Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.
Circuit Description
PCM has internal tables that compare MAP sensor values with TP sensor values. MAP sensor is a variable resistor that responds to changes in intake manifold pressure. The voltage ranges from 1.0-1.5 volts at idle (high manifold vacuum) to 4.0-4.5 volts at wide open throttle (low manifold vacuum).
TP sensor is a potentiometer which responds to changes in throttle plate angle. At closed throttle position, output of the sensor is low (about.5 volt). As the throttle plate opens, the output signal increases so that at wide open throttle, the output will be high (about 5 volts).
DTC will set if MAP or TP sensor value is out of range for greater than 2 seconds when DTC P0107, P0108, P0122, P0123, P0506 or P0507 is set, engine speed is 1600-4000 RPM, engine speed change is less than 100 RPM, EGR commanded steady, A/C command is unchanged, and IAC change is less than 10 counts.
Diagnostic Aids
DTC will set if either MAP or TP sensor is out of range. To distinguish which one failed, review malfunction history information on scan tool and attempt to duplicate conditions.
Check sensor and PCM connection for corrosion. Check for proper terminal connections. With ignition on, engine off, MAP reading should be the same as BARO reading because manifold pressure is equal to atmospheric pressure (no vacuum-high voltage). Comparing this reading to a known-good vehicle with the same sensor is a good way to check accuracy of suspect sensor. Reading should be within 0.4 volt. See appropriate SENSOR OPERATING RANGE CHARTS article.