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by mudslide
lucy splain this cold water thing
RACE ON!!!
Race Director
Joined: Dec 2000
Posts: 17,551
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From: El Paso Texas
Originally Posted by CFI-EFI
Many hot water heaters have the hot water outlet pipe isolated from the cold water inlet, making for an indirect and a poor connection to "ground". It's that simple.
RACE ON!!!
RACE ON!!!
