LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

SES lights, OBDII emissions, et al.

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Old Mar 8, 2004 | 08:32 AM
  #1  
trax's Avatar
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Question SES lights, OBDII emissions, et al.

I still have the solenoids for my emissions stuff (AIR pump, AIR solenoid, EGR) laying around. Over the weekend I reconnected them (just the electrical plugs, not the tubing). The SES light is still on.

I looked at Shoebox's site and checked out the OBDII trouble codes. Since I haven't scanned the car yet, I just looked at the table and tried to find things that might apply to my car. Here are the only ones (besides emissions) that I could find. Will any of these set off the light?
--No Reverse lockout
--No CAGS connected
--No CAGS dash light
--AC delete

Barring a genuine mechanical problem this is all I can think of before I get the codes scanned.

--Edited for clarity --

Last edited by trax; Mar 8, 2004 at 03:25 PM.
Old Mar 8, 2004 | 10:58 AM
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Your codes don't appear to be in any way connected to "emissions", so not sure if I understand your question. Did you do a scan or not? Are the items below things you got codes for? Or are you just searching for why your SES light is still on?

--No Reverse lockout: Have you unplugged or deleted the reverse lockout? Is it possible you have a blown fuse on the circuit that supplies the reverse lockout? Not sure if this turns on the SES light.

--No CAGS connected: definitely lights the SES light. You need a "skip shift" eliminator, or a 2,200 ohm resistor in the connectro at the trans.

--No CAGS dash light: Did you unhook the wire for the skip shift light at the PCM connector? The code indicates this is disconnected.

--AC delete: If you have no A/C not sure what you do about the code. What code are you getting?

Now... since you have a 96, just connecting the emissions solenoids will not eliminate the trouble codes. There are detectors for flow in the EEC and AIR systems, and there is a diagnostic that looks for flow on the EGR system.

Might want to explain your question.
Old Mar 8, 2004 | 03:21 PM
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trax's Avatar
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Originally posted by Injuneer
Your codes don't appear to be in any way connected to "emissions", so not sure if I understand your question. Did you do a scan or not? Are the items below things you got codes for? Or are you just searching for why your SES light is still on?
I went to my local AutoZone only to discover that their scan tool is broken. Since the next nearest one is pretty far away I'm just trying to make some progress by looking at the trouble code table for what codes (barring those coming from a genuine mechanical problem) might apply to my car.


--No Reverse lockout: Have you unplugged or deleted the reverse lockout? Is it possible you have a blown fuse on the circuit that supplies the reverse lockout? Not sure if this turns on the SES light.

--No CAGS connected: definitely lights the SES light. You need a "skip shift" eliminator, or a 2,200 ohm resistor in the connectro at the trans.

--No CAGS dash light: Did you unhook the wire for the skip shift light at the PCM connector? The code indicates this is disconnected.
My bad... I forgot to mention that my car is a T56 conversion... so it doesn't have a CAGS dash light, or plugs for CAGS or reverse lockout. I will have to tap the pins accordingly.


Now... since you have a 96, just connecting the emissions solenoids will not eliminate the trouble codes. There are detectors for flow in the EEC and AIR systems, and there is a diagnostic that looks for flow on the EGR system.
This brings up a good question. Most of the emissions solenoids (EGR, AIR) are only two pins. Would that imply that flow is determined by fluctuation in resistance on the lines?

Thanks for the info!
Old Mar 8, 2004 | 03:32 PM
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You may be confusing two different devices.... solenoids and flow detectors. Just because something is black and has two wires doesn't mean it is a solenoid. In the EEC system, there is a solenoid and a flwo switch. It's likely both of them have two wires. The solenoid "opens" when it sees +12V. The flow switch simply "connects" when it sees flow or vacuum.

The AIR system only has the flow detectors as far as I know.

The EGR system has a solenoid, but the flow is detected by the PCM looking for a change in the MAP signal when the EGR valve is supposed to open.

If you have a T56 conversion, I would assume you flashed the PCM with an M6 program. That means you can connect the reverse lockout to the correct wire and it will work.... definitely a good idea. Makes getting it in reverse a lot easier. You can still put the resistor in the skip shift solenoid wire, and you can put a resistor in the "skip shift" bulb circuit to simulate the bulb.
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