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2017 CT6 Platinum: Adaptive Cruise Control 'Sensor Blocked' Error

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Mike T. · rep 0 · May 25, 2:53 AM · 1 replies · solved · Question

Vehicle: 2017 Cadillac CT6 Platinum

Hi everyone,

I'm facing a frustrating problem with my 2017 Cadillac CT6 Platinum. The Adaptive Cruise Control (ACC) system keeps throwing a 'Sensor Blocked' error message on the dash, even when the front of the car is perfectly clean and clear. This happens frequently, sometimes within minutes of starting a drive, and it disables the ACC and sometimes even the regular cruise control.

I've thoroughly cleaned the front grille and the area around the Cadillac emblem where I believe the radar sensor is located. There's no visible damage, dirt, or ice. It just seems to randomly decide it's blocked. It's really impacting my long-distance driving comfort.

Has anyone else experienced this with their CT6? Is it a common sensor failure, a wiring issue, or something else entirely? Any advice or insights would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 2:53 AM

0

ClearTheCode admin answer:

  1. Understand the ACC System: The Adaptive Cruise Control (ACC) system in your 2017 Cadillac CT6 Platinum uses a radar sensor, typically located behind the front grille or emblem, to detect vehicles ahead and maintain a set distance. The 'Sensor Blocked' message indicates that the system believes its view is obstructed, preventing it from functioning safely.

  2. Common Causes for 'Sensor Blocked' Error (when clear):

    • Radar Sensor Malfunction: The sensor itself can fail internally, leading to incorrect readings or an inability to 'see' clearly, even when unobstructed. This could be due to internal electronic component failure.
    • Misalignment: Even a minor bump or vibration can slightly shift the radar sensor's alignment. These sensors are highly sensitive and require precise calibration. A misaligned sensor will 'see' incorrectly.
    • Wiring/Connector Issues: Damaged, corroded, or loose wiring harnesses and connectors leading to the radar sensor or its control module can cause intermittent communication errors, mimicking an obstruction.
    • Module Failure: The ACC control module (which processes the sensor data) could have an internal fault.
    • Software Glitch: Less common, but a software bug within the ACC system or related body control module could cause erroneous 'blocked' readings.
    • Interference (Rare): Very strong external electromagnetic interference could theoretically disrupt the radar, but this is highly unlikely to be the primary cause.

  3. Troubleshooting Steps:

    • Thorough Visual Inspection: Double-check the entire front bumper and grille area for any subtle impacts, warping, or anything that might be subtly obstructing the sensor. Ensure the emblem itself is securely fastened and not loose.
    • Battery Reset (Temporary): Disconnecting the battery for 15-30 minutes can sometimes clear minor electronic glitches, but it's unlikely to fix a persistent hardware or alignment issue.
    • Diagnostic Scan: A standard OBD-II scanner might not pick up specific ACC codes, as they are often manufacturer-specific. However, a more advanced diagnostic tool (like those used by dealerships or specialized shops) can communicate with the ACC module and retrieve specific Diagnostic Trouble Codes (DTCs) related to sensor performance, communication errors (e.g., U0xxx codes), or module faults.

  4. When to See a Shop:

    • Promptly: Since ACC is a safety and convenience feature, it's best to have it diagnosed by a professional as soon as possible. Driving without functioning cruise control can be inconvenient, and a faulty sensor could potentially impact other ADAS features.
    • A Cadillac dealership or a reputable independent shop with advanced diagnostic equipment will be able to:
      • Scan for specific ACC module codes.
      • Perform a radar sensor calibration. This is a crucial step if misalignment is suspected and requires specialized tools.
      • Test sensor output and wiring continuity.
      • Determine if the radar sensor or the ACC control module needs replacement. Sensor replacement will almost certainly require recalibration.
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