P155D 2015 Chevrolet Silverado Code - Hill Descent Control Message Counter Incorrect

P155D indicates an issue with the Hill Descent Control system, specifically related to an incorrect message counter, which may prevent the system from functioning properly.

The most common symptoms include the Hill Descent Control (HDC) system not engaging, a warning light on the dashboard, and possible reduced functionality of other stability or traction features.

This code is typically caused by a communication issue between the Hill Descent Control module and other control modules, such as the powertrain control module (PCM), often due to a software glitch or faulty wiring.

While it may not cause immediate damage, the Hill Descent Control system will not operate as intended, which could compromise safety when driving on steep descents.

A technician will use a scan tool to check for related codes, inspect the communication lines between modules, verify proper operation of the HDC system, and look for any wiring or connector issues.

Fixes may include reprogramming or updating the software in the affected modules, repairing damaged wiring or connections, or replacing a faulty Hill Descent Control module.

Clearing the code without addressing the underlying issue may temporarily turn off the warning, but the problem is likely to return and affect the HDC system.

It depends on the vehicle’s age, mileage, and warranty status. Check with your dealer to see if the issue is covered under the powertrain or emissions warranty.

A weak or failing battery can potentially cause communication errors between modules, so it’s worth checking the battery and charging system as part of the diagnostic process.

Repair costs vary depending on the root cause but may range from $100 for minor wiring repairs to $500 or more for module reprogramming or replacement.