What this code means
B1660 may mean the body control module is detecting an open or disconnected condition in the front interior LF antenna circuit for the keyless access system.
What the vehicle may do
- Keyless access may not recognize the key consistently inside the vehicle.
- Push-button start authorization may be affected if the system cannot confirm the key location.
- The concern may be intermittent if the circuit or connector condition changes with movement or vibration.
Possible fault areas
- Possible front interior LF antenna concern.
- Possible open circuit or connector issue between the antenna and body control module.
- Possible body control module side circuit concern.
Diagnostic path
Code overview
On this 2017 to 2025 Honda CR-V with the 1.5 turbo engine, B1660 points to an open circuit in the front interior LF antenna circuit for the keyless access system. In plain terms, the body control module may be seeing that antenna line as disconnected. The driver may notice keyless access or in-vehicle key recognition acting up, and the possible fault areas can include the front interior LF antenna, its connector and wiring, or the body control module side of the circuit. Start with the basic system checks and follow a structured diagnostic approach before getting into the circuit tests.
Start with scan-tool confirmation
If other codes are present, do not ignore them. Handle the multiple-code path first, especially when body network communication may affect the way the fault is being reported. For B1660 by itself, begin the confirmation with the HDS Self Check. This keeps the diagnosis tied to what the body control module is actually seeing right now.
Check the LF antenna circuit for an open
Next, isolate the front interior LF antenna circuit. Disconnect the front interior LF antenna 2P connector, then disconnect body control module connector C, the 66P connector. With those connectors separated, check the EXT_F+ and EXT_F- open-wire inspection paths. Normal for each side, with the open-wire inspection OFF, is less than 1 Ω. If either side is not normal, treat it as a circuit problem and stay with the wiring and connector side before moving on.
Check the body control module side
Once the external circuit checks normal, move to the body control module inspection. This inspection can be done earlier because it includes the listed checks, but if it fails, you still have to break the testing back down item by item to find which part of the inspection failed. For this check, disconnect the front interior LF antenna 2P connector and perform the module internal circuit inspection. The normal result is Voltage with the inspection ON. There is also a note tied to permanent power supply, so vehicle mode ON versus OFF, LOCK, is not the deciding factor for that voltage check. If this inspection is abnormal, the problem is on the body control module side of the diagnosis.
When the circuit and module checks pass
If the open-wire inspection is normal and the body control module inspection is normal, the remaining item in this diagnostic path is the front interior LF antenna. At that point, the procedure determines there is a problem with the front interior LF antenna. Keep the logic in order: prove the circuit, prove the module-side check, and only then call the antenna the remaining cause.
Takeaway
The key to B1660 is not guessing at the antenna first. Confirm the code, check the two antenna circuit legs for an open, verify the module-side voltage check, and let the test results decide whether the fault is in the circuit, the body control module side, or the front interior LF antenna. For more diagnostic training, visit stepdiagnostics.com.
Final check
B1660 is best approached by confirming the code, checking the antenna circuit for an open, then using the module-side inspection before deciding what remains at fault.
For more guided automotive diagnostics, visit STEP Diagnostics.
