No start

[99WhiteC5Coupe]

I checked the run/start relay via multimeter. Shows it’s operating normal. I’m seriously at a loss.

Have you cleaned the battery cable connectors with a battery brush tool and switched to a known good battery?

 

[MTX65]

Second what @99WhiteC5Coupe said.


You can not diagnose anything electrical until you know it has and is getting the correct voltage.
Start with your battery Go get it tested properly, any Auto parts stores do it for free.

Once you know that you have a good battery
do a Voltage Drop Test to make sure all your connections and cables are good.

Only then can you start to diagnose. Unless you like running in circles

Had the battery checked (voltage and load tested) and it all came back normal. I’ll have to look into drop testing.

 

[MTX65]

Have you cleaned the battery cable connectors with a battery brush tool and switched to a known good battery?

Connectors and posts were cleaned thoroughly. Haven’t switched to a known good battery but I did have it tested and it came back fine. Still a chance that a new battery could do the trick?

 

[Yupster Dog]

Check ground connections.
A lifted ground can cause many systems to mess up at the same time like that.

 

[MTX65]

Check ground connections.
A lifted ground can cause many systems to mess up at the same time like that.

I checked all the grounds in the engine compartment. Haven’t checked the ones in the cab yet. Got a new battery. The other day the truck would start right up if I skipped the on position. Just put the key in and turn all the way and it would crank. While running I would get various random codes or no codes at all. (Abs module codes, IC codes, RCM codes) but they were never consistent and would change. Fast forward to today I put a new battery in it and made another attempt. Truck wouldn’t start. I initially tried starting it as usual (on position let the dash cycle and then start) unsuccessfully, then tried to trick it by skipping the on position again and even that didn’t work this time. (I’m assuming because by making the first attempt the truck is storing whatever information it needs to keep it from starting after shutting off.)

 

[Yupster Dog]

(I’m assuming because

Found the problem. you are running in circles instead of actual diagnostics to rule out and move forward.

Nobody can help you from across the internet on your assumptions.

Start over with a "Voltage Drop Test" of all the battery cables (positive and negative)
Check the ground coming off the PCM And other grounds under dash.

You need to finish a diagnostic to rule it out.

 

[BigOleFordFan]

Well it seems as though I spoke too soon about my issue being resolved, because it began all over again on 5/9... so back to the dealer again on Monday, and will wait to see what they say this time...

And yes, I have tried all the suggestions already mentioned in this thread, so I'm back at square 1 as they say...

I am instructing the dealer to just FIX it, either by repairing/replacing/disabling/bypassing or removing whatever components that will correct the issues & give me a fully functional vehicle that I don't have to constantly wonder whether it's gonna start or not when I need to go somewhere....

Thankfully, I have other vehicles to drive in the meantime, but I love my Expy & wanna get it back on the road full time, like, now

 

[BigOleFordFan]

Well, now the dealer says they found 3 additional fried relays, and stated that those 3 & the 1st one they found are directly in the circuit path and part of the PATS wiring, so that when any of them fail, it interrupts the power flow to the PCM, which in turn kills the start up sequence and then triggers the flashing padlock... And that the flashing padlock is the only way for the system to indicate a fault anywhere in that circuit, and that it is not actually an issue with the anti-theft system itself...

Going to pick it up later today, with fingers crossed

They also stated that the next phase would be to start pulling/checking/replacing wiring harnesses and the PCM itself, which will require ALOT of labor & additional diagnostics....so in other words: mucho deniro

 

[MTX65]

Well, now the dealer says they found 3 additional fried relays, and stated that those 3 & the 1st one they found are directly in the circuit path and part of the PATS wiring, so that when any of them fail, it interrupts the power flow to the PCM, which in turn kills the start up sequence and then triggers the flashing padlock... And that the flashing padlock is the only way for the system to indicate a fault anywhere in that circuit, and that it is not actually an issue with the anti-theft system itself...

Going to pick it up later today, with fingers crossed

They also stated that the next phase would be to start pulling/checking/replacing wiring harnesses and the PCM itself, which will require ALOT of labor & additional diagnostics....so in other words: mucho deniro

Oof fingers crossed for you. I finally took mine to a dealership after trying myself and even hiring a mobile mechanic/electrician service who wouldn’t even charge me because he couldn’t find any problems. Dealership said it had a bad abs module. “At the time no other codes” but the module was on an all stop no sales so they couldn’t get one. I found a new one from a dealership 30 minutes away, went and got it and installed it today. Now waiting for them to program it. Asked them about it causing the pats light and a no start and got a beat around the bush non answer followed by a “we will see after we program it now” when they called they told be essentially “abs module, can’t order it, come get it by the end of the week. Miraculously I found 4 new ones within an hour AT FORD DEALERSHIPS. They slipped up today admitting there were other codes for the CAN BUS in addition to the abs module while I was there. Sounds like they were just trying to get rid of it to me. The Tech told me he got it started by wiggling the key in the ignition (I wonder for how long because I read that could occur with a bad ignition cylinder)