Chevrolet U1152: No Communication With HVAC Control Module

Is your scanner showing Chevrolet U1152?
No worries. We'll show you what it means and how to deal with it.

Presented by

Randy Worner

00:00/00:00

Chevrolet U1152: No Communication With HVAC Control Module

OVERVIEW

Severity

Medium

DIY Difficulty Level

Intermediate

Repair Cost

$75-$200

Can I Still Drive?

Yes

What Does The Chevrolet U1152 Code Mean?

Key on, and a message from a learned ID number was not detected for the five seconds. Modules on the Class 2 circuit monitor for data communications during vehicle operation. When a module receives a message for critical data, the module records the identification number of the module which sent the message for the state of health monitoring/node alive messages. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that module node alive message. Each module on the class 2 serial data circuit is required to send a Node Alive message every 2 seconds. When no message is detected from a learned identification number for 5 seconds, a Diagnostic Trouble Code (DTC) U1152 is set.