U1071 SCP Network Communication Failure
The U1071 code indicates a communication fault on the SCP (Standard Corporate Protocol) network, which is based on the SAE J1850 standard. This network is used primarily by Ford for internal communication between control modules. The code sets when the powertrain control module (PCM) or another module receives invalid or missing data from engine sensors. The fault occurs when a transmitting module fails to send sensor information correctly over the data bus, or when the receiving module detects a corrupted, out-of-range, or incomplete data frame.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty PCM or specific transmitting module
- Short circuit or open circuit in the SCP communication bus (J1850 network wires)
- Damaged, corroded, or loose SCP bus terminals
- Electromagnetic interference (EMI) affecting communication wiring
- Recently replaced control module not properly configured (not programmed)
- Internal engine sensor failure sending erroneous data to the transmitting module
3. Symptoms You Will Notice
- Check Engine Light illuminated
- Drivability issues such as rough running, stalling, or poor acceleration
4. Step-by-Step Diagnosis
Scan for all stored codes and freeze frame data
Visually inspect SCP bus wiring and connectors for damage, corrosion, or loose connections
Check for any aftermarket accessories that may cause EMI
Test bus resistance and voltage at the OBD2 DLC (typically 2.5V on J1850 PWM)
If a module was recently replaced, verify it is programmed correctly
Perform a network communication test to isolate the faulty module
5. Frequently Asked Questions
Is it safe to drive?▼
The severity is medium. You may be able to drive, but drivability issues like stalling or poor acceleration could occur. It's best to diagnose and repair promptly to avoid further damage.
How much does it cost to fix?▼
Costs vary widely depending on the cause. Simple wiring repairs may cost $100-$300, while replacing a faulty PCM can range from $500-$1,500 including programming.