Circuit/System Description

WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The manual apply switch rationality diagnostic monitors for circuit rationality faults on the manual apply switch input. The manual apply switch consists of a primary circuit, which is used as the basis for determining the trailer brake manual apply gain, and a redundant circuit that is used to rationalize performance of the primary circuit.

Manual Trailer Brake Apply Request Switch Signal Invalid" diagnostic monitors for a manual apply switch that is stuck in an applied position.

Manual Trailer Brake Apply Request Switch Signal --plausibility failure diagnostic monitors for circuit rationality faults on the manual apply switch input. The manual apply switch consists of a primary circuit, which is used as the basis for determining the trailer brake manual apply gain, and a redundant circuit that is used to rationalize performance of the primary circuit. The manual apply switch position fault is detected when the absolute value of the difference between the primary manual apply switch input and redundant inputs exceeds a threshold for a certain amount of time.