U1142 SCP Bus Invalid Data
The U1142 code indicates that a control module has detected missing or invalid data on the SCP (Standard Corporate Protocol) communication bus, specifically for a primary identifier. SCP is a Ford-proprietary serial network used in Ford, Lincoln, and Mercury vehicles from the mid-1990s to around 2010, operating at 41.6 kbps with PWM or FSK modulation. This fault means one module did not receive the expected message from another module, or the data received is corrupted, out of range, or does not match the defined format for that identifier.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty transmitting control module sending incorrect data
- Electrical interference or noise on SCP bus circuits 914 and 915
- Abnormal resistance in SCP communication lines
- Receiving control module with internal data interpretation failure
- Poor connections or corrosion in SCP bus connectors
- Bus voltage out of specification (should be between 0V and 5V)
3. Symptoms You Will Notice
- Check Engine Light or other warning lights on
- Intermittent or complete loss of communication between modules
4. Step-by-Step Diagnosis
Scan all modules for related codes and check for communication faults
Inspect SCP bus wiring and connectors for damage, corrosion, or loose connections
Measure resistance and voltage on SCP bus circuits (914 and 915) to verify within spec
Test for electrical noise or interference on the bus with an oscilloscope
Isolate the faulty module by disconnecting modules one at a time and monitoring bus activity
5. Frequently Asked Questions
Is it safe to drive?▼
The vehicle may still be drivable, but you may experience intermittent communication issues or warning lights. It is recommended to diagnose and repair the fault promptly to avoid potential drivability problems.
How much does it cost to fix?▼
Diagnosis typically costs $100-$200. Repair costs vary widely: a simple wiring fix may be under $100, while replacing a control module can range from $200 to $800 or more, depending on the module and labor.