U1185 Wiper System Bus Communication Fault
The U1185 code indicates that a control module (such as the GEM, Front Electronic Module, or Body Control Module) has detected invalid or missing data on the SCP (Standard Corporate Protocol) bus related to the windshield wiper and washer system. The SCP bus is a serial communication network used by Ford Motor Company in vehicles from approximately 1996 to 2006, operating at 41.6 kbps with pulse-width modulation on a single wire. This code sets when a module expects to receive status messages from another module about the wiper/washer system, but the data is incorrect, incomplete, or not received within the expected time.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty wiper system control module (GEM, FEM, or body control module)
- Open or short circuit in the SCP bus wiring (SCP+ and SCP- lines)
- Incorrect bus termination (damaged 120-ohm resistors)
- Faulty wiper switch/selector with SCP bus communication
- Corrosion in SCP bus connectors affecting signal integrity
- Control module with outdated or corrupted software
- Low system voltage affecting bus communication
3. Symptoms You Will Notice
- Wiper or washer system inoperative or intermittent
- Other SCP bus-related faults or warning lights
4. Step-by-Step Diagnosis
Scan for additional codes and check freeze frame data
Inspect SCP bus wiring and connectors for damage or corrosion
Measure bus termination resistance (should be ~60 ohms with two 120-ohm terminators)
Check for proper voltage and ground at the wiper control module
Test wiper switch and module communication using a scan tool
Update or reprogram the control module if software is suspected
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, the vehicle is generally safe to drive, but the wiper and washer system may not function properly, which could be a safety hazard in rain or snow.
How much does it cost to fix?▼
Diagnosis typically costs $100-$150. Repairs range from $50 for a wiring fix to $500+ for module replacement, depending on the cause.