Chevy & GMC Vans

03 astro LT 2WD
No history of running or starting issues in all its 164K miles

Prior problems that could be related:
No rear heat. Fan blows but no heat
Intermittent front fan and defrost. Sometimes it works but most of the time it doesn't.
Door locks try to lock while driving at random times.
Intermittent check engine light/code for "Low coolant temp"

As I said. Never an issue starting or running before except for two months ago it lost power due to a loose battery neg cable.
I've sense cleaned all pos and neg terminals I could get to.

Problem started last week. It sat in our drive for two days without driving.
Went out to start it and it would crack and crank but no start. Heard fuel prime and smelled fuel when I pressed gas pedal.
Tried to start it the next day. No joy

Sat for 3 more days and went out to try it today and it fired up instantly and ran fine.
Full voltage during the no start and after it finally started.

I drove it strait to The parts store and had them pull the codes

It still shows the low coolant temp code as well as:
Class two data link malfunc. - U1000
No DTC definition found - U1041
Theft deterrent - P1626

From what YouTube tells me the theft deterrent is the likely cause of the no start.
But I don't know how to fix that and have no idea what the other two code are and if/how they are related to the theft det. Or the no start.

Any help tracking this down will be much appreciated because sense it is now an intermittent problem I don't trust it to drive until I can better fix the problem.

When it wouldn't start had it been wet or raining just before?

How much coolant is in your system now?

Can't help with the theft deterrent code, did not have that on my old 95...the fact it wouldn't start half the time was deterrent enough,

I'm fighting the P1626 code, myself.

Lacking the time, I took my 03 to a garage I trust to get it figured out. They replaced the PassLock sensor in the ignition, it started fine for a week, then throws the code again. It's back at the garage now, waiting for the next diagnosis. I fear it could be the body control module dying and hope it is only a bad connection, somewhere.

The Class 2 DL malfunction makes me wonder if you're dealing with a failing connection, also. If the system fails to get the permission signal from the ignition to the BCM, the code will be set and about 30 needs to expire before you can get it started again. A failing connection, somewhere in the DL could cause it to happen. The other two codes leaf me to thinking the same thing.

I'm no pro so don't take my opinions as gospel. I'm just the grasshopper, following Master Po on these boards.

Good luck and let us know what your solutions are!

I believe your heating issues is caused by one or more leaks in the vacuum system. Which also might cause running and starting issues. Check all the vacuum tubes around the engine. The no start might come from a bad distributor cap/rotor. I just had that.
No clue about the theft thing.

Yes. It was raining for a couple days. After it dried out is when it started again.


I'd say there is a vac leak but that wouldn't cause the fan not to blow when the fan does work I have pretty good heat and AC.

I've yet to get time to pull the dog house off and check all the wires I can get to. I suspect and hope its just chafed wires or bad connections.

So far no more issues yet sense the temps have dropped below freezing the heat/fan has stopped working again. Seems to work more often when its above 44*.

It hasn't rained again but hasn't failed to start again.

So far no more issues. Its been very cold and raining and no more failures other than the heater fan stopped working again. And currently no codes are showing. Very odd sense I haven't touched anything sense it failed to start.

Now is the time to start hitting things with a little bit of water to see if you can find your problem.

Bad gas?
Rain, and moisture?
Loose wires?

Good luck

AP

Still no further issues but still no heater fan. Work has been hell for a while and I haven't had a chance to get under the cowling to poke around at wires and vacume hoses.