U1019: Electronic Throttle Message Lost on SCP Bus
Diagnostic trouble code U1019 indicates that the powertrain control module (PCM) or another module on the SCP (Standard Corporate Protocol) bus has not received the expected electronic throttle body (ETB) or accelerator pedal position (APP) message within the allotted time. The SCP bus, a Ford implementation of SAE J1850 VPW, carries critical data between the PCM, instrument cluster, and throttle body control module. Loss of this specific message prevents proper throttle control coordination, potentially leading to reduced engine power or a no-start condition.
1. Commonly Affected Makes
2. Most Common Causes
- Open, short-to-ground, short-to-battery, or high resistance in the SCP bus wiring
- Internal failure of the electronic throttle body (ETB) or accelerator pedal position (APP) sensor
- Faulty PCM or receiving module (e.g., instrument cluster) failing to communicate on the SCP bus
- Damaged or missing SCP bus termination resistors
- Electromagnetic interference (EMI) affecting the communication harness
3. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Engine stalls or fails to start
- Unresponsive or erratic throttle response
4. Step-by-Step Diagnosis
Scan for all stored codes and freeze frame data to confirm U1019 and related codes.
Visually inspect the SCP bus wiring and connectors for damage, corrosion, or loose pins.
Measure resistance and voltage at the SCP bus terminals to check for opens, shorts, or incorrect termination.
Test the ETB and APP sensor circuits per manufacturer specifications.
Perform a network communication test to isolate which module is not transmitting or receiving the throttle message.
5. Frequently Asked Questions
Is it safe to drive?▼
No, this code is critical. The vehicle may enter limp mode, stall, or lose throttle control, posing a safety risk. Have it diagnosed immediately.
How much does it cost to fix?▼
Repair costs vary widely: from $100–$300 for wiring repairs to $500–$1,200+ for module or throttle body replacement, plus diagnostic fees.