What this code means
B1660 may mean the keyless access control unit is detecting an open condition in the front interior low-frequency antenna circuit.
What the vehicle may do
- Keyless access operation may be inconsistent.
- One-push start operation may be affected if the key is not detected normally inside the cabin.
- The concern can be intermittent if a connector or wire contact changes with movement.
Possible fault areas
- Possible front interior LF antenna issue.
- Possible connector, terminal, open wire, or high-resistance condition between the antenna and the keyless access control unit.
- Possible keyless access control unit output-side issue.
Diagnostic path
Opening context
On this Accord, B1660 points to an open-circuit fault in the front interior LF antenna circuit for the keyless access system. In plain terms, the keyless access control unit may not be seeing the antenna circuit the way it expects to. The customer may notice keyless access or one-push start behavior that feels inconsistent, especially when the system needs to detect the key inside the cabin. Broadly, this can come from the antenna itself, the connector and wiring between the antenna and the keyless access control unit, or the control unit’s output side. We’re going to work the fault in that order: confirm the code, check whether the control unit can drive the antenna circuit, then check the wires for an open or high resistance.
Confirm the fault first
Start by clearing the DTCs with the HDS. From the HDS mode menu, go into the self check, run the self check, then check for DTCs again. If B1660 does not come back, treat it as an intermittent failure. The system is OK at that moment, so concentrate on loose terminals, poor connector fit, or a connection that may open up with vibration or movement. If B1660 is indicated again, continue into the front interior LF antenna circuit checks.
Check control unit output to the antenna circuit
For the EXT F plus and EXT F minus line output check, press the engine start/stop button to put the vehicle in OFF mode. Disconnect the front interior LF antenna 2P connector. Then press the engine start/stop button again to select ON mode. On the HDS, select Keyless Access Control from the One-Push Start system menu, and enter Functional Tests. Connect the voltmeter across the front interior LF antenna connector: test point 1 is terminal No. 2, the GRN wire, and test point 2 is terminal No. 1, the BRN wire. Now select Cabin Front Antenna with the HDS and watch for voltage. If voltage is present during that command, replace the front interior LF antenna. If there is no voltage, move on to checking the circuit between the antenna and the keyless access control unit.
Check the wiring for an open or high resistance
Next, put the vehicle back in OFF mode. Disconnect keyless access control unit connector A, the 32P connector. With the keyless access control unit connector and the front interior LF antenna connector both disconnected, check continuity through each circuit. For the EXT F plus circuit, check from keyless access control unit connector A No. 32, the GRN wire, to the front interior LF antenna 2P connector No. 2, also GRN. For the EXT FR F minus circuit, check from keyless access control unit connector A No. 16, the BRN wire, to the front interior LF antenna 2P connector No. 1, also BRN. If continuity is good on the checked circuits, replace the keyless access control unit. If continuity is not present, repair the open or high resistance in the wire.
Takeaway
The clean way through B1660 is to prove whether the code is active, command the cabin front antenna output, and then separate an antenna fault from an open wiring fault or a control unit output fault. Do not skip the connector checks if the code is intermittent. For more diagnostic training, visit stepdiagnostics.com.
Final check
B1660 is best approached by confirming the code, checking commanded antenna output, then proving wiring continuity before making the repair decision.
For more guided automotive diagnostics, visit STEP Diagnostics.
