Hello!

Does anyone know if the back pressure from a clogged cat would cause the P1656 Wastegate Solenoid control circut code?

My burb has 173,000 miles, and I suspect it has the original Cat Converter. I've always thought it was clogged due to difficulty towing, but can't get the damn thing loose to install a "test" pipe...

I did all of the tests (vacuum and boost pressures normal), even replaced the Solenoid and the sensor on top of the intake manifold.

During my testing, I did notice that the boost would sometime spike to over 12 PSI... the pressure would always drop back down quickly.

This code is intermittent, and only comes on after a long trip on the expressway (no load).