B1A72 Code: Meaning, Causes, and Symptoms | OBD2 Codes
B1A72 – Passive Entry Antenna 2 General Electric Failure
B1A72 Possible Symptoms
Engine Light ON (or Service Engine Soon Warning Light)
B1A72 Possible Causes
Faulty Passive Entry Antenna 2,Passive Entry Antenna 2 harness is open or shorted,Passive Entry Antenna 2 circuit poor electrical connection,Faulty Passive Entry Module (PEM),Faulty Radio Frequency Hub (RF Hub) Module
The Passive Entry (PE) antenna units allow the transmitter within the Radio Frequency Hub (also known as the RF Hub) to communicate via Low Frequency (LF) radio transmission with a FOB with Integrated Key (FOBIK) that is located inside the vehicle or, at most, about 2 meters (6.5 feet) horizontally in all directions around the outside of the vehicle. The RF Hub uses communication through the antenna units to wake up and challenge a FOBIK that is within range in order to authenticate whether that FOBIK is valid (programmed) to the vehicle. The RF Hub communicates with the FOBIK using Frequency-Shift Keying (FSK) modulation. Each antenna unit has two dedicated connections to the RF Hub. One connection is the LF antenna output circuit, while the other connection Is the LF antenna return circuit. These circuits to each antenna unit are a twisted pair to help reduce the potential for induced electrical interference. The RF Hub microcontroller monitors all of the antenna units and will store a Diagnostic Trouble Code (DTC) for any fault that it detects. The hard wired inputs and outputs of the antenna units may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, the most reliable, efficient, and accurate means to diagnose the antenna units requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.