2003 L300 6 cyl SES light comes on and won't store code

[fsoltero]

Ok folks here's my first post. I own a 2003 L300 with the 6 cylinder engine. The SES light has come on several times solid and does not generate an error code in the computer. Once I shut the vehicle off for a while and turn it back on the light goes away. While the SES light is on the vehicle shifts "hard" and jumps into gear. The transmission filter and fluid has been replaced twice in accordance with maintenance guidelines. There are currently 86,000 miles on the vehicle and it is currently at the dealer for evaluation. This problem began about 1 month ago and is intermittent. Please advise.

[beensmoked]

Originally Posted by fsoltero

Ok folks here's my first post. I own a 2003 L300 with the 6 cylinder engine. The SES light has come on several times solid and does not generate an error code in the computer. Once I shut the vehicle off for a while and turn it back on the light goes away. While the SES light is on the vehicle shifts "hard" and jumps into gear. The transmission filter and fluid has been replaced twice in accordance with maintenance guidelines. There are currently 86,000 miles on the vehicle and it is currently at the dealer for evaluation. This problem began about 1 month ago and is intermittent. Please advise.

it's not your SES light. It's your Service Wrench and even if ur driving really slow it shifts hard right? It's probably your MAF sensor.

[fsoltero]

Your right it is the service wrench light. The light has come on and the car begins to shift hard at both high (70 mph) and low speeds (40 mph). Why wouldnt the Maf cause the BCM to store an error code? Please advise. Thanks!!

[beensmoked]

it's kinda hard to explain but the MAF sensor monitors air flow. And transmissions now aday do arn't used by hydralics. They shift using pressure building up. If the tranmissions thinks it's gettin more or less air flow then it actually is. It will shift incorrectly. And if it has been happening recenlty. Your SES light will soon.

[fdryer]

Although I'm very limited in background info for why the MAF sensor is affecting the transmission shift points I would have to go along with beensmoked's personal experience in this matter. There seems to be little on this forum covering the MAF sensor specifically affecting transmission shifts but there are general symptoms to be considered and erratic shifting is one of them. The MAF sensor will indirectly affect transmission shifting based on many sensor inputs such as the CPS, IAT, ECTS, and TPS, as determined by the transmission control module and engine control module in concert with each other. A nightmare to say the least and many things to consider.

There are three (3) DTC's that are listed in the factory service manuals (FSM) for the L300, m-y '02-'03;

1-DTC 0101; if the MAF sensor airflow value is too far out of agreement from the ECM calculated airflow value (based on MAP, engine speed, and TP angle).
2-DTC 0102; if MAF sensor signal voltage is less than 0.14 volts (less than 0.0 g/s).
3-DTC 0103; if MAF sensor signal voltage is greater than 4.8 volts.

It is entirely possible that even when there aren't any codes set by the BCM that there are many problems that experienced Saturn techs and DIY'ers have found and shared on these forums. In general one can't expect everything as easily as a code to pop up and point to the problem when in fact sometimes the codes point in the wrong direction if there are any codes to begin with!? That's where experience comes into play for anyone seriously having a desire to understand computers, diagnostic codes, translating these codes from basic understanding of engine dynamics and reading between the lines, so to speak. It can be confusing for the occasional DIY'er not familiar with code reading, lack of codes, but that's not your fault as you've found a place to share your lack of understanding.

The three codes for our L-series, covering the possible MAF sensor problem are the most likely failures as determined by electronics logic, flow charting to characterize it differently, and not from real world problems. I haven't included anymore text following the DTC's because its lengthy and detailed. In essence, each DTC mentions to check the wiring, voltages, connectors, possible air leaks in and around the MAF sensor that can corrupt the measuring of airflow and lead to a DTC being generated. This would be the false generation of a code due to loose clamps holding the MAF sensor, a crash occuring destroying the integrity of the airtight seal between the MAF sensor and the intake manifold, use of aftermarket air filtration systems with oil oversoaking of the permanent filter element that deposits excess oil onto the MAF sensor element and destroying the effectiveness of the MAF sensor. Simply replacing the air filter w/o properly checking for air leaks after the MAF sensor body to the rest of the intake air system could conceiveably turn on a diagnostic code while all one did was to replace the air filter.

