Live data p0172 p0175

[Jhkj04]

New BCM and It did work no programing. Still getting a draw, I did find the starter repay or switch wire was crunchy so replaced to the first harness plug under the battery. So still a draw and still seeing odd voltage at the coils when running rich. Also under the still searching category I’m noticing the shifter button isnt releasing smoothly. What’s the best way to search for this possible grounded pos? Even with the bcm and PCM unplugged and all the harness connectors around the bcm unhooked I’m seeing a draw can the fusable link where I see 2 reds into one and 2 pinks into 1 cause a draw? And anyway to test a PCm before I spend $200 for a new one?

 

[DadOSix]

New BCM and It did work no programing. Still getting a draw, I did find the starter repay or switch wire was crunchy so replaced to the first harness plug under the battery. So still a draw and still seeing odd voltage at the coils when running rich. Also under the still searching category I’m noticing the shifter button isnt releasing smoothly. What’s the best way to search for this possible grounded pos? Even with the bcm and PCM unplugged and all the harness connectors around the bcm unhooked I’m seeing a draw can the fusable link where I see 2 reds into one and 2 pinks into 1 cause a draw? And anyway to test a PCm before I spend $200 for a new one?

so - let me ask, because I lost track of where all you have tested -

How much draw and how are you measuring that ?

With your BCM and PCM unplugged, and still seeing a draw, why are we thinking of spending $200 if they are not affecting the draw / problem?

When hooked up to measure the draw, I would work systematically thru the power distribution box and the fuses, both underhood and in the cabin. Pulling 1 at a time and going back to check the draw. When I measure draw, I put a meter in line with the battery by removing a cable, and putting the meter on amps, and 1 end to the battery and other end to the cable. That way I know I am measuring a draw. There is an alternate way of measuring a voltage drop or differential across each fuse. It works, but I am more akin to doing it with the amp meter. Most draws, btw , are too slight to measure accurately with an amp clamp.

i hope this helps ya!

 

[Ksat]

Not sure if you're thinking this way, but it's unlikely the PCM/BCM is the source of your fuel trim problem. I'm also not sure why you're focused on this suspected amp draw to begin with. Is your battery going dead?

Coil (primary and secondary) voltage can only be properly measured with a scope. If you're using a regular meter, that is not going to work. If you have a scope, post a pic of V waveform here. If you have an amp probe, post a pic of the coil's primary amp draw, too.

 

[Jhkj04]

Did t have a scope just a volt meter. Felt it was a good start to clear up the draw first and that if I found a positive grounded out it might be tripping up the pcm and coil voltage. I’ll start over and test on amps with numbers.
Battery was not dead.

 

[Jhkj04]

Guess first , is my meter setup correctly? This reading I set the battery out and have cables so I could see the harness. Pcm and bcm all bcm harness connectors disconnected for awhile. Aftermarket Radio amps unhooked, radio harness unplugged.

 

[DadOSix]

Guess first , is my meter setup correctly? This reading I set the battery out and have cables so I could see the harness. Pcm and bcm all bcm harness connectors disconnected for awhile. Aftermarket Radio amps unhooked, radio harness unplugged.

looks ok so far - you took the battery out, so are we hooked to battery thru jumper cables or do you have a charger hooked in for power?

- your meter is reading negative, 14.5 ma - not a huge draw. I would start pulling fuses. 1 out - read, 1 in and 2 out read. etc. This should help ya find the draw. Tedious, i know, but you at least are working in a logical fashion.

a draw like this suggests a lamp burning, maybe a door lock sensor if you have power locks, maybe the back glass latch / switch.

 

[Jhkj04]

This is no charger just batt and cables. After that pic I unplugged the pos batt and came back an hour later to this.

 

[Neal]

This is no charger just batt and cables. After that pic I unplugged the pos batt and came back an hour later to this.

Your meter is not set right --your are switched to milli volts--should be set to milli amps.
But if the load is over 200 mills the fuse in meter will blow.

 

[Jhkj04]

Dang. I’ll start over. And check the hatch’s and interior lights while I’m at it.

 

[DadOSix]

Your meter is not set right --your are switched to milli volts--should be set to milli amps.
But if the load is over 200 mills the fuse in meter will blow.

Good eyes Neal! Not enough coffee for me this am!

 

[Jhkj04]

Ok 200 mil I’m seeing 000 now with almost everything plugged back in. Bcm and its fuse panel, pcm, alternator, starter, radio all the amps and speaker leads batt pos same meter between the neg. Is this possible? Lol

 

[Jhkj04]

Batteries back in almost everything connected and still 000 amps. Found the rear cargo light bulb shorted out and I’m seeing the door locks not functioning. Thought maybe it was the new bcm so swapped back to the old and they are worse. No noise at all. With the new bcm or salvage bcm they make noise but don’t function the locks. Pulling door panels next to test and see what’s up.
I’ve not found a scope to test the incoming coil voltage yet.

