no voltmeter, working blind.
my guess engine runs ok>? huh? 3.2 or 3.5L or?
and only 2 codes (DTC'S) right ?>
can it be,,, well it can be lots of things..
you never said what engine is there, must we guess that.
to fix any engine, we need to know, what it IS first
then remove wallet and see, ok i live canada or not.
as you may not know smog parts vary by COUNTRIES LAWS.
so ill pretend you said USA on this USA forum........ what else can i do?> but beg locations.........
first off the answer to your question is yes, and for all cars from 1988 to now...(ECU based EFI cars)
but why assume the worst case. why not do the tests.
why not read the manual on the car the FSM, (alldata.com)
see how it works
its and electric motor driven EGR, and with a feed back sensor.
i dont have the DTC list. in usa documents or hard to find on this mostly dead car maker here..... (find dealer and a book? good luck)
best i can tell is 402 is excessive. and that means
the feed back is stuck wide open. bad egr main. end story.
P1404 (that 1 means factory code only) custom.
and means opposite of 402.....
cleaning the exhaust path was best ploy.
now it can flow, so next is the valve must open and close
with PCM control
and last the read back sensors most work.
one way (sometimes works) is to leave the EGR connected
but removed from engine
key on 3 times
and see if the EGR does a reset cycle.
some cars the EGR will cycle 1 time, each key, on the smart hope that doing so, can unstick it and not allow engine to stall.
so look doing that.
if that works the readback sensor is bad. see below as ?
ive done may EGR system.s and helped trainees'
let me do EGR rules.
1:exhaust path clear.
2: motor above on pin 1 and 3 works.
3: read back on pin 1 works.
keep in mind the EGR may work perfect and zero NOX pollution,
but if pin 1 lies (bad pot). telling PCM its bad and is NOT.
keep that in mind.
and pin 4 must be at 5v or the sensor will be dead.
I think this pin 5 is PWM modulated. at poin 3
and 12vdc at pin 5 for pwer.
pin 2 is ECU quite ground, 0v.
the car is old the EGR main is old
what is the chance the main this old is still good, not much in IMO.