Another Crank No Start | OBD2 No Comm + Xmas Tree Inst Panel w/Bonus ‘It hasn’t run in months’

Greetings to everyone out there in TacomaWorld. I posted my intro in the New Member area, my first post ever to a forum.

TL/DR - 2014 Tacoma 4WD hasn’t been running since September 2022, but was cranked periodically up until a month ago. About to start troubleshooting again and need advice on the bare minimum work to 1.) Safely crank it again and 2.) Prep for in case the darn thing actually starts. Prep to drive would occur once I regain consciousness. Internet research provides many options; I'm just don't want to cause damage when the cranking begins again.

The rest of the story:

I have a 2014 Tacoma 4WD truck that will crank but it won't start. At least that was the original issue that occurred last year. Family illness and my own mystery ailments are the primary contributors to why it sat and why it isn’t at the repair shop. With the exception of cranking it every few weeks and pushing it about 20 feet to a different spot, it has sat unmoved since September of last year. Have learned the hard way how to properly maintain a car battery; there is a good and charged battery available for it.

Other parts of interest (in order of occurrence):

1.) Starting around a year ago, the blower motor would intermittently not work. The primary driver of this vehicle (not me) would wiggle the wires to get it to work. At some point, it stopped working altogether and the primary driver (not me) traced it to a melted plug, then cut the wire to try and get a replacement plug. Parts were ordered but never installed, and those wires are still cut. The kit is here somewhere if I can locate it, but prior to replacing the harness for it, need to look harder at the motor itself as it looks like the plug on it is warped.

2.) The night before the crank-no-start began, a thunderstorm dumped Biblical-level rain here, with lightning that struck the house twice, zapping a few things inside. The truck was in the front yard about 50ft from the strike locations. Probably coincidence, but worth mentioning.

3.) Scan tool will power on, but not communicate. Several were tried at the time and even recently. I honestly can’t recall if an OBD2 scanner was ever connected to the truck, so for all I know, maybe it never communicated to begin with.

4.) The crankshaft position sensor was replaced by the primary driver (not me), per suggestion from family member that is a mechanic (but not local). This was October of last year.


This below is more recent, within the past month:

5.) I’m NOT sure if this occurred to begin with, but today: the check engine light is not illuminating after turning the key on.

6.) I AM sure this didn’t occur before but is occurring today: Just about every light (except MIL/CEL) illuminates in the instrument panel when ignition is on.


Keeping it simple, here’s what I’ve tried, but will check again as a fresh start:

a. Ruled out immobilizer – the icon blinks, then goes off when key is in ignition.

b. Checked OBD2 port and the relevant pins for power. The pins fit snugly on the scanner. Haven’t checked for continuity, etc. yet.

c. Checked all fuses, but only with the light tester. I tested some of the relays by swapping with like kind available. Haven’t tested wiring for continuity or anything yet.

d. Removal of glove compartment and some of the dash panels (to check blower motor) uncovered an unnatural amount of dog hair and dirt. It’s apparent the previous owner ran a grooming salon inside the cab while simultaneously operating a landscaping and earth materials hauling business. Vacuumed out what I could; it’s taking everything in me not to hit it with an air compressor.

e. No rat nests and nothing appears chewed up so far. Will use borescope to keep checking.

f. Located ECU/ECM when scoping out blower motor. Only checked to ensure everything was plugged in snug to the ECM/ECU. Most electrical tape wrapped around the wires behind dash panel have lost its stickiness and is falling off, leaving the worst residue ever behind. No crimped, damaged, or burnt wires noticed outside of the 2 clipped blower motor wires. I need to research if the cut blower motor would affect any other areas.

g. Will check for loose wires/grounds as I re-check the above.


This is same question as in the TL/DR, which stems from it being a month since the last attempted crank and concerns with how long the truck has sat without running. Before I start troubleshooting again, what would be the bare minimum work to do to:

1.) Safely crank it again and

2.) Prep for in case the darn thing actually starts. Prep to drive would occur later once I regain consciousness.

Any guidance for the prep work (and anything else) would be much appreciated. I’ve been RTFM’ing and researching to gain familiarity, but I’m green sometimes when it comes to official terminology. Apologies in advance if I slaughter something with my descriptions.

Thanks in advance

 

Since you have no CEL on with the key on the first thing we need to check is powers and grounds at the PCM.
We can start at the engine room fuse box, check the EFI (20A) and EFI No 2 (10A) for power with the key on.

 

Thanks! As soon as it stops raining (around 1am per forecast), I'm on it!

 

I'll post up the relavent diagrams when I get a chance.

 

Here you go.

 

Tested both fuses with the key on, and both lit up on both sides. Photo attached of fuse box. Tried to get photo of light as I tested but that wasn't working out too well.

Also, thanks for the wiring info. It doesn't look so Greek like it did last year

 

Ok but you still have no CEL and no communication?

 

Correct. I just went out and confirmed that is still the case. I have tried other scanners; all cheap, all work on other cars, just not this truck. In the pics of panel lights, the green wheel base thing and the 4LO blink.

 

Ok and I'm asuming you don't have a scanner that is capable of scanning anything besides the PCM?

I think our next step is gona be checking powers, grounds & 5v ref at the PCM.

I'll get a list of pins to check when I have time, probably will be a few hours before I get to.

Did you check the fuses in the interior fuse box for power? Specifically IG1, IG1 No2, IGN, and ECU-B.

