What this code means
B1662 may mean the body control module is detecting an open condition in the middle interior LF antenna circuit used by the keyless access system.
What the vehicle may do
- The vehicle may have keyless access or interior antenna detection issues.
- The concern can be intermittent if the circuit or connector condition changes with movement or vibration.
Possible fault areas
- Possible antenna circuit wiring or connector issues.
- Possible body control module side circuit issue.
- Possible middle interior LF antenna issue.
Diagnostic path
Opening and code logic
For B1662 on this CR-V Hybrid, the keyless access control unit is flagging a middle interior antenna circuit open condition. In plain terms, the body control module may not be seeing the expected circuit path through the middle interior LF antenna line. The vehicle may have keyless access or interior antenna detection issues, and the possible fault areas can include the antenna circuit wiring, connector condition, the body control module side of the circuit, or the middle interior LF antenna itself. Start with the basic system checks, and if other codes are present, check what they mean first so you do not chase this code out of context.
Initial scan-tool check
Once the preliminary checks are handled, run the HDS Self Check. Use that to confirm the current fault picture before disconnecting anything. From there, keep the diagnosis focused on the target circuit instead of jumping straight to a module or antenna call.
Open-wire inspection setup
Next is the EXT_R plus and EXT_R minus open-wire inspection. Prepare the circuit by disconnecting the middle interior LF antenna 2-pin connector and body control module connector C, the 66-pin connector. Make sure the connector and terminal identification is correct before probing; do not guess at terminals if the connector view is not clear.
EXT_R circuit check
With those connectors disconnected, check the EXT_R plus and EXT_R minus circuits according to the inspection table. For the EXT_R plus open-wire inspection with the circuit OFF, the normal result is less than 1 Ω. For the EXT_R minus open-wire inspection with the circuit OFF, the normal result is also less than 1 Ω. If either result is abnormal, call that a circuit problem and stay on the wiring and connection side of the diagnosis.
Body control module side check
Only move into the body control module inspection after the external circuit checks normal. For this inspection, disconnect the middle interior LF antenna 2-pin connector. Then perform the module internal circuit inspection. The expected result is voltage. If that inspection is abnormal, the fault points to a problem with the body control module. One important note: even if this module-side inspection is used early, a failed result still has to be broken down with the individual circuit checks so you know what actually failed.
Antenna conclusion and verification
If the other inspection items all indicate a normal condition, the remaining fault area is the middle interior LF antenna, and the diagnosis points to a problem with that antenna. After any correction, keep verification separate from the testing path: run the appropriate checks again, confirm the code does not return, and make sure the keyless access concern is resolved. The takeaway is simple: prove the EXT_R circuit first, prove the body control module output next, and only then land on the middle interior LF antenna. For more diagnostic training, visit stepdiagnostics.com.
Final check
This diagnosis is about separating an open circuit problem from a module-side problem, then only considering the antenna after the earlier checks are normal.
For more guided automotive diagnostics, visit STEP Diagnostics.
