What this code means
B1042 may mean the body control module is seeing a disagreement between the windshield wiper control unit and motor backup signal and the front wiper LIN data.
What the vehicle may do
- Wiper operation may be abnormal or inconsistent.
- The vehicle can store a body electrical fault even if the symptom is intermittent.
Possible fault areas
- Possible BACK_UP(WIPER) circuit issue.
- Possible connector or wiring condition between the wiper control unit and motor and the body control module.
- Possible windshield wiper control unit and motor issue.
Diagnostic path
Opening context
On this Honda CR-V Hybrid, B1042 is a front wiper security line error. In plain terms, the body control module may be seeing a mismatch between the backup wiper signal from the windshield wiper control unit and motor, and the front wiper LIN data. The driver may notice wiper operation that is abnormal or inconsistent, or there may simply be a stored body electrical code. The possible fault areas are the BACK_UP(WIPER) circuit, its connector and wiring condition, or the windshield wiper control unit and motor itself. Start with the basic system checks, and if other codes are present, check what they mean first so you do not chase this one out of order.
Confirm the condition
To begin the B1042 path, turn the vehicle to the ON mode. That sets up the condition needed before moving into the circuit checks for this fault.
Prepare the circuit for testing
Next, power the circuit down as required for the checks, then disconnect the windshield wiper control unit and motor 4-pin connector. After that, disconnect body control module connector A, the 66-pin connector. Before probing, make sure the connector terminal locations are positively identified. If the terminal information is not clear, pause and do not guess at terminals.
Check the BACK_UP(WIPER) circuit for an open
Now perform the inspection in order. With IG Mode OFF, check the BACK_UP(WIPER) circuit between the disconnected windshield wiper control unit and motor connector and the disconnected body control module connector A. For the open-wire check, the normal result is less than 1 Ω. If that result is abnormal, treat it as a circuit problem before moving on.
Check the circuit for a short to ground
If the open check is good, continue with the shorted-circuit inspection method and check the BACK_UP(WIPER) circuit for a short to ground, still with IG Mode OFF. The normal result is more than 1 MΩ. If this test is abnormal, the problem is in the circuit. If the circuit tests normal through this path, the fault points to the windshield wiper control unit and motor.
Verification and takeaway
Keep the verification separate from the circuit testing. Once the fault area has been corrected, verify the repair and confirm B1042 stays gone. The key on this one is to prove the BACK_UP(WIPER) line first: less than 1 Ω for continuity, more than 1 MΩ to ground, and only then condemn the wiper control unit and motor path if the circuit is normal. For more diagnostic training, visit stepdiagnostics.com.
Final check
Prove the BACK_UP(WIPER) circuit first, then use the normal circuit result to guide the final fault direction.
For more guided automotive diagnostics, visit STEP Diagnostics.
