2014 4500 series 6.0 wont crank code p1682

THERE ARE 2 KINDS OF DTC.
ONE IS STORED IN MEMORY ,HISTORY
THE OTHER, IS LIVE AN FAILING NOW, IN REAL TIME.
seems your car battery is bad,. or its lugs loose or rusty?
p1682 (means starter failed to start the engine)
YOU DO KNOW ,RIGHT. BATTERIES CAN BE
GOOD
BAD (DEAD)
WEAK
OR INTERMITTENT.

9 YEAR OLD BATTERIES ARE MOSTLY NO GOOD.
THAT OLD.
MY LIFE TIME RECORD 1964 TO NOW IS 10 YEAR.
ONLY ON 1 BATTERY EVER.

There are 6 causes of no crank,
or 7 if IMMO lamp glows wrong killing starter dead on purpose.
6 tests to find it using $15 volt meter, easy.
free tests are stated above, lugs loose
check all fuses. oops. 20 cent fuse blown.
crank in park and then try neutral
hot wire starter motor , keys in pocket , safely
it will not start like that but the test shows 2 things are good
battery and starer both.
and then meter tests to find it ask.

https://www.way.com/blog/p1682-code-meaning-causes-symptoms-and-fixes/
https://www.obd-codes.com/p0685
https://www.obd-codes.com/p0686

P1682 Chevrolet Description There are 2 ignition 1 voltage circuits supplied to the Engine Control Module (ECM). The first ignition circuit is provided by the powertrain relay, through a fuse. This ignition 1 voltage circuit supplies power to all the internal ECM circuits associated with the throttle actuator control (TAC) operation. The second ignition 1 voltage circuit is supplied by the run/crank relay through a fuse, and is used to power the remaining internal ECM circuits. If the ECM detects a voltage difference between the 2 ignition 1 voltage circuits, DTC P1682 will set.

Read more: https://www.autocodes.com/p1682_chevrolet.html

P1682 Chevrolet - Ignition 1 Switch Circuit 2

Possible causes
- Faulty ignition switch
- Ignition Switch harness is open or shorted
- Ignition Switch circuit poor electrical connection
- Faulty Engine Control Module (ECM)
What does this mean? What does this mean?
When is the code detected?
The ECM has detected a voltage deifference between two circuits
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Possible no crank or start
P1682 Chevrolet Description

There are 2 ignition 1 voltage circuits supplied to the Engine Control Module (ECM). The first ignition circuit is provided by the powertrain relay, through a fuse. This ignition 1 voltage circuit supplies power to all the internal ECM circuits associated with the throttle actuator control (TAC) operation. The second ignition 1 voltage circuit is supplied by the run/crank relay through a fuse, and is used to power the remaining internal ECM circuits. If the ECM detects a voltage difference between the 2 ignition 1 voltage circuits, DTC P1682 will set

Read more: http://engine-codes.com/p1682_chevrolet.html#ixzz3dr4CYBUT

When you say travelled 10 miles then would not start, do you mean it would not crank at all, or cranks but doesn't start? If no crank, could be faulty starter motor/solenoid getting heat soaked. If it cranks but won't fire up, more likely bad ignition module, coil, crank or cam sensor. They get hot and can fail just when hot.

your gonna need to plug a scanner in and check the ECM for trouble codes before going any further

The ignition 1 voltage of the Run/Crank relay is more than 3 volts different than the ignition 1 voltage of the power train relay for more than 2 seconds .
if your car is still under warranty run it to the dealer to have this diagnosed, this could be a
complicated process. this could be a problem in the circuit or the ECM( engine control module).

replace the ignition switch usually fixes it

i have the same problem my avalanche wont crank, and the fuel gage dont go up, when the fuel gage works the truck starts but its been two days and it wont crank plz help...

is it an auto or man?