Changed EGR Valve, but still getting OBD error

isuzu
trooper

#1

I had an OBD-II fault indicating EGR Valve - low flow. Replaced the EGR. Seemed to make a difference, but about 50 miles later, the fault returned. Faulty EGR? If not, what’s next? Don’t want to spend another $200 needlessly.


#2

You need to supply some vehicle information…


#3

I thought I did. Sorry, still pretty new at this.
It’s a '96 Isuzu Trooper 3.2 V6. 200K miles.


#4

On some vehicles the main computer needs to be reflashed after installing the new EGR.
But we don’t know what your vehicle is, so it’s all speculation.


#5

The problem might be with the EGR vacuum control solenoid.

Tester


#6

You could have clogging in the port from the exhaust to the valve, or from the valve to the intake manifold, or inside the intake manifold.
Your problem might have been fixed with no more than a few wrenches, gaskets and a bent coat hanger to scrape out the grunge.


#7

No code ever tells you to replace a part - it tells you to check a system.

See Tester & circuitsmith’s posts - it is possible that you had a bad EGR and got another bad one off the shelf - but not likely. More likely is that the “low flow” is from something else. The valves can be tested. The solenoids can be tested, and the ports can be checked and cleaned. I’d move on to the solenoid & ports.