what the...?
Ideas?
Ideas?
20,21,22 are used any time the canister purge (evap system) is not running.
Canister purge has serveral qualifications to run. Engine restart time is one of them.
20 shows up during low TPS (2%), and low vehicle speed (3MPH). 21, 22 jump back and forth depending on where the current manifold pressure is for the lower LTFT MAP value.
GM used to use a lookup table to see what BLM cell canister purge was allowed in. It was never allowed in lower MAP, lower RPM ranges.
Now they do the opposite. It's allowed in all BLM cells, and jumps to it's own BLM cells when it's off. Depending on what calibration you have, the normal CCP BLM switch point is less than 4% CCP duty cycle.
Super Sport X2


