only error code is H26, yet "Service Engine Soon" light is on
Thread Starter
Cruising
Joined: Aug 2012
Posts: 13
Likes: 0
only error code is H26, yet "Service Engine Soon" light is on
I jumpered the diagnostic connector, and I get the diagnostics readout. What I don't understand is that the "Service Engine Soon" light on the panel is on, yet the only code that appears is H26. How can an old code cause the SES warning to light?
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
As in ,it was present when the key was 1st turned on ( when the ECM was doing it's start up self checks ) but is not there now ?
Clear the codes and see if it comes back
Thread Starter
Cruising
Joined: Aug 2012
Posts: 13
Likes: 0
OK, cleared the codes
and the 'H' code still shows up. The only other thing worth mentioning is the "Change Oil" indicator is on. Could this be causing the "Service Engine Soon" indicator to light?
FWIW, I tried to turn off this light with the following procedure: press the ENG MET button, release, press it again, release, then press & hold the GUAGES button until the light goes off. The procedure didn't work on my '93. How do you turn off this indicator on a '93?
And thanks, vetteoz, for your input!
FWIW, I tried to turn off this light with the following procedure: press the ENG MET button, release, press it again, release, then press & hold the GUAGES button until the light goes off. The procedure didn't work on my '93. How do you turn off this indicator on a '93?
And thanks, vetteoz, for your input!
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
Ignore the "history" indication, troubleshoot the code 26 (quad driver circuit #1) using the FSM. (The EGR and canister purge solenoids are common failure items. )
My experience with my 93 has been that ALL codes have the "H" designation even when they currently exist, hope that helps.
My experience with my 93 has been that ALL codes have the "H" designation even when they currently exist, hope that helps.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
You turn it off by fixing the problem.
Error code 26 is a quad driver fault. The quad driver is inside the ECM and is used by the ECM to turn on relays and solenoids. The error code is usually caused by a shorted relay, solenoid or wiring. You need to go to the FSM to determine which ones to look at.
Error code 26 is a quad driver fault. The quad driver is inside the ECM and is used by the ECM to turn on relays and solenoids. The error code is usually caused by a shorted relay, solenoid or wiring. You need to go to the FSM to determine which ones to look at.
Thread Starter
Cruising
Joined: Aug 2012
Posts: 13
Likes: 0
Thanks, guys!
Knowing that the H preceding the error code doesn't always indicate a past problem is a great help. I'm looking at
http://forums.corvetteforum.com/c4-t...river-4-a.html
now.
http://forums.corvetteforum.com/c4-t...river-4-a.html
now.
Thread Starter
Cruising
Joined: Aug 2012
Posts: 13
Likes: 0
Bingo! Found the problem - it was the first thing I checked. A previous mechanic had unplugged the EGR, for some reason, and never plugged it back in. Once it was, the engine ran strong, no warning lights, and it passed the emissions test.
Thanks for all of your help!
Thanks for all of your help!
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