IO4 (RPO IO4 — Base 4.2-Inch Color Display Infotainment)

RPO Codes

The GM RPO code for the base 4.2-inch color display infotainment configuration found on entry-level trims of 2014–2016 GM trucks and SUVs.

IO4 is the GM Regular Production Option (RPO) code for the base 4.2-inch color display infotainment configuration. It is the entry-level radio package on K2-era trucks and SUVs (2014–2016) — a smaller color display in the center stack, paired with physical buttons and a separate ACM radio module. IO4 does not have the 8-inch touchscreen used on IO5 and IO6 vehicles.

What IO4 includes:

  • 4.2-inch color driver information display in the center stack
  • AM/FM/SiriusXM radio with physical preset and tuning buttons
  • Bluetooth hands-free calