Diagnostic Aids
WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
If DTC P1635 or P1639 are also set, a short to voltage on the 5-volt reference circuit may exist. See DTC P1635: 5-VOLT REFERENCE 1 CIRCUIT or DTC P1639: 5-VOLT REFERENCE 2 CIRCUIT .
Use a scan tool to monitor TP sensors as accelerator pedal is slowly depressed. The voltage should change smoothly from 3.14 volts at 33 percent throttle, to 0.59 volt at wide open throttle for TP1 and 1.86 to 4.39 volts for TP2.
Inaccurate readings will occur if resistance measurements are taken on a MAP sensor. The MAP sensor contains an internal amplifier circuit that requires applied voltage to function properly.
This DTC will set if a manifold vacuum leak is present.