1. So you want to be a automotive tech
Is there any security
in being a auto technician these days?

2. Where are we headed ???? The Average Ford 2003 2013 15 Modules 60
over a ten year period
2003
2013 15
Modules 60
(micro computers)
2-3 million
Lines of Software code
10 million

3. Catalyst System Efficiency Below Threshold Bank 1
What if
that Ford set a code P0420
Catalyst System Efficiency Below Threshold Bank 1
According to Ford Service Info
there are only 13 possible causes

4. That can take you under the car That can take you Under the car
Exhaust manifold
Catalytic Converter
Tailpipe
H02S
Or under the hood
ECT sensor
Oil Contamination
Cylinder misfiring
Fuel Injectors
Timing
or even to the fuel type (leaded)

5. to figure out the problem
If you want to go from
13 potential causes
to the fix
You NEED a technicain
to figure out the problem
unless you diagnose the underlying problem,
the code will continue to be set time after time.

6. Remember the KISS principal ?
most systems work best if they are kept simple
rather than made more complex
seeing that automotive engineers
are moving away from the KISS principal
That sure sounds like job security to me.