What this code means
B1042 may mean the body control module is seeing an inconsistent front wiper security or backup signal compared with front wiper communication data.
What the vehicle may do
- The wipers may behave intermittently or may not match expected module data.
- The code can also be present during body electrical diagnosis even when the symptom is not obvious.
Possible fault areas
- Possible BACK_UP(WIPER) circuit fault.
- Possible connector or terminal condition between the body control module and windshield wiper control unit and motor.
- Possible signal or data mismatch involving the windshield wiper control unit and motor.
Diagnostic path
Opening context
On this 2017 to 2025 Honda CR-V with the 1.5 turbo, B1042 is a front wiper security line error. In plain language, the body control module may be seeing an inconsistent front wiper security or backup signal compared with the front wiper communication data. The wipers may act intermittently, may not match expected module data, or the code can show up during body electrical diagnosis even when the symptom is not obvious. The broad areas to keep in mind are the BACK_UP(WIPER) circuit, connector or terminal condition between the body control module and the windshield wiper control unit and motor, and the signal relationship between those two sides of the system.
Start clean before probing
Before diving into the circuit, start with the basic system checks and follow a structured diagnostic approach. If you are working more than one code, check what those other codes mean first so you do not chase a body network or shared-system issue as if it were only a wiper circuit fault.
Isolate the circuit
Begin by turning the vehicle to ON mode. Then isolate the BACK_UP(WIPER) circuit for testing by disconnecting the windshield wiper control unit and motor 4P connector. After that, disconnect body control module connector A, the 66P connector. At this point, the circuit is separated so the resistance checks can tell you whether the wiring path is open, shorted, or normal.
Check for an open in BACK_UP(WIPER)
With IG Mode OFF, perform the BACK_UP(WIPER) open-wire inspection. A normal circuit has less than 1 Ω. If that check is not normal, stay with the circuit, because the fault is in the BACK_UP(WIPER) circuit.
Check for a short to ground
Next, still with IG Mode OFF, inspect the BACK_UP(WIPER) circuit for a short to ground. A normal result is more than 1 MΩ. If that result is abnormal, the problem is in the circuit. If the open-wire check and the short-to-ground check both come back normal, the diagnostic path points to a problem with the windshield wiper control unit and motor.
Takeaway
The key on B1042 is to prove the BACK_UP(WIPER) circuit first. Do the open check, do the short-to-ground check, and only when the circuit tests normal move your attention to the windshield wiper control unit and motor. For more diagnostic training, visit stepdiagnostics.com.
Final check
Prove the BACK_UP(WIPER) circuit before moving attention to the windshield wiper control unit and motor.
For more guided automotive diagnostics, visit STEP Diagnostics.
