Diagnostic Aids
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
A RPS signal voltage that remains low 0.5 or lower indicates a short to ground on the RPS signal voltage circuit. It can also indicate an open or high resistance on the RPS low reference signal circuit.