Note on Intermittents

If an intermittent Code 33 is being set, manipulate related wiring while observing engine data parameters .0.2 and .0.3. If the failure is induced, one of the pressure sensor readings will change to produce a larger "correlation" difference. This will help to isolate the location of the malfunction.

Code 33 is more difficult to induce if the "outside temperature" reading is not between 50°F and 130°F. The ECM allows for a greater difference between the pressure sensors if the ambient temperature is extreme.