SES light help..
Thread Starter
Instructor
Joined: Sep 2002
Posts: 173
Likes: 0
From: Mustang Oklahoma
SES light help..
Ok, this happened on my way into the office this morning, so I haven't had a chance to pull the codes yet.
The symptoms...on my '94 LT1 M6 coupe.
The last few times I've driven the car, every now and then it will cut out for just a split second, hard to narrow down to fuel or ignition related. It did it more this morning. The SES light came on as well then went off a minute or so later. Once this happened, I cycled through the digital readouts to see what their status was. The analog gauges were in the normal ranges. What I noticed was that the digital temp readout was 142 degrees. This was after I had been driving for 10-15 minutes, and the analog gauge was reading 190ish as it should. The digital readout did not move up or down in stop and go traffice. 142 degrees. I got to the office, shut it off, came in for a few minutes, then went back out. It seemed harder to start the first time, then fired up. The digital gauge was still on 142 and the SES light was still on.
Could any of this be related to my cutting the mufflers off a couple of weeks ago? I haven't been able to drive the car much since then due to snow/ice around here.
Any ideas on what I might be looking at before I get the codes pulled this evening?
Thanks!
The symptoms...on my '94 LT1 M6 coupe.
The last few times I've driven the car, every now and then it will cut out for just a split second, hard to narrow down to fuel or ignition related. It did it more this morning. The SES light came on as well then went off a minute or so later. Once this happened, I cycled through the digital readouts to see what their status was. The analog gauges were in the normal ranges. What I noticed was that the digital temp readout was 142 degrees. This was after I had been driving for 10-15 minutes, and the analog gauge was reading 190ish as it should. The digital readout did not move up or down in stop and go traffice. 142 degrees. I got to the office, shut it off, came in for a few minutes, then went back out. It seemed harder to start the first time, then fired up. The digital gauge was still on 142 and the SES light was still on.
Could any of this be related to my cutting the mufflers off a couple of weeks ago? I haven't been able to drive the car much since then due to snow/ice around here.
Any ideas on what I might be looking at before I get the codes pulled this evening?
Thanks!
Thread Starter
Instructor
Joined: Sep 2002
Posts: 173
Likes: 0
From: Mustang Oklahoma
Well I know that! 
I'm just trying to get a feel for what I might be looking at so I don't sit here and think about it all day when it's going to be tonight before I can get home and check the codes.
I'm just trying to get a feel for what I might be looking at so I don't sit here and think about it all day when it's going to be tonight before I can get home and check the codes.
Team Owner
Joined: Oct 2000
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From: Fort Knox, KY
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Sorry, but only your ECM knows for sure. Why raise your B/P over unnecessary speculation and conjecture? Ain't no thing but a chicken wing. That's the attitude to have over material possessions...
Thread Starter
Instructor
Joined: Sep 2002
Posts: 173
Likes: 0
From: Mustang Oklahoma
Well I won't be home for a couple more hours to pull the codes, but there appears to be a definite relationship between the SES light and the digital temp readout showing 142.
While I was out earlier, the SES light was on and it was reading 142. The SES light went off, and the digital readout changed immediately to 190 and fluctuated appropriately.
Strange. I'll definitely post up the results of the code check this evening.
While I was out earlier, the SES light was on and it was reading 142. The SES light went off, and the digital readout changed immediately to 190 and fluctuated appropriately.
Strange. I'll definitely post up the results of the code check this evening.
Le Mans Master
Joined: Jul 1999
Posts: 8,683
Likes: 6
From: Phoenix AZ
Didn't you just replace the waterpump and opti? Doublecheck the coolant sensor connector at the front of the engine, it can get beat up pretty easy and it may not be seating properly. If that's the case it could be keeping you car from going into closed loop operation and it will run a little "off".
What's going on man?
What's going on man?
Thread Starter
Instructor
Joined: Sep 2002
Posts: 173
Likes: 0
From: Mustang Oklahoma
Didn't you just replace the waterpump and opti? Doublecheck the coolant sensor connector at the front of the engine, it can get beat up pretty easy and it may not be seating properly. If that's the case it could be keeping you car from going into closed loop operation and it will run a little "off".
What's going on man?
What's going on man?
I glanced at it this morning to make sure that it was plugged in, but I didn't check to see that it was seated. I'll do that before I head home. Not much goin' on here. Still doin' my thing. Might be out your way this June on my way back from the annual bike trip. Riding up to Seattle and then taking the leisurely way back through primo motorcycling roads in California.
Thread Starter
Instructor
Joined: Sep 2002
Posts: 173
Likes: 0
From: Mustang Oklahoma
Ok, got the code pulled.
DTC #15: Engine Coolant Temperature Sensor Circuit Voltage High. It came up as a history code. This morning is the first time it's done this with the SES light and the temp gauge fluctuation.
This code doesn't appear to be in my FSM. I found it online. This makes sense given the errant temperature reading on the digital gauge, but my question is *why* is the circuit voltage high?
I checked the plug. It was seated well, but I gave it a nudge just to make sure. Since I did that, the gauge has worked properly. Any ideas as to what might have happened? And why is this code not in Section 8D of my FSM ?
eta: I should also mention I just finished installing the new stereo goods. That's all cabled and grounded properly. The car is charging fine at 14.2+ volts. The amp I'm using is a 450 watt amp. I wonder if my *testing* of the system the last day or two has taxed the electrical system and that could be the issue? The battery seems fine. It starts the car quickly and easily each and every time. It is pushing 4 years old probably though.
DTC #15: Engine Coolant Temperature Sensor Circuit Voltage High. It came up as a history code. This morning is the first time it's done this with the SES light and the temp gauge fluctuation.
This code doesn't appear to be in my FSM. I found it online. This makes sense given the errant temperature reading on the digital gauge, but my question is *why* is the circuit voltage high?
I checked the plug. It was seated well, but I gave it a nudge just to make sure. Since I did that, the gauge has worked properly. Any ideas as to what might have happened? And why is this code not in Section 8D of my FSM ?
eta: I should also mention I just finished installing the new stereo goods. That's all cabled and grounded properly. The car is charging fine at 14.2+ volts. The amp I'm using is a 450 watt amp. I wonder if my *testing* of the system the last day or two has taxed the electrical system and that could be the issue? The battery seems fine. It starts the car quickly and easily each and every time. It is pushing 4 years old probably though.
Last edited by Gixster; Jan 26, 2007 at 08:43 PM.
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Thread Starter
Instructor
Joined: Sep 2002
Posts: 173
Likes: 0
From: Mustang Oklahoma
Ok more info, along with the errant coolant gauge readings, today I noticed that the volt reading was floating around 14.8 to 14.9. It spiked to 15.6, the car started bucking around a little, and then it stopped when the volts dropped back to 15.0.
Normal voltage is around 14.2 to 14.3. Does it sound like I have a voltage regulator going bad? I'm not sure how much voltage is too much.
Normal voltage is around 14.2 to 14.3. Does it sound like I have a voltage regulator going bad? I'm not sure how much voltage is too much.