My 1995 SL2 twin cam is driving me crazy. Sometimes it runs fine, for a while. Sometimes it refuses to start and sometimes it will start but the idle runs up to about 2000, then slowly comes down to normal idle at which time it stalls cold dead and the SES light comes on. I've checked the error codes and they are #43- Master Relay Ground, Transaxle codes # 71 - second circuit ground open, 73 - Third circuit ground open, 76 - Fourth circuit ground open, 79 - Torque converter ground open. All seems to point to a bad ground connection. Would a bad ground cause the problems described and could anyone give me a cue as to where said ground connection would be located on the car?

 

Actually, it sounds like you may have two different problems ...

First thing I'd do, is replace the Engine Coolant Temperature Sensor (ECTS), and it's associated electrical connector. Purchase your parts from a "Saturn friendly" GM dealership. Cost of the parts will be about $40 bucks.

Now - with respect to the questionable ground connection ... there are several "splice packs" in different areas of your car, where the various grounds are connected. I'd look carefully at the grounding splice pack near the engine first, then the large one behind the instrument panel. Of course, it goes without saying, that you need to make sure that the main ground cable coming from the battery has not got a case of internal rot from battery acid getting under the insulation (it eats up the cable from the inside, like termites do to a 2x4 inside your house).

 

sorry but according to my text

DTC 43 - Knock sensor circuit open or shorted

As for the 70's codes are those from the SES flashing or the Shift to D2 light flashing? (just checking)

 

Thanks a lot for the help guys. The SES light flashed the #43 code and the 70 codes came from the HOT light. I got those error codes from an on-line site. I disconnected the negative battery post and checked the resistance with a meter from the battery end of the wire to a ground connection on the inside of the fender well near the fuse box and it showed no resistance at all so I would assume the body is well connected to the battery ground.
It snowed a little here last night and it turned a bit colder. I'm working outside so it may be a few days before I can get back to it.
Thanks again for the help, I'll post my results when possible.

 

Well I got back at it again. I’m working with a Haynes repair manual and have made the following checks. I checked several of the connections that go to ground through different splice packs with an ohm meter and got no resistance so I would assume they are OK

ECTS - I checked the voltage from the PCM and it is the required 5 volts. The book says to remove it and use a pan of hot water to simulate coolant temp and check resistances. If I remove it from the engine will I lose much coolant? I have not removed it yet.[/COLOR][/SIZE]

Idle Air Control Valve - The book says the voltage on the green/white and the green/black wires should fluctuate between 1.5 and 10.5 volts with the key on. All I’m getting is a steady 10.5 volts. Does that mean I have a problem with the PCM? The SES light came on again but does not stay on.

I checked the codes and now it gives a number 22 and 11 with the SES light and a 43 with the HOT light.

The book shows an A/TRANS RELAY in the UHJB but it is not there on my car. Is this the relay that error code 43 refers to? If so where can I find it? Yesterday I did those checks and tried to start it after reconnecting everything. It started after a couple of tries and seemed to run fine so I let it run for a half hour. The temp gauge went up to the proper reading and I shut it off and restarted it several times without a problem. Today I tried to start it and it was back to the same problem. If I keep trying it eventually starts, sometimes it continues running and sometimes it just idles down and shuts off. It seems to help if I hold the throttle wide open between starting attempts but I’m not sure if that is real or not.

 

I am answering in part to make a note to my self to come back and fill in gaps.
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Well I got back at it again. I’m working with a Haynes repair manual and have made the following checks.
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That is good, you bought a book. It should pay for itself in so many different ways!
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I checked several of the connections that go to ground through different splice packs with an ohm meter and got no resistance so I would assume they are OK
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As an electronic troubleshooter, this statement if interpreted wrong can lead to WRONG conclusions.
Believe me, been there and have the T shirt.
What is your definition of NO RESISTANCE and what scale did you use.
You should be using the lowest ohms scale on your meter
it should read something on the order of under 5 ohms.
Why that number? Because meter error has to be taken into consideration. It can be off by a couple of ohms. If you don't know that, not knowing it can lead to a wrong conclusion. Anything over 5 ohms, right or wrong can be a big problem. In theory, zero or 0 ohms. And if you are not using the lowest ohms reading of your meter, you can not read ohms that small.
If all of the above are taken care of, forget I asked.
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The heat sensors (the two at the drivers side end of the cylinder head) I think there were two in 95, as in 94 also and that is what I have.
One is used for the computor to monitor engine condition, the other is used to turn on the electric fan. These functions were incorporated into one sensor and then computor controlled in later Saturns and they have been problematic over the years. Starting with the wrong sensors installed at the factory and un-detected for about 10 years or so, this lead to the wrong sensors also being manufactured for aftermarket.
Fast forwarding, many times the problems were ignored or lived with with out a proper repair. Cars were probably sold due to them being bad causing drivability problems. Fast forward again to today. You are probably having a problem with one or both of them. The only sure source for the proper sensors is a Saturn friendly GM dealer that WILL supply you with the proper ones. Buying one aftermarket is not a sure thing that you will get the right ones.
Some if not all of the symptoms you are describing can be attributed to these sensors.
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If the engine is cold, you will not loose much in the way of coolant by removing them.
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It's getting close to my supper, I will come back later and look up the code #'s you have reported in my Mitchels documentation.

 

Did you replace the ETCS and connector? If so what one did you replace?

 

I checked the codes and now it gives a number 22 and 11 with the SES light and a 43 with the HOT light.
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TPS=Throttle Position Sensor (22). 0.4 volts at PCM when throttle is closed
4.5 to 4.9 volts at PCM when throttle is wide open (WO)
Greater than 4.9 volts = error code.
Knock Sensor (43) An open in the knock sensor would give 5 volts at PCM
A short in the knock sensor would give low to near zero volts at PCM
Normal resistance reading accross knoock sensor is 3300 to 4500 ohms at the sensor.
If the sensor is not tight in it's threads will give intermittent readings.
Thus codes.

The >11<? I don't know what it is.

 

Just a note here -- the "11 CODE" is the start/stop point in the list. It gives you a reference point so you are not counting the same code error twice. If you hook up, and see only the "11 CODE", it means all is well ........