2002 Suburban Passlock problem

my knowledge of automotive electrical wiring is currently limited to repairing rat chewed wires.

There is this whole other world of schematics, connectors, wires, diagrams etc that I'm just now learning.

Thanks for the advice.
JW

rained all day...
I think Aspen500 sent me his wonky weather.
Still raining.
Another 3 hours and 'they' say it will be done for 48 hours.

JW

Sorry..................

Weather folks were wrong.
Been two more days of rain and a 40 degree drop in temps.
What is with this weather pattern? High yesterday was in the 40's. Today we might get to 50 and its been raining off and on for 36 hours. Bleh!
Then in two more days its supposed to be 82 to 86.
Driving 34 miles round trip to stomp in the mud and rut up the field feeding cattle is NOT fun.

Government boys did get the 6 1/2 acres of easement planted with baby blue stem and millet.

Friend is coming over to drop off some wire I can use for the Suburban. Nobody has 22g wire anywhere in my closest town or at the farm co-op. But rancher down the road has some in his work truck. Just need about a foot and I can get to the next step.

Said he'd drop some off today. Once the rain quits and I get the wire, I'll go rewire the fuel injector.

So basically, no progress.

JW

HOUSTON --- WE HAVE TAKEOFF!!!!

It took another marathon of 2 + hours; but I found the problem.
Dead Short.
Grounding wire.
Caused the cluster to have hallucinations and display passlock.

What was really happening was:
1. Dead short, one of two grounding wires was broken in engine compartment

2. Couldn't see the short/wire break due to location at back of engine in the 4 inches between the engine and the firewall.

3. No ground meant the PCM (brains - power control module) wasn't happy. So it refused to talk to the BCM (body control module).

4. BCM, even with the bypass installed, seemed like it was good; however, it was only good on one way of communication/ not on return communication.

5. Splice1 connector under the dash had one wire that wouldn't give a good ohm reading. The color of the wire had absolutely nothing to do with the problem. Why I fixated on that dang green wire is beyond me.

6. Two injector wires that the rat chewed through also contributed to the problem. One was power and the other was communication. Couldn't see that without fondling the wires under the fuel rail. I did learn how to take apart a fuel injector and repair it for less cost than buying new.

7. Unplugging the radio did nothing to help target the problem; but did let me clean more dirt and gunk from in the dash.

8. Uncovering the cowling covering the keylock cylinder and sensor did nothing to help target the problem; however it did let me clean the contacts so the hall sensor effect could be sensed easily. And I learned how to remove the cover and how to remove the key cylinder.

9. I did learn how to isolate problems by using continuity testing against the fuses in the power distribution box under the hood. Didn't tell me what the problem was. Did tell me what the problem WASN'T.

10. One of the most important things I did was not give up and I started over a dozen times or more. Every time I thought I had defined the problem, I realized I was defining the symptoms. I completely get why a fancy scanner would have nailed this sooner.

I'm thankful I didn't just throw parts at this problem.
It just felt like it was the PCM from the get go.

I did get an extra bypass module out of the process and I now have much greater confidence in my abilities with vehicles.

Although to be honest, I found this by Brute Force. I got up really irritated that I couldn't figure out this problem after 22 days. So early one morning this week (Friday), I got my aluminum bench over to the engine compartment and proceeded to unplug every sensor and remove the wiring harness.

About half-way through the process, I found the broken wire at the back of the engine.

Happy dance ensued!

JW

Sometimes the only way to figure out the problem is to round and round in circles eliminating what is not the problem until you finally find it. Good on you for sticking with it. Far to many people(some mechanics included) just keep trying to throw more parts at a problem.

So now it runs and drives? Time to get rid of it! Seriously, while you can get money for it.

I swear to God, if I had the fortune to be living in Texas like you I wouldn't own anything newer than 1995 - right before the transmissions went full computer control and a few years prior still before body control modules and theft prevention systems became commonplace. The mid 90's was the sweet spot for Chrysler and late 80's for Ford as far as electronics complexity vs ease of fixing became lopsided.

Get yourself a late model Ram Charger and dump that GM crap. It sounds like you're really good with this stuff. There isn't anything you couldn't fix on an early 90's Ram Charger.

I had a dodge dakota, long bed, that I bought brand new the last year they had carbureted engines. Sold it 11 years later when I bought my chrysler concorde.
Seemed like a good idea at the time but, I'm thinking I should have kept it.

