Hey everybody. I have a few questions to ask after I’ve been pooling for hours on this and several sites checking out all of the posts. Everything was running great, no problems with the car. There is a car show coming up in about a week and I decided to detail under the hood. I covered the opti, all electrical, the alternator, etc. washed, scrubbed, and rinsed. After this I started the car to move it back in the garage and it started and ran for about 5 seconds and then died out. I attempted to restart the car and it wouldn’t restart. I’ve had this happen before after a rainstorm or after a bad mechanic shop did a sloppy coolant change. Anyways, I usually just let the car sit and it dries out and runs fine no problem. This has only happened to me twice. I’ve let it sit for three 24 hour days and collect a lot of sunlight to dry things out. Today is the third day; I went out to start it and still just turns but won’t start. So, I hooked the scanner up to it and pulled all the codes and they were as follows and in this order 1) P0372 2) P1371 3) P0336 4) P0372 5) P1371. I then cleared the codes and kept the scanner on while cranking and the only code is P1371 and this one is flashing pending. SO, having said that, I know what the codes are and what they mean, I have Autotap software, a scanner, the GM service manuals, all the yada yada stuff. The GM manuals say the computer sets the code after two unsuccessful rotations of not detecting a low resolution impulse. This would lead me to believe opti even though in the past drying out has worked; the third and final time may have been “the straw that broke the camel’s back”. Making a long story short, my question is: based on everyone’s past experiences here and the codes and symptoms I have listed, do you think the problem is in the coil / ICM / both, harness, or the opti? Also, where is everyone getting their Opti’s these days online for a decent price? Any good ideas for drying out the opti via the vent hoses? Thanks in advance for your help. I really appreciate any help that anyone else can give.

 

Sounds like the opti alright but start by checking the connectors and pigtail off the main harness for a wet connector or corrosion (three possible connections). That one down into the opti is hard to inspect, but it can be a troublemaker. Not sure if you can successfully blow it out through the vent lines, and dont go squirting anything in there, either.

 

P1371 is for the signal from the Opti optical sensor. Its either the sensor, one of the two sections to the wiring harness, the PCM or the PCM connector.