The last two codes can be loosely interpreted as if the MAF sensor were disconnected or (as I know from personal experience) if the fine element inside the MAF sensor were broken. Based on a co-worker's description of his symptoms we were able to determine that his MAF sensor failed on a Chevy Transport, intermittently, when driving. This was because; 1-he's an electronic's tech and able to measure the internal resistance of his intermittent MAF sensor, 2-could duplicate the symptoms easily just by driving normally and noticing when the vehicle died and re-starting after a few minutes of a cool down period, 3) my Bosch EFI manual detailing each part of EFI systems, and finally finding the intermittent failed MAF sensor, on another engine dying incident while at the side of the road when the MAF sensor stayed in its failed open resistance mode before it had a chance to cool down and work again. A $125 part that cured the intermittent car dying routine.

Of course this incident doesn't fit your scenario as yours is wholly different and I have a personal interest in how this turns out as I too have the same m-y as you. Unfortunately, there aren't too many choices unless a Saturn tech intervenes and offers a better solution. The choices at this point are to go to the dealer service for their opinion, buy a MAF sensor from an online site such as saturnparts.net or *.com and take the chance that beensmoked's opinion is right-on to save the diagnostic fees if any and if Saturn can find any diagnostic code(s) and/or pay them to find other issues with your car that may or may not cure your shift problem. The simple things to do are to go over to your engine, visually inspect the associated wiring and look for loose, cracked, broken wires, plastic shrouds not connected or clamps loose, missing, broken, vacuum leaks, anything that may look out of place in the engine compartment. Sometimes the obvious will reveal itself with just a little casual observation or poking around.

[beensmoked]

if changing the MAF sensor doesn't fix the problem. It's most likely your TPS. Transmission pressure solonoid. Which was common in 2000 LS2(v6). I really haven't read or heard of anyone with the solonoid problem after 01.

[sattech]

It IS most likely your "service wrench" light. and it HAS set a code. A P1811 has most likely been set and stored in your transmission control module. Bulletin #04-07-30-020 addresses this concern. In a nut shell it says that the pressure control solenoid- the thing that controls the line pressure which in turn controls the harshness of the shift- is sticking. This causes a harsh shift( of course). The repair is to replace the PC solenoid.

[ksion15]

Originally Posted by beensmoked

I really haven't read or heard of anyone with the solonoid problem after 01.

they didn't come out with the new solenoid until '04. so all l-series up until '05could experience this problem. i do them all the time.

[beensmoked]

i guess the tech lied to me then. He said it was rare to see it in my year. After they fixed it twice

[fsoltero]

Hello everyone,

The Saturn dealership finally got around to pulling the code from the transmission control module and it was a P1811. I spoke with the service manager and he referenced the same service bulletin as Satech #04-07-30-020. The manager requested my permission to have the technican troubleshoot the problem. He also informed me that I would be charged if this was not the problem. Go figure, the car is still under warranty and it wouldn't be behaving this was and setting off the wrench light if there wasn't a problem. I will let everyone know what the end result is.

[beensmoked]

your lucky then....TPS is an expensive job. It usualy cost around 900 because you have to drop the front end.

[SaturnManiac]

The service wrench light does store codes...you just can't read them with a universal code reader....you need a Tech II which the dealer has.

[fsoltero]

Success! The TPS is the problem and will be covered under the factory warranty. I'll have my baby back tomorrow. By the way, is there still a consensus out there regarding changing the tensioners when replacing the timing belt on the V6 engine? I am planning on changing out the timing belt in about 3 more months along with the plugs.

[Bigdaddy94sc2]

Originally Posted by beensmoked

your lucky then....TPS is an expensive job. It usualy cost around 900 because you have to drop the front end.

Unless you are doing it a much harder way, you dont have to drop the front end...