C1447 Traction Control Request Circuit Malfunction
The C1447 code indicates a fault in the traction control (TRC) request circuit. This Toyota/Lexus-specific code is triggered when the Skid Control ECU detects an anomaly in the communication signal or request circuit between the traction control module and other ABS or VSC modules. The system uses a CAN network to coordinate traction control intervention with engine and brake controls; when this request is not processed correctly, the fault code is stored. The code may set during startup or normal operation when the Skid Control ECU fails to receive the expected request signal from the traction control module, or when the signal is erroneous or intermittent. This can result in deactivation of the traction control system and, in some cases, the vehicle stability control (VSC) system.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty traction control (TRC) module
- Damaged Skid Control ECU
- Open or short circuit in the request circuit wiring
- Corrosion or damage in ABS/brake system connectors
- CAN communication network fault (wiring or terminators)
- Ground issue in the control module
- Outdated or corrupted ECU software
3. Symptoms You Will Notice
- Traction control system inoperative
- Vehicle stability control (VSC) system disabled
- ABS warning light illuminated
- Check engine light may be on
4. Step-by-Step Diagnosis
Scan for all stored codes and freeze frame data
Inspect wiring and connectors for damage, corrosion, or loose connections
Test CAN bus communication for continuity and proper voltage
Check ground connections at control modules
Perform module communication tests using a scan tool
Update ECU software if applicable
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, but with reduced traction and stability control. Drive cautiously, especially in slippery conditions.
How much does it cost to fix?▼
Diagnosis $100-$200; repair costs vary widely from $200 for a wiring fix to $1,500+ for module replacement.