Code P1780 intermittent no start issue?

Please let us know your progress and all that they will even test the module for you and all that.

You're welcome.

Hi,

Since there was an issue with a no-start condition, were you able to determine if it was an ignition or fuel-related issue?

What they are telling you, in my mind, is a way to protect themselves. But if you recall anything electrical that was causing issues, let me know and we can check some things.

Joe

All the Saturn L series I have seen that don't start when the gas gauge is inoperative was a bad body control module. I have seen tons of them. It's really common for them to go bad I lost count with all the ones I replaced all the years I worked at the Saturn dealer.

I have never tested for spark when I ran I to that situation I have also seen the engine control modules go bad but way far less common and when they did it was a tow in.I could never get them to start even to drive them into my shop.

What I have seen when the line pressure solenoid is going bad on those you get a hard shift and when you cycle the key the hard shift goes away. When the solenoid gets bad enough it will set a code p1811 basically transmission adaptives can't compensate for the shifting issue being caused by the failing line pressure actuator. When the transmission can't control the line pressure it will going into a fail safe mode. Which it shifts the transmission at full line pressure to help keep the clutches in the transmission from slipping and burning. Down side is if it's operated over too long of a period like that it will destroy the transmission.I have seen a ton of bad line pressure solenoids go bad a few of the other solenoids go bad. But those were seldom compared to the line pressure solenoid I don't see the transmission issue being related to the bcm at all.I have seen a bad bcm not let the car shift out of park and also cycle the transmission. Shifter release solenoid off and on over and over all by itself for no reason whatsoever.

The BCMs on those just fail for all different reasons and cause an array of different symptoms and codes to set. The most common symptoms is that no start and fuel gauge inoperative.

Did G7 say they found a problem with the bcn when they repaired it?I have never seen a short on one of those cars cause the bcm to fail and cause the fuel gauge to intermittently fail not start and have the fuel gauge inoperative.

Hi,

I noticed Saturntech hasn't contacted you for a couple of days. Have you been able to make any progress? I stepped back because he is excellent with Saturn vehicles.

Let us know.

Joe

Hi,

Yep, I understand. What we can try is this. First, I attached the connectors for the BCM pinout below. Next to the pin number, you will find what each wire is for.

Next, I attached the wiring schematic for the BCM. I had to cut it in half to make it readable for you.

Let's try it this way. Let me know the wires/connectors/pins in which you have an interest. I will try to determine what you should find at those wires.

I wish I had an easier answer. I understand what you are asking for, I've never seen one in a manual. There is always a focus on one or more specific circuits that are checked. They don't have a schematic covering all wires and their values. It would be a good idea, but that has never shown up in my manuals.

Let me know your thoughts. Let me know if you feel this will help.

Take care,

Joe

See pics below.