My truck gets over heated
Unlikely. My feeling is that your Durango
will start and run as if nothing ever happened when you go to turn the
rental back in. Your well-detailed post describes a classic PCM hot-soak failure for this model.
While
any module in any vehicle can fail (at any time), the 56040147A# JTEC
engine controller is bar far the worst offender in our stables. Its
typical mode of failure is very similar to what you've seen, down to
losing gauge operation. Gauge information is bussed over to the
instrument cluster from the PCM and when it's crashed, you won't see
anything displayed. Given enough ignition on-time, the odometer will
often flash <NO BUS> in place of vehicle miles.
Heat is a
common enemy to these controllers. While underhood heat can be
considerable any time of the year, the addition of air conditioning
heat loads to the underhood area bakes everything to a higher level.
The short wait at the airport was apparently just enough to push the
hot-soak levels to the point where it acted up for the first time.
The
PCM will also die while driving, more so on hot days. Each time it
returns from the dead, it will behave as if nothing ever happened...
it's a brand new world! When scanned, the PCM will show no learned
memory, things like fuel system adaptive values, Misfire Monitor
adaptive numerator values or restart counts. The carb readiness (used
for emission testing) will be reset to NOT DONE.
So much of the
evidence concerning PCM failure is actually the LACK of evidence...
nothing retained in memory. One place that might hold a clue is the
antilock brake system. If ABS stored a code indicating a VIN mismatch,
it's because the PCM wasn't awake to confirm the match. This is one of
the few places you can go to see if something noticed the failure (and
it doesn't always work).
A second possibility for what you've
seen could be the shorting of the 5v power supply from the PCM to the
MAP, TPS, cam sensor, crank sensor and transmission governor pressure
sensors. A short in this circuit takes the PCM down like a rock and
will give you the same appearances with the gauges. If the engine still
won't start when you get back to the airport, I'd consider this
possibility. If it starts and runs fine, the PCM still ranks #1. If
you'd like detailed pinout instructions for testing, I'd be happy to
shoot you some things to check. All you'll need is a digital voltmeter.
If
you decide to replace the PCM, you can do it yourself. It's a
plug-and-play controller in this year, but will need to be programmed
with the Durango's VIN and vehicle miles at the dealer. Without the VIN
programming, the ABS lamp will be lit forever because of the perceived
mismatch. The PCM is held to the fenderwell by three 5/16" (8mm)
hex-head sheet metal screws. The connectors are pressure clasp release
types... not tool required. An open-end wrench in either of these sizes
will work fine.
The PCM is located on the right side fenderwell
area, between the fender and the air cleaner body... it's the
three-connector unit. The actual part number will be printed on a white
label, a good thing to check before ordering a replacement.