 

[Jhkj04]

She all back together. Ended up swapping the bcm again as it was ordered before I ran to the pick and pull and it has a closer build date or software match to my original unit. Somehow I ended up with a bonus and the truck unlocks all the doors when you park it and it never did that before. Hated it only unlocking the driver door now it’s all doors and hatch. Not seeing a draw currently but still seeing the codes and rich condition. Starts, runs, drives just allot of -32 short term fuel trim.
Odd thing I saw.
Door locks- all 4 wires to the actuator show ground until pushing the button and one switches to positive.
Test- no scope yet just voltmeter seeing random voltage at the coils. What’s a cheap scope I can buy?
Next- can I test the PCM? It wouldn’t surprise me with the pos starter cable making contact to the frame it be bad. It sustained a drawn out moment of contact.

 

[Ksat]

I use an Owon VDS1022I USB o'scope. Runs about $100. Download the software from github instead of the manufacturer, as it's improved (HScope apparently works with it, too, if you have an Android device). For something more portable, I've personally been eyeing the Zeeweii/SigPeak DSO2512G scope. Not as functional as the Owon, but it's cheaper at about $75 on Aliexpress.

You'll probably need to invest in other accessories besides the scope to get the most use out of it, such as longer test leads for automotive use, wire piercing and back probes, an amp clamp, an attenuator, etc.

 

[Jhkj04]

And this guy can tell me more accurately what I’m see from the ecm to the coil?

 

[Jhkj04]

Would this tc2 work? Seams to be the one I can get the fastest and in the price range of 50-150

 

[Ksat]

Fnirsis are utter garbage. Chinese scopes don't (collectively) have a good rep to begin with, but Fnirsis and their numerous re-brands are at the very bottom of that pile. Their prices are attractive (especially the tablets they sell), but they are little more than toys and have a list of problems a mile high list. Most YouTube reviews worth their salt have said their scopes are highly unreliable and largely unusable. That Fnirsi you posted doesn't look like much of a deal, anyway, especially since it seems to be only 1 channel.

Some other (handheld) scopes that have decent reviews that are worthy of mention and are all 2 channel are the Owon HDS242, Hantek 2C42 and the Hanmatek HO52. The latter which appears to be made by Owon, as well. Those are all about $100+ each.

In addition to the 2 channel Zeeweii/SigPeak I mentioned in my previous post, the brand also makes a 1 channel scope (DSO1511E), which according to reviews I've seen seems pretty competent. You lose out on not having the extra channel, but if you're on a budget it might be the ticket. Price seems to be around $60,

To answer your question, yes, any scope I mentioned should be able to catch the coil's primary voltage however you will need to invest in an appropriately sized attenuator to go along with it so that you don't exceed the scope's max voltage rating and blow it up.

There are a lot of good youtube vids that explain the process in more detail, which you may want to check out before you go hooking things up.

 

[Ksat]

Just to backtrack a bit, if you're looking to basically just confirm that a given coil is receiving a signal from the PCM, you can do a very basic test for that by just using a low amp draw LED test light/logic probe. Unplug the electrical plug going to the coil, probe the appropriate pin on it and crank the engine, If the light blinks, you know the PCM is sending something to it. Using a oscilloscope would give a more detailed analysis of what's going on there, but if you don't need to know that, a test light would work fine.

 

[DadOSix]

Just to backtrack a bit, if you're looking to basically just confirm that a given coil is receiving a signal from the PCM, you can do a very basic test for that by just using a low amp draw LED test light/logic probe. Unplug the electrical plug going to the coil, probe the appropriate pin on it and crank the engine, If the light blinks, you know the PCM is sending something to it. Using a oscilloscope would give a more detailed analysis of what's going on there, but if you don't need to know that, a test light would work fine.

Just to add. You can use a 'noid' kit. I tried one and it worked kinda. Flashed but very quick and dim. Never would have seen in daylight under the hood.

 

[Jhkj04]

Went with the test light option. 2 options. Pulled the coil plug and key on asd relay out I have nothing on 1 or 3 left and right and I have faint ground middle. If I activate pin 87 on the asd I get that middle coil pin to switch from faint ground to 12 v. Similar odd thing at the iac plug. It’s 2 pins the right has good ground the left has faint ground and when activating pin 87 of the asd relay it flips from faint ground to pos 12 v. Should t these at the plugs be nothing not faint ground but zero Anything? Just tested all 3 pins at a coil plug. Outside 2 on test lights middle a volt meter. Middle shows ground and 12 v the other two zero key on. Cranked it and nothing on the outside 2 test lights the middle looses ground And then jumps around on voltage as cranking. Wish I could load video.