Code and no SES....Why?
Thread Starter
Launching!
Joined: Jan 2002
Posts: 216
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From: MD
Code and no SES....Why? Alright, this may be a stupid question, but I'm going to ask it anyway.
I had codes: 02 sensor circuit malfunction, and 02 sensor circuit slow to respond.
Now, if the front 02 was malfunctioning, which can cause the car to run poorly, right, why no SES light? Without A-tap, I would never have known this. Just thought an SES light would have notified me sooner.
So I wonder, what it takes for an SES light, or no SES light? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
And I'm all fixed for now. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I had codes: 02 sensor circuit malfunction, and 02 sensor circuit slow to respond.
Now, if the front 02 was malfunctioning, which can cause the car to run poorly, right, why no SES light? Without A-tap, I would never have known this. Just thought an SES light would have notified me sooner.
So I wonder, what it takes for an SES light, or no SES light? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
And I'm all fixed for now. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Joined: Nov 2001
Posts: 1,707
Likes: 33
From: Anderson, Indiana
Re: Code and no SES....Why? No, not a stupid question.
The diagnostic trouble codes break down by order of importance. If a trouble code is defined as "very important", the SES light comes on immediately. If it is important, but not quite that important, the system will see if the problem still exists the next time you start the car. If the problem is still there, the light comes on. If the problem is not important enough to warn the driver, but is useful as "information only", the code is stored but the light never comes on. These codes help the service technician diagnose problems when the car is in for maintenance, but they don't want to scare the driver by turning on the light.
Your problem may not be solved at all. Drive around for awhile and A-tap again to see if the codes return. If so, the problems are real, just not so crucial that the PCM can't still control the engine acceptably.
The diagnostic trouble codes break down by order of importance. If a trouble code is defined as "very important", the SES light comes on immediately. If it is important, but not quite that important, the system will see if the problem still exists the next time you start the car. If the problem is still there, the light comes on. If the problem is not important enough to warn the driver, but is useful as "information only", the code is stored but the light never comes on. These codes help the service technician diagnose problems when the car is in for maintenance, but they don't want to scare the driver by turning on the light.
Your problem may not be solved at all. Drive around for awhile and A-tap again to see if the codes return. If so, the problems are real, just not so crucial that the PCM can't still control the engine acceptably.
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91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
Joined: Nov 2001
Posts: 34,628
Likes: 2,543
From: Schiller Park, ILL Member: #317
Re: Code and no SES....Why? This is correct. I get a P0748 code all the time now since I’ve gone to a vacuum modulated trans. The code is for Pressure Control Solenoid, which is because of the vacuum conversion. So I know that nothing is wrong, the PCM is just weirded out by the vacuum modulator. But the code never sets a light, ever. It’s just there every time I check it.
TECH Senior Member
Joined: Nov 2001
Posts: 8,423
Likes: 0
From: Friendswood,TX
Re: Code and no SES....Why? What about the actron scantool will it read all the codes or just SES codes? I don't have autotap yet.
<small>[ May 15, 2002, 04:44 PM: Message edited by: Toxic Texan ]</small>
<small>[ May 15, 2002, 04:44 PM: Message edited by: Toxic Texan ]</small>
