P1656 & Clogged Cat
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).
Dave
Completely Fried. Toasted. Burned up.
New 3" down pipe and 4" exhaust new in box.
'99 Suburban 1500. 8 Lug Wheels.
Code F (As in Fried) Engine.
4 Speed Automatic Heavy Duty Transmission.
3.42 rear axle ratio
Heavy Duty Trailering Equipment.
Heavy Duty Auxiliary Transmission Cooling System. 8,050 GVW Rating.
New Power Steering Pump.
New Alternator.
New Wastegate Vacuum Soleniod.
New Front Blower Motor.
Plugged rear A/C Lines. Now leaking again. No A/C.
Newer Fuel Injection Pump.
Newer PMD with Heat Sink.
177,000 + Miles.