U1193 SCP Bus Communication Failure
The U1193 code indicates that a control module has detected invalid communication or missing data on the SCP (Standard Corporate Protocol) bus, which is Ford's proprietary implementation of the SAE J1850 protocol operating at 41.6 kbps using PWM or VPW. This code sets when a module (such as the PCM, GEM, IC, or ABS module) expects a periodic message with a specific primary identifier but does not receive it, or the received data is corrupted, out of range, or does not conform to the defined format. This typically affects communication between Ford modules like the PCM, instrument cluster, body control module, or ABS module.
1. Commonly Affected Makes
2. Most Common Causes
- icon icon-cause">🔧Faulty transmitting module (PCM, GEM, IC, ABS, etc.) that generates the message with the primary ID
- Open or short circuit in the SCP bus wiring (J1850 data pins 2 or 10 on the DLC)
- Bus termination resistance out of specification (typically 120 ohms per side in differential configuration)
- Electromagnetic interference corrupting bus signals
- Internal failure of the receiving module that misinterprets valid data
- Poor connection at the DLC or splices in the communication harness
- Weak battery or voltage fluctuations affecting module reference
3. Symptoms You Will Notice
- Check Engine Light or other warning lights illuminated
- Intermittent or complete loss of communication with certain modules
- Malfunctioning gauges, warning chimes, or driver information display
- Erratic transmission shifting or ABS operation
- No-start or stalling in severe cases
4. Step-by-Step Diagnosis
Scan all modules for related communication codes and freeze frame data
Inspect the DLC and SCP bus wiring for damage, corrosion, or loose connections
Measure bus termination resistance at the DLC (pins 2 and 10) – should be approximately 60 ohms total
Check battery voltage and charging system for stable power
Perform a network test to isolate the non-communicating module
If a specific module is identified, inspect its power, ground, and bus connections
5. Frequently Asked Questions
Is it safe to drive?▼
The severity is medium. You may be able to drive short distances, but symptoms like erratic transmission or ABS behavior can compromise safety. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
Costs vary widely depending on the root cause: from $50–$150 for a wiring repair to $200–$800+ for module replacement. Diagnostic fees typically range $100–$200.