2011 V6 Crank No Start, No CEL, No OBDII Communication.

My friend's truck is a 2011 with a V6, auto, and extended cab. As it sits, everything seems to function except the CEL doesn't turn on when the key is turned to run, and the OBDII scanner says it can't connect. Assume I missed something though and throw out any pointers you can, please.

The problem began after the battery died, maybe from the key being left on, or the headlights. After putting it on the jump starter it would crank but not start. (I wasn't there.) The jump starter is some old craftsman 250A capable unit. It's not in the best condition but hasn't killed any other cars. During testing with the Charger on the 50A setting I did see 16v on one ECU pin, but 13ish on one of them next to it. Donno if that means anything.

So far I've done some basic voltage/continuity/ground checks comparing to FSM schematics. All the fuses have power when they should, and back probing the ECU seems to have battery voltage in all the places I think it should. Grounds are good. I haven't checked for 5V, or CAN, but I do have a good meter and a cheap ebay DSO scope.

I can print out pages from the Chilton's FSM at the library, and I grabbed about 10 today from EM15M1U, but the plug labels don't match what's in the truck. The ECU has sockets A through F but the FSM is G through J. The box attached to the left side doesn't have letters that I can see, and the wire colors don't seem to match, so I didn't touch it. But trying to match up wire colors on the ECU I do seem to be getting battery voltage when and where I should (turning key, hitting brake, etc.) just labeled differently.

Hopefully I'll be back tomorrow afternoon to do some more troubleshooting with anything you all can think of.

Thanks for reading!

 

Does it have an "Immobilizer?" When you put the key in and turn it to the on position, does the flashing red/orange car with the key icon near the clock stop flashing? If not, you have a fault somewhere with the immobilizer. I would confirm good key and then check the immobilizer antenna coil around the ignition key. If the flashing light turns off, not the immobilzer (or your truck may also not have an Immobilizer).

https://www.tacomaworld.com/threads...na-coil-was-the-problem.834171/#post-29886557

 

Hopefully it wasn't reverse polarity jump started, those old toaster/crackerbox battery chargers aren't too great to use on a modern vehicle because they tend to put out a ton of A/C ripple which isn't good for the electronics. Best to charge the battery out of the vehicle if using one of them.

There's 2 diagrams depending on the build date of the truck, I didn't look though them to see what if any differences there are though.
The ECM connectors are E9, E10, E11, E12, E13, & E14, on the wiring diagram they show up as letters E thru J which correspond to E9 thru E14

Need to verify powers, grounds, & 5v ref. If that's all good but we have no com and no CEL then the ECM is dead, if we're missing something we will need to investigate further.

Powers:

E11 Pin 23 (Light Green) (Battery) (ETCS Fuse)
E13 Pins 22 & 23 (Black) (EFI Relay Output) (EFI Fuse)
E13 Pin 24 (Blue) (Battery) (EFI Fuse)
E14 Pin 21 (Beige) (Ignition) (IGN Fuse)

Grounds:

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)
E13 Pin 12 (White/Black)


5v Ref (VC):

E9 Pin 15 (Blue)
E9 Pin 16 (Blue/Yellow)
E11 Pin 1 (Red/White)
E14 Pin 2 (Blue/White)
E14 Pin 4 (Red/White)

 

While an Immobilizer issue would cause a Crank-No-Start it wouldn't cause no CEL and no communication.

 

I took that as the CEL wasn't staying illuminated and no comms as not throwing any codes (so he didn't know where to start.) Its just so simple (if you have the immobilizer, not all do) to confirm that the light is off when the key is in the ignition before you start ripping things apart... It probably is 99.9% not the immobilizer but when all it takes is your eyes, why not check that first. The immbolizer antenna coil is pretty thin lightly soldered wire. I predict its going to become more and more of a Gen 2 "crank but won't start" source of troubles in the future.

 

Dm93 Thanks for those files, I should have printed those out too. He said it wasn’t reverse jumped, I’m leaning towards over voltage or dirty power. I’ll be at the truck in about an hour to test.

tenui when I get in the truck the immobilizer light under the radio is flashing (pretty sure it’s not solid) and when I put the key in it turns off. I don’t remember if there’s one in the cluster.

When I turn the key to run, normally the CEL should turn on for a few seconds then go off, correct? That never turns on.

 

There's only one Immobilizer light, that's normal behavior for it to flash with no key and go out when a valid key is inserted.

CEL should come on and stay on with the key on and engine not running, the fact that it isn't suggests the ECM is offline.

 

Truck is made in mexico date 3/11
Does the ECM generate the 5v?

12v is good, W/B grounds are good, all 5v measure 0.43v ref to ground. (Dash bar and E11 Pin 12 BR.)

E11 Pin 12 BR is measuring good to ground when the key is off, and 8ohm with key on (In Ohm and continuity beep test) and 0.008V ref to ground.

See pic of E11 Pin 1 is empty and W/R (white with red stripe) is in pin 6 measuring 0.44v

Thank you.

 

So everything is good except the 5v ref?

If so we need to unplug 5v sensors one at a time and see if it comes back.

Cam sensors, throttle body, APP sensor, and the EVAP Leak Detection Pump I know for sure are.

 

Ok I’ll be able to do that in about 30 mins.

I read a similar thread about unplugging sensors and I was able to reach a few last night but not the cam sensors. And I didn’t see a secondary air pump. I’ll remove the air box when I get back and pull cam sensor plugs too.

Note I was only confirming “not bad” by checking if the CEL comes back on with each sensor unplugged. I haven’t checked for 5v with sensors unplugged yet.

is it possible to unplug a bundle of sensors at the ECU to easily verify a bunch at once?

 

Everything I can reach is unplugged and only 0.5v
Evap pump is on the charcoal canister, right? And air injection should be on passenger side manifold if it had one? Also unplugged what I assume is oil pressure. What about coolant temp? I can’t reach driver side O2 plug. Am I missing anything?

 

I think that's everything, I'm not at my PC right now to look at diagrams but you can unplug the ECM and ohm check between the 5v pins and ground to make sure you have no shorts to ground.

 

Yeah, no shorts to ground on the ones you listed. I’m partially through just going down the list and testing all of them.

 

Certainly looks like a bad ECM if powers and grounds for sure check out.
At least they tend to be relatively inexpensive used for auto trucks, just need to match the part number on it.

 

Is it reasonable to bench test it or take the ECM to Toyota for them to test it? Or is the next step swapping it?

 

A used ECM is around $100, if your confident in your testing I'd just swap it.

 

Did you replace the battery or just charge the completely dead one and hope it was good? Once completely drained, you may as well bite the bullet and replace it because few batteries come back from the dead.

 

We’re calling around and autozone wants $300 with $30 core return. Dealership I think said $250 diag fee. We’re trying to find who they send them to. We’ll also keep looking for better prices.

Yeah I see a couple dead-dead batteries every winter. The battery was charged at the 50A setting for a few hours while I was testing. The owner mentions the charger wasn’t working for him on the lower current settings for some reason, but the 250A jump setting worked fine. I didn’t current test the 50A setting, but it was charging and not heating up the battery. I really need to buy a clamp meter. It cranks really well, and seems to hold a charge overnight about 12.6v

 

I really should test the charger, and maybe have him replace it.

I’m assuming it’s CC-CV because while I was testing I was measuring about 13.8v except that one random pin at 16v. I haven’t re-tested looking for that 16v.

 

Grab you a used one $100 or less, I don't trust reman ECMs we almost always have issues with them.
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