Ford F150 1996 – H1X2 ECM Capacitor Overhaul and P0122

Описание: No electrolytic capacitor lasts forever. They may even check
good but fail in the circuit. Old ones must be replaced
whether leaking or not. A leaking capacitor likely damages
the PC traces and with enough time ruins the whole PCB. As a rule,
electrolytic capacitors should be replaced every fifteen years.

Tag = H1X2. Computer case casting date 1995.

For the 1996 manual truck shown, replace these noting that the
original voltages could not be found.

C7 - 47uf 10v replaced with 47uf 16v 105 degree C
C2 - 3.3uf 63v replaced with 3.3uf 160v 105 degree C

Parts may be difficult to get and some subs may have
to be used. Voltages may be substituted with higher values.
Can size is not critical as long as it fits. However, the
high temperature rating is critical. Never use ordinary
replacement parts in any ECM.

There are numerous demos for desoldering on the Internet.
One approach was demoed here. It may take a long time to remove
the capacitors. Never use a drill on a board like this one
with plated through holes since part of the circuit could
become disconnected. Avoid prolonged heating of the PCB.
Don't touch anything on the board other than the capacitor
leads. Remove all traces of flux and solder from the PCB.
Replace the insulating coating wherever it was disturbed.

Because the DIY repair person is a variable, it may be a
good idea to replace components one at a time and then
immediately test the ECM. That way any issues are trackable
to the last repair effected without as much guessing.

There are people who specialize in ECM repair. The work could
be sent out to them, but beware. There's no way to verify
exactly. It's not free either and there could be a significant
delay in returning the ECM.

Replacing the computer completely will require reprogramming.
Try to keep the existing computer if at all possible. The swapped
one may not be as good. Each has a serial number on it that
is key to knowing how the vehicle was set up at the factory.
Save the original number as it is the genesis for the vehicle.
That is the number that will be re-entered when a total reset is
required. Any other number may result in all sorts of problems.
Ford keeps and maintains these numbers indefinitely. They may
apply factory updates to the profiles without any notice.

Note: The loaded programs never were intended to support alcohol
fuels. Any special field updates may need to be redone when
replacing the entire ECM. Ford provides free downloads of the
service software.

Forscan is a free Ford Specific Diagnostic Software:
Download Here- https://forscan.org/home.html

There are demos for using the software on
YouTube. Also, there are some significant differences between
ECMs for manual versus automatic transmissions. Never just buy
something without fully qualifying it.

Symptoms, Observations and Oddities

The ECM demonstrated may or may not have been part of a
high idle issue, P0122. However, funny incurable and intermittent
symptoms may mean the ECM could have issues. Not shown was
another problem noticed. The odometer did not kick over to the next
sequential 100,000 count when hitting 400,000 miles. That
could be a processor limitation? Feel free to comment. It may be
settable with software. Not sure. This repair was effected with only
simple tools as shown.

Weak batteries affect signals going to the ECM as could bad wiring.
Over time, the ECM may have to be reloaded or replaced. Capacitors
are variables that should not be tolerated. They should be replaced. It seems that
the nichicon brand of capacitors is the best one to use. Feel free to comment.
C2 appears to be a power circuit filter, probably to remove alternator whine, a guess.
C7 appears involved in a logic area that may have something to do with signal
damping. It's hard to say, but some logic components start bouncing on/off if
minute amounts of noise aren't attenuated, filtered. Logic ICs age too. They become
intermittent as they decline making diagnosis unusually difficult. Only advanced repair
skills help at that point.

Update
So far P0122 /1120 have not been set. Previously the usual things were done including
replacement of the TPS and cleaning of the butterflies in the throttle body. The P0122
kept getting set randomly after two years had elapsed from the time the TPS was
replaced. Nothing in the wiring appears bad, but with this animal it's always been
about the finer points. Some owners may replace the whole throttle body and the
sensor, but that could be misguided desperation. Usually, there have been a
number of episodes of high idle before the P0122 sets. Sometimes it is detected, but
not reported over an entire year. No specific temperatures seem involved. It's just a
gremlin. The vehicle demoed has a hard connection between the pedal and the
throttle body, making the P0122 all the more perplexing, but fortunately the engine
does not over rev in use. This part of the notes will be updated with any changes .