U043C: Invalid ACC Right Distance Sensor Data
The U043C code indicates that the receiving control module (typically the adaptive cruise control module or PCM) has detected invalid, implausible, or out-of-range data from the right front distance sensor of the adaptive cruise control (ACC) system. This points to a failure in CAN communication integrity or in the sensor signal itself, causing the automatic braking and distance-keeping functions to be disabled.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Faulty or contaminated right front distance sensor (radar/lidar) due to dirt, ice, or impact damage
- Open, shorted, or high-resistance wiring or connectors between the sensor and the receiving module
- Internal failure of the adaptive cruise control module or PCM
- Physical misalignment of the sensor after a collision or body repair
- Software error or version incompatibility in CAN network modules
3. Symptoms You Will Notice
- Adaptive cruise control inoperative or disabled
- Automatic emergency braking not functioning
- Distance-keeping feature unavailable
- ACC warning light or message on the dashboard
4. Step-by-Step Diagnosis
Scan for all stored codes and freeze frame data to confirm U043C and related codes
Visually inspect the right front distance sensor for contamination, damage, or misalignment
Check the wiring and connectors for corrosion, breaks, or poor connections
Perform a CAN bus integrity test to rule out network communication issues
If wiring and sensor appear okay, test the sensor output with a diagnostic tool or replace with a known-good unit
If problem persists, check for software updates for the ACC module and PCM
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, but with reduced safety features. The vehicle remains drivable, but adaptive cruise control and automatic braking will be disabled. Drive cautiously and have the issue diagnosed soon.
How much does it cost to fix?▼
Costs vary widely: cleaning or realigning the sensor may be $100-$200; replacing a sensor can be $500-$1,200; module replacement or reprogramming could exceed $1,500. Diagnosis typically runs $100-$200.