What does U1500 mean on a Chevy?

U1500. Lost Communication With Vehicle Communication Interface Module. Applies to Impala, Silverado, Sierra, Tahoe, Malibu.

What causes U1500 on a Chevy?

Internal failure of the OnStar vehicle communication interface module (VCIM) Obsolete analog or 2G cellular hardware continuously searching for a dead network Blown INFO or ONSTAR fuse cutting power to the module Corroded VCIM connector or Class 2 serial data circuit fault

How do I fix U1500 on a Chevy?

Confirm U1500 is current and check for a red OnStar LED or Phone Unavailable message Inspect the INFO or ONSTAR fuse before diagnosing further Perform a parasitic draw test; a draw of several hundred milliamps points to a VCIM that will not sleep Disconnect the VCIM to confirm it is the drain source; leaving it unplugged is an accepted fix since the network is obsolete Replace the module only if OnStar or Bluetooth function must be restored, then verify the code clears

Code

U1500

Lost Communication With Vehicle Communication Interface Module

Category: Network Communications
Severity: Check Engine Light
Applies to: Impala, Silverado, Sierra, Tahoe, Malibu
Related: No single generic twin. See OBD Codes List

What it means

U1500. Lost Communication With Vehicle Communication Interface Module. This Chevy-enhanced code applies to Impala, Silverado, Sierra, Tahoe, Malibu.

Findings, check these first

Internal failure of the OnStar vehicle communication interface module (VCIM)
Obsolete analog or 2G cellular hardware continuously searching for a dead network
Blown INFO or ONSTAR fuse cutting power to the module
Corroded VCIM connector or Class 2 serial data circuit fault

Standard procedure

Confirm U1500 is current and check for a red OnStar LED or Phone Unavailable message
Inspect the INFO or ONSTAR fuse before diagnosing further
Perform a parasitic draw test; a draw of several hundred milliamps points to a VCIM that will not sleep
Disconnect the VCIM to confirm it is the drain source; leaving it unplugged is an accepted fix since the network is obsolete
Replace the module only if OnStar or Bluetooth function must be restored, then verify the code clears

Look up another code

Press / to jump to the box. Chevy-enhanced powertrain, body, chassis and network codes.

Sources and review

Review: no source links are recorded for this entry.

Last updated 2026-09-19.

Report a correction for U1500. Include your vehicle, the issue and a source if you have one.