Circuit Description

The engine control module (ECM) provides 5 volts to the following sensors:

• The accelerator pedal position (APP) sensor 1
• The throttle position (TP) sensor 1 and 2
• The cooling fan speed sensor (Trailblazer SS only)
• The crankshaft position (CKP) sensor (2006 Corvette and Cadillac CTSv 6.0 only)

These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together inside the ECM. Therefore, a circuit condition on one sensor 5-volt reference circuit may affect the other sensor 5-volt reference circuits. The ECM monitors the voltage on the 5-volt reference circuit. If the ECM detects that the voltage is out of tolerance, DTC P0651 sets.