Code 36
Thread Starter
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Code 36
Stumped.......
1992 vette started up after a 2 month rest on a tender. Started fine, ran fine, no problems other than a steady code 36 light and fans on constantly. Again, vette runs and starts nicely.
Can't clear code with scanner, or by battery disconnect.
I understand the high and low resolutions that cause a 36, but don't understand why the fans are always on. Is there a connection?
One hint is to check the pigtail connector from the distributor to the main harness for 'opens'. Can't locate locate pigtail connector.
'Check engine light' is steady.
Have not checked the ground connection below battery.
Just looking for shortcuts before following the 'diagnostic tree':
1992 vette started up after a 2 month rest on a tender. Started fine, ran fine, no problems other than a steady code 36 light and fans on constantly. Again, vette runs and starts nicely.
Can't clear code with scanner, or by battery disconnect.
I understand the high and low resolutions that cause a 36, but don't understand why the fans are always on. Is there a connection?
One hint is to check the pigtail connector from the distributor to the main harness for 'opens'. Can't locate locate pigtail connector.
'Check engine light' is steady.
Have not checked the ground connection below battery.
Just looking for shortcuts before following the 'diagnostic tree':
Thread Starter
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Originally Posted by bassackwards
The fans are on because the check engine light is on. You need a new optispark
The vette runs just fine..... had an opti fail before on my '93, and no codes, vette just quit running. Opti is OEM with only 1K miles.
You may be correct that it is a failing opti, but I'm hoping for a ground problem.
Thread Starter
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
No hesitation in starting, idles perfect, accelerates just fine. ?????
Thread Starter
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Will have to run diagnostics.... FSM suggests under one condition the ECM may be the problem, and a replacement ECM may be difficult to locate.
Racer
Joined: Dec 2012
Posts: 301
Likes: 2
From: NY
My fans seemed like they were running all the time until I realized that when the climate control is activated in any mode or temp setting it triggers the fans to cycle on and off frequently. I thought it may be what you were experiencing.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Thread Starter
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Racer
Joined: Dec 2012
Posts: 301
Likes: 2
From: NY
Some good reading here. I purchased a TPI computer and harness from them for my Jeep and it runs awesome. Poke around if you're interested.
http://www.hotrodlane.cc/New%20LT%20...ge.html#LTtech
http://www.hotrodlane.cc/New%20LT%20...ge.html#LTtech
Thread Starter
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Some good reading here. I purchased a TPI computer and harness from them for my Jeep and it runs awesome. Poke around if you're interested.
http://www.hotrodlane.cc/New%20LT%20...ge.html#LTtech
http://www.hotrodlane.cc/New%20LT%20...ge.html#LTtech
Racer
Joined: Dec 2012
Posts: 301
Likes: 2
From: NY
Thread Starter
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Thread Starter
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Just an FYI to close this thread........
After learning where the ignition test connector is located, I was
able to perform the voltage test as displayed in the FSM diagram
in my first post.
The tests are positive and easy to conduct...... ECM and wire/ground
tested OK, and there was a short to voltage on high resolution at the opti.
Again, vette started, idled, and accelerated perfectly (exception: starting was immediate, but not as smooth before code 36 appeared).
Solution: new Sac City opti ($149), new AC Delco water pump ($101), labor from a shop that allows owner to provide parts ($350).
I'm pleased.
After learning where the ignition test connector is located, I was
able to perform the voltage test as displayed in the FSM diagram
in my first post.
The tests are positive and easy to conduct...... ECM and wire/ground
tested OK, and there was a short to voltage on high resolution at the opti.
Again, vette started, idled, and accelerated perfectly (exception: starting was immediate, but not as smooth before code 36 appeared).
Solution: new Sac City opti ($149), new AC Delco water pump ($101), labor from a shop that allows owner to provide parts ($350).
I'm pleased.
Thread Starter
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
but it was obvious that he was mechanically able, but very poor in cosmetic detail, and not Corvette smart, even though he owns a '57 stored in his barn.
I'm quite sure the water pump was not replaced with the opti, so that may be the problem (64K miles). I believe the opti was an OEM opti.