B1A72-12
B1A72-12-PASSIVE ENTRY ANTENNA 2 - CIRCUIT SHORT TO BATTERY
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
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 communication with the FOBIK is on 20 kilohertz 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 microprocessor continuously 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.
- When Monitored:
At every Passive Entry or Keyless Go action.
- Set Condition:
When the Antenna 2 Signal Circuit is shorted to Battery. If another Antenna has a Short to Ground, a General Electrical Failure or Open DTC, both Antennas will set this Short to Battery DTC.
Diagnostic Test
1. TEST FOR INTERMITTENT CONDITION
NOTE: If another antenna has a Short to Ground, General Electrical Failure or Open DTC, both antennas will set this Short to Voltage DTC.
1. Turn the ignition on.
2. Using the scan tool, record and erase the DTCs.
3. With the scan tool, select: RF Hub, More Options and System Tests.
4. Perform the RF Hub LF Antenna Verification Tests.
5. With the scan tool, read the Active DTCs.
Does the scan tool display: B1A72-12-PASSIVE ENTRY ANTENNA 2 - CIRCUIT SHORT TO BATTERY as active?
Yes
- Go To 2
No
- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
- Perform the BODY VERIFICATION TEST. Body Verification Test .
2. (D922) PASSIVE ENTRY ANTENNA 2 SIGNAL CIRCUIT SHORTED TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the RF Hub C2 harness connector.
3. Turn the ignition on.
4. Measure the voltage between ground and the (D922) Passive Entry Antenna 2 Signal circuit.
Is there any voltage present?
Yes
- Repair the short to voltage in the (D922) Passive Entry Antenna 2 Signal circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test .
No
- Go To 3
3. (D923) PASSIVE ENTRY ANTENNA 2 RETURN CIRCUIT SHORTED TO VOLTAGE
1. Be sure the ignition is still on.
2. Measure the voltage between ground and the (D923) Passive Entry Antenna 2 Return circuit (cavity 14 in the C2 connector).
Is there any voltage present?
Yes
- Repair the short to voltage in the (D923) Passive Entry Antenna 2 Return circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test .
No
- Replace the RF HUB. Radio Frequency Module (RF Hub) - Removal.
- Perform the RADIO FREQUENCY HUB (RF HUB) VERIFICATION TEST. Vehicle Theft Security RF Hub Verification Test.