Technician A says that some wiper systems will set a diagnostic trouble code. Technician B says that a faulty control module in a wiper system requires replacement. Who is right?

• A. A only
• B. B only
• C. Both A and B
• D. Neither A nor B

Answer: (C)

The wiper system often has its own electronic control and can be monitored by the vehicle’s diagnostic system. When a fault is detected—such as a motor stall, park switch issue, or intermittent wipe—the system can log a diagnostic trouble code in the vehicle’s computer. That means the first technician’s statement is true: some wiper problems will generate a DTC to help with diagnosis.

If the wiper control module itself is faulty, the usual remedy is replacement. These control modules are compact electronic units, and when they fail they often aren’t repairable in the field. Replacing the module restores proper control of the wipers and resolves faults that the module itself is causing. So the second statement is also true.

Since both diagnostic codes can appear for wiper problems and a faulty control module typically requires replacement, both technicians have valid points.