so 2000 saturn s series I have a service maintenance light (service/wrench) comes on shows 0 codes but I erase the "0" code car runs better. If I dont clear the code with the code reader it shifts hard . any suggestions what it could be? I have no other codes come up, Transmission fluid is fine.

 

Wrench light most often comes on for a dash bulb that's out. Observe very carefully at key on bulb check.

Wrench light does not set for codes.

Code reader or code scanner?
Code readers usually only read emissions codes and turn on the serv eng soon see.
Code scanners can read addl codes, like body codes (BCM), chassis codes, communication codes, and, srs, TCM....

1999 and up s Series were the first s cars to have bcms. Might be something awry there.

However, you can't clear a code you can't read ---or can you?

Folks, does the clear all codes just wipe the memory that stores recent faults, whether or not you can read them B, C, X?
Or does it just clear the ones it can read?

Mileage? Any other issues with trans?

 

A wrench light will show on an L series car when the transmission faults the pressure solenoid circuit. The transmission goes into failsafe mode and raises line pressure to protect itself. A key cycle resets the transmission and all is well until the next fault. I have only had this occur on an L300 which has a stand alone transmission module, never on the several L200 cars that I have owned. The L200 pcm contains both engine and transmission control in one unit. The transmissions are slightly different models on both L series car models, the 300 series has more clutch plates.
I have zero experience with the S series cars.

 

Have you ever replaced the ECTS? If not, you might consider that. It's on the front of the cylinder head on the drivers side. DO NOT purchase one from any of the chain parts stores. They won't work. They're generic and not calibrated correctly. You'll need to get one from a GM dealership along with a new pigtail. You'll have to splice the pigtail in and don't half-*** it. Solder the wires and use some heat shrink on the connections to keep moisture out.

 

I have never replaced this and I don't know what it is?

 

It's a sensor for the temp of the coolant in the engine. These things are known to get flaky in the 1.9 engines and cause all kinds of issues, one of which is how the transmission shifts. Electronic Coolant Temperature Sensor. Maybe derf has a part # handy as he keeps track of things like this. He's a sharp dude and actually owns 2 S-series cars. I'm not sure if there's a difference between the SOHC and DOHC sensors or not. I don't THINK so, but better safe than sorry. What say you, derf? Of course, I could be WAAAAAYYY off base here as I'm NOT a mechanic. You may have problems with the shift solenoids in the valve body on the transmission. I'm guessing you have the crappy TAAT4 automatic transmission.

 

Did a bit more research.

The Service wrench light is illuminated by a specific set of dealer-defined situations. So it can illuminate for multipole reasons. Some of those reported include:

--blown dash bulbs -- including the Service Engine Soon light)
---low brake fluid (throws a C code (chassis code as defined by the manufacturer)
---Motor on Cooling fan by the radiator having issues (Check 30A Cooling Fan fuse). If the fuse is blown replace it. If the fuse keeps blowing (not necessarily immediately) replace the fan motor / fan assembly


Since it can throw C codes, it stands to reason that a full featured Scan tool that reads B C and X codes in addition to the P codes MAY lead you directly to the source.
Sounds like it is possibly a dealer transmission code hiding in there (manufacturer-defined).

Autozone and similar scans will not display anything other than P codes.

The tool you are using apparently knows it's there but is not programmed to read and display the non-P code....Interesting

Use a full-featured scan tool to scan it and you will very likely find the issue.


----------


17 yrs on this forum, driving S cars, and I learned something new today about S cars.
There's always more to learn.......

 

Here's a video from richpin on youtube. richpin has a LOT of great Saturn how to videos. Check him out.

 

thank you I will need to take it to a dealer and have it checked out it always happens with quick stops and fast take offs so I try to avoid those as much as possible.