SES light comes on but ECM will not communicate
08-13-2011, 10:25 AM
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SES light comes on but ECM will not communicate
I have 92 Camaro RS 305 automatic – all stock
Service Engine Soon light comes on after a few minutes running
A couple of parts places and repair shops have hooked up code scanners and all they get is unit will not communicate - no error codes – did the paper clip idea and no codes
Replaced coolant Fan Switch and plug - plug all burned up
Replaced Thermostat switch - plug ok
Put in new air filter, oil, oil filter
Radiator fan will come on only with AC ont
Car will red-line quickly at a stop if AC not on
AC compressor does not kick in
Car runs a little ruff but not bad – have not changed spark plugs in a long while
Found a little coolant on inside of kick cover -passenger side = looks like heater core going out - trying to get top screws out - one day
Took out ECM - opened up and looks brand new inside - not burned up looking
Have diconected battery several times but SES comes back
I bought car new 3 miles on it - now has 127000
It’s like when a woman is brooding but when asked what’s wrong she replies with - nothing’s wrong
So can you guy's tell me whats wrong
Service Engine Soon light comes on after a few minutes running
A couple of parts places and repair shops have hooked up code scanners and all they get is unit will not communicate - no error codes – did the paper clip idea and no codes
Replaced coolant Fan Switch and plug - plug all burned up
Replaced Thermostat switch - plug ok
Put in new air filter, oil, oil filter
Radiator fan will come on only with AC ont
Car will red-line quickly at a stop if AC not on
AC compressor does not kick in
Car runs a little ruff but not bad – have not changed spark plugs in a long while
Found a little coolant on inside of kick cover -passenger side = looks like heater core going out - trying to get top screws out - one day
Took out ECM - opened up and looks brand new inside - not burned up looking
Have diconected battery several times but SES comes back
I bought car new 3 miles on it - now has 127000
It’s like when a woman is brooding but when asked what’s wrong she replies with - nothing’s wrong
So can you guy's tell me whats wrong
08-13-2011, 12:28 PM
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Car: 91' Firebird SOLD
Engine: 350 TPI +bolt-ons
Transmission: 700r4
Axle/Gears: 3:42
Re: SES light comes on but ECM will not communicate
More than likely ecm is still bad. I had a bad ecm for years and didn't know it. Car ran great, but would not communicate with a scanner. Check to see if you have 5 volts on your ALDL data pin.
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