SCP Network Communication Error U1175
The U1175 code indicates a communication fault on the SCP (Standard Corporate Protocol) network, which uses the SAE J1850 PWM physical protocol. This means a control module on the network has received invalid data or failed to receive expected data for a specific Primary Id. This disrupts or corrupts data transmission between modules, preventing receiving modules from properly executing shared control functions and causing a network communication failure.
1. Commonly Affected Makes
2. Most Common Causes
- SCP (J1850) network wiring shorted to ground or voltage
- Open or high-resistance SCP network wiring
- Damaged control module connector or corroded pins
- Faulty transmitting or receiving control module
- Severe electromagnetic interference (EMI) in the main harness
3. Symptoms You Will Notice
- Check Engine Light or other warning lights illuminated
- Erratic behavior or failure of multiple control systems (e.g., transmission, ABS, instrument cluster)
4. Step-by-Step Diagnosis
Scan for all stored codes and note freeze frame data
Visually inspect SCP network wiring and connectors for damage, corrosion, or shorts
Measure resistance across the SCP network bus (should be around 60 ohms with two terminators)
Check for voltage on the bus (should be around 2.5V with no activity, pulsing during communication)
Isolate modules by disconnecting them one at a time to identify the faulty module
5. Frequently Asked Questions
Is it safe to drive?▼
The vehicle may still be drivable, but you may experience reduced functionality or erratic behavior of multiple systems. It is recommended to diagnose and repair the issue promptly to avoid further damage.
How much does it cost to fix?▼
Repair costs vary widely depending on the root cause. Simple wiring repairs can cost $100-$300, while replacing a control module may range from $500-$1500 including labor.