Hello, been a while since I've had issues I couldn't handle.

2012 1500 5.7
Cranks, but no start. It can crank forever, but no start.
-P0685
-P0688

I've done a bit of diagnosing so far;
-Fuel pump runs with key on, and while cranking
-swapping ASD relay with HVAC relay, no change
-gone through fuse box for any blown fuses, just used a flash light and my eyes and none appear to be blown
-charger on battery in vehicle (2017 battery, still good since it can crank forever)
-fuel is definitely at 3/4 tank

I believe my next step is to hardwire jump the ASD pins and try, which I will tomorrow. Anything else that the crowd would recommend I try? I've been reading through many other forums and a big go-to is the OBD-II tool to cycle items, but I only have a basic bluetooth reader and torque pro. Trying to avoid the dealer as it would be a $200 tow, then $120/hr, and I'm on a tight budget right now.

 

As you're probably aware, both of those diagnostic codes relate to the Auto Shutdown Relay control circuit. Since you've swapped the relay with a relay that is presumably working, the next step would be to start tracing the signals to the relay to determine if the relay is getting switched power and if the relay coil is getting good power and trigger. Do you have a wiring diagram for your truck and the ASD circuit in particular? Are you familiar with how a relay works to be able to test the signals to the relay?

-Rod

 

Yes, I understand it all lies there. I do not have any wiring diagrams for this truck unfortunately, I'll search and see if I can locate one tonight.

Essentially, with key on the 86 should be powered, and energize the coil powering 30, which from there powers the PCM?

 

Pin 30 should be hot at all times, that's the main power feed TO the relay. 87 should be output to the systems the ASD relay feeds. (injectors, and coils, plus some others.) I can't find a diagram just at the moment..... I *think* 86 will have power with ignition on, and the PCM grounds pin 85 to control the relay. To bypass the relay, jump pin 30 to pin 87.

 

Tried the fuel pump relay bypass (even though the pump turned on with the key before) and made no difference. It's a blizzard outside and I need my truck. Guess I'm boned. I bet this will be an easy $1000 dealer visit, again.

 

Fuel pump relay, and ASD relay are two separate issues. Are you getting power to the coils/injectors?

 

I haven't been able to check, have a job in my shop waiting on parts so I can't get it inside, then ontop of that today we get a blizzard with 10" of snow and -20°c windchill... just the absolute perfect nightmare.

Hopefully if it clears up tomorrow I can take a proper look. Too much work/stress and not enough home time is just driving my brain to the easiest conclusion, I don't know why I went down the fuel pump path after I already figured out my pump was running.

 

You need to sit back, relax, have a cup of your favorite beverage, have a smoke, if you indulge in that sort of thing, get warm, and watch the pretty snowstorm from the comfort of your living room. The project in the garage will wait for you, and your truck will still be sitting right where you left it. Not a damn thing you can do about any of it right now, so, don't even worry about. Spend some quality time with your wife/kids/whathaveyou. The world won't end if things don't happen RIGHT NOW!!!!

And yeah, you expect your truck to break down only when its nice weather???? Now there is a dream that ain't gonna come true.

 

Haha I wish it was that easy. My other truck is trapped behind this one, blocking the garage, and my winter beater car feels like its about to blow a wheel bearing... total crapshoot. Lol.

 

Yeah, that looks like REALLY good weather to STAY IN THE HOUSE!

Got 4 wheel drive? Then you ain't trapped, just go around. I was absolutely amazed at how much snow my 96 2500 would thru with A/T tires, and open diffs. I went to pick up a snowblower for my tractor, but, the blower is in the guys back 40, and there was 2 plus feet of snow on the ground. My truck drove back there like it was open ground. Didn't even think about getting stuck. I was impressed.

Besides, playin' outside in that is just not a good idea...... (unless you are getting paid REALLY well for it.......)