No, not a help request but an interesting story....
When #1 son (actually, the only son) got his drivers licence, Dad had
visions of the kid wanting to use the SuperCrew.... I was a kid, once, and
had visions of what could happen to said SuperCrew.... especially hauling a
racing quad up to the track....
So, in a rush, I picked up a 94 F150 4X4 from a guy I thought I could
trust.... so much for that idea..... After the cheque was cashed, I set
about making sure the truck was at least safe.... I can't blame my boy for
not liking the truck... It runs good and everything, it's just not one of
those "fun to drive" feeling units.....
In the mean time, I found a 97 Ranger SC 4X4 with a 4.0... sales dept had
taken it on trade.... high miler but started and ran good - didn't feel to
bad on the test drive. I went through all the 'usual" stuff - changed fluids
and filters - did what brakes needed to be done.... steering, 4X4 system,
you name it - I wanted the kid to have a dependable truck.
But there was a nagging check engine light.... P1445, purge flow sensor
fault. Now, we have to look and see what possible causes there are - and we
find that P1445 is an "electrical" fault. OK... I take a page from AutoZone.
The sensor is only 24 bucks, and the partsmonger orders one.... shows up in
that nights freight cage and I slam dunk the sensor..... After I wiped the
egg off my face, I grab the scan tool and see that that the sensor PID is
pegged at 5 volts.... sensor plugged in - sensor unplugged - sensor shorted
to SIG - sensor shorted to ground... not difference..... Oh, man!?!?! Am I
buyng a PCM? Having the luxury of a breakout box (if you're careful at home,
you can "work around" but do NOT speard any of the pins), I hook it up....
Hmmmm.... open circuit on the SIG_RTN line... Phew! - no PCM in my future (I
To cut a long story short, that includes R&R the intake to be sure the
portion of the harness that passes under it isn't hurtin', we discover that
the engine in this truck is out of a newer truck.... and the portion of the
wiring harness that came with the newer engine had the SIG_RTN assigned to a
different pin in the PCM connector.
Moral of the story.... proper testing saved me the cost of a PCM (about $400
or so CA)... if I had started proper testing early enough, I could have
saved myself enough money to purchase 26 fluid ounces of Mr Seagrams elixir.
Even when we see DTCs generated by a "pattern" failure, we desparately need
to apply some logic and diagnosis to the concern.... I once had a DIY
customer that had purchased several different DPFE sensors.... the first one
he purchased would have been good if he had only hooked the hoses up