 

I tried all kinds of things, including the inside fuse box, but it has been awhile. This is a new path forward so I'll be trying anything needed and as many times required. I'll be checking the inside fuse box here shortly.

As for the scan tool, none have the capability to do things like transmission or ABS if that is what you mean. I think the cheap Bluetooth had engine or something on it, but I couldn't get past the connection issue.

Thanks again

 

I'm just trying to go after the easy stuff first, I'm going to start working on PCM power and ground pins here in a bit.

It's not a big deal at the moment I was just curious if anything else was online, first order of business is to get the PCM back online so the truck will run. We can address the other systems as needed.

 

Here you go, these should be checked with the PCM plugged in. A needle, small paperclip, or backprobe can be used, just be careful not to damage the connectors or short pins together.

Powers:
E14 Pin 21 (Beige)
E13 Pin 24 (Blue)
E13 Pin 22 (Black)
E13 Pin 23 (Black)
E11 Pin 23 (Light Green)

Grounds
E10 Pin 8 (Brown)
E13 Pin 12 (White/Black)
E11 Pin 12 (Brown)
E12 Pin 10 (White/Black)
E12 Pin 11 (White/Black)
E12 Pin 14 (White/Black)
E12 Pin 15 (White/Black)
E12 Pin 16 (White/Black)
E12 Pin 18 (White/Black)


5v Ref (should see 5v on these)

E11 Pin 13 (Red/White)
E9 Pin 15 (Blue)
E14 Pin 2 (Blue/White)
E14 Pin 4 (Red/White)
E9 Pin 16 (Blue/Yellow)

 

Thank you again - I've looked it all over and am ready, but will probably try this tomorrow with daylight. The bugs are bad tonight, and my headlamp only attracts them. It's more annoying than anything else. And it just started raining again, so yes, this will be tomorrow.

The links in your sig are indeed very helpful

 

Any luck?

 

Just now off work and about to head and test some of the PCM wiring per DM93's post. I'm slow at this stuff because I read...re-read, double and triple check everything (still learning). Will report back in a bit.

**Correction. NOW I'm heading out there.

 

Lesson learned, don't leave battery connected because you think you will be right back out to tinker again, but then it rains for 2 days.I guess leaving the battery connected for 2 days.
Battery showed 11.97, so it is on charger now. I re-famliarized myself with the wiring behind glove box, correlating it to the diagrams you provided (thanks again). My fat fingers aren't very efficient with that small space, especially trying to isolate any of the middle wires, so I removed some of that gooey-a$$ tape that wraps the clusters of wires and was falling off anyways. Much better.

If I'm OK to proceed with testing with the battery being low, let me know and I'll continue. Otherwise, I'm going follow some wires and look for some grounds while the battery charges. This stuff reallly isn't nearly as intimidating when you know what it is.

Attached are pics of what I'm looking at only as FYI.

Thanks again for helping.

 

Have you confirmed the OBD fuse is good? I had a similar issue years ago with the reader powering up but not communicating, it was this fuse.

 

11.97v isn't terrible (about 40% State of Charge), if you can keep the battery charger on it while your testing so it doesn't die on you you will be fine.

Yea I'm very familiar with that area, done lots of testing there in the process of helping people on here (and for my own curiosity). I can have the glovebox and trim out in about 30 secs

Looks like your cabin filter and a bolt are missing.

Good thought, I think that was checked already. In any case the PCM isn't online (no CEL) so plugging a scanner in isn't gona help us yet.

 

It (the battery) seems to be good now.

Hopefully I can get it all put back together. That's always the challenge for me lol

That was my doing when I was looking at the blower motor. I usually put the screws and bolts back in so they don't get lost. I had no idea cabin filters existed until a couple of years ago if you can imagine.

I checked it earlier with the light and with the multimeter (continuity) and it tested OK.

So I've been looking/researching/reading on testing this ECM wiring for the past several hours, because I thought I had it figured out, but didn't. For whatever reason, I got nervous standing there with multimeter in hand, visualizing the truck on fire from a faux-pas. Anyways, my "research" made it worse by polluting my head with "key on/off" "red lead/black lead where" "ground here or there" etc. I came back inside and cracked open a beer to start over. In the future, I'll be sticking to the service manual and the info that has been provided here. I feel like a moron.

To make sure I have this right, to test for example the power source at the ECM, it would be:

Multimeter on 20v DC
Battery connected
Key on
Red lead on needle on E13 Pin 22 (Black)
Black lead on needle on E11 Pin 12 (Brown)
Reading should be 11 to 14 V

If I'm supposed to the different power/ground/5v wires individually somehow, I'll probably need a point in the right direction on what to clip where...so the truck doesn't explode

Something I did notice - it looks like someone has been through the wiring for the ODB port on drivers side, and for a couple of wires on the ECM side. The tape job looks like something I did and not something from factory. I'll get some pics tomorrow.

Thanks again for the assistance.

 

When testing powers and grounds with a meter you always want your meter ground connected to a known good ground, circuit should be loaded (key on and whatever your testing plugged in and turned on), meter set to volts DC, and meter leads connected to the proper ports on the meter.

On power circuits you should see battery voltage (same voltage as measuring across the battery +/- 0.5v), on grounds you should see less than 0.1v.

For more info on proper circuit testing with a meter watch this excellent lesson by Paul Danner.
https://www.youtube.com/watch?v=w0PpLTnKKZg

What is the blue tape on the wires with stuff written on it?