1991 Chevy Camaro DTC 33

Disconnecting the battery should reset the code if light come right back its a hard failure and you need to check more check vacuum line make sure you have good vacuum on it CODE 33, MAP SENSOR SIGNAL VOLTAGE HIGH

1.This test confirms Code 33 and determines if it is the result of a hard failure or an intermittent condition. Code 33 will set when voltage signal reading is too high for greater than a precalibrated period of time, TPS voltage indicates throttle is closed and neither Code 21 or 22 is present. 2.This step simulates conditions for a Code 34. If the control module recognizes and sets Code 34, low MAP signal, the control module and 5-volt reference and MAP signal circuits are not at fault. If ground circuit is shared with other sensors and ground circuit becomes open, additional codes related to these sensors may be set. Diagnostic Aids With the ignition switch in the ON position and the engine stopped, manifold pressure is equal to atmospheric pressure and the signal voltage will be high. Comparison of the BARO readings from a known good vehicle using the same sensor is a good way to check the accuracy of the suspected sensor. Readings should be the same within +/- .4 volt. Code 33 will result if ground circuit is open or MAP signal circuit is shorted to voltage or to 5-volt reference circuit