JW

Justwondering said:

I had a dodge dakota, long bed, that I bought brand new the last year they had carbureted engines. Sold it 11 years later when I bought my chrysler concorde.
Seemed like a good idea at the time but, I'm thinking I should have kept it.

JW

Click to expand...

Don't by shy about fuel injection. It didn't get messy until after 95 in Dodge land. The Mag motors prior to that had multiport fuel injection and the entire ECU and harness was simple. Even the speedometer gauge was still mechanical at that point. If you got that GM POS running, then that would be a cakewalk for you!

Good deal! In many cases I run into, the only way to find what IS the fault, is to eliminate everything that ISN'T the fault. When it comes to modules, there is no real way to test them in the field so you eliminate every other possibility until the only thing left is a module. Even then, there's always doubt until the new module is in and programmed to the vehicle and the problem is fixed. Before that, I end up with "did I miss something" in the back of my mind, especially since once the module is installed and programmed, there's no returns. Actually, once the seal on the box is broken, it's yours.

We have the same issue with controllers in industrial equipment. You opened it, you bought it, so you better be sure that was what the problem was.

Yep, you want to make darn sure every other possibility has been eliminated and then, double check your work before condemning a module. Last thing you want the shop to be stuck with is a $800+ module, plus the $40-$100 for the programming software and all the screwing around it takes to code the module to the vehicle that you can't return. Heaven forbid it's certain makes or models built after about 2016 or so, and it requires security access to program the keys before the engine will start. Then your screwed and it has to go to the dealer for programming. Or,,,,,you have to be a licensed locksmith to be able to get the access code to do the programming. It sucks.

Next up is the 1997 Ford F350 Diesel Dually.
Figured while we are stuck at home dealing with the virus thing, I can get all the vehicles running again.
I know its problem ... orange diesel and no fuel getting to the fuel bowl.

The fun will be removing the tank or jacking up the bed.
But that's for another thread.

JW

It is almost a conspiracy with the manufactures when it comes to modules. I guess they are taking after printer ink cartridges – where (sometimes) it is cheaper to purchase a new printer than to replace the ink cartridges. Having to burn the VIN into the module be is usable – makes it not usable for any other vehicle – without using expensive equipment (in other cases) – so a quick part swap with a “known good part” is pretty much impossible now days.

When I was a tech working on the computer system on FMJ vehicles, there was no way to communicate with the computer. Chrysler's answer was a big box to test each sensor with – which was cumbersome to work with. The faster method was to have a box of “known good parts” and start swapping parts out. I could do this – in many cases, faster than retrieving my DVOM (Digital Volt Ohm Meter) from my neighboring tech who swiped it testing his assigned car, and testing. You can't do that on cars built around '95 (or so) or newer any longer.

Getting back to your F350. Most trucks now days, it is easier to access the in-tank fuel pump by either removing the bed, or removing bolts from drivers side/loosening the bolts on passenger side and tilting the bed up (at an angle) to access the fuel pump.
Trying to drop a 40-gallon fuel tank with fuel in it, without a lift and a transmission jack is not for the faint of heart (about 350ish pounds).
BudW

The main reason modules need programmed to the vehicle is, when you get the new one, it's "generic". They need programmed to the VIN and as-built data because there are so many variations in equipment and option level, as well as different models. The same PCM (or any number of the other 8 billion modules in a newer car) might fit 5 different models with possibly 10 different engines for example. You buy the hardware and then program the software afterwards (basically). Problem with the software is it's all licensed, hence the cost of buying it to install in the module.

I remember the days of test each component individually with a DVOM until you find the fault. About all you got on Ford's (starting with EEC-1, 2 and 3 was a 2 digit trouble code to give you a starting point. Early EEC-4 wasn't a whole lot better but then they went to 3 digit codes and eventually added PID data you could see on the scanners of the day. Then EEC-5 came out (OBD-II) and everything got A LOT easier to diagnose. The latest systems using the latest scanners are complicated but,,,,,,,,,you can see any piece of data you want, in real time and narrowing in on the fault causing the problem isn't all that bad. A scanner still won't take the place of manual testing with the good old DVOM but without it, anything electrical or electronic on the modern automobile would be IMPOSSIBLE to diagnose. Problem is a GOOD scanner pushes $10,000 or more PLUS the $200-$800 per month for updates and $100/month for the online database access for other functions, so having one at home probably won't be common, lol.