Circuit/System Description
WARNING: This page is about a different car, the 2010 GMC Sierra and 2010 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The engine control module (ECM) has 2 internal 5-volt reference circuits. Each internal reference circuit provides external 5-volt reference circuits to more than one sensor. A short to ground or short to voltage on one external 5-volt reference circuit can affect all the components connected to the same internal 5 V reference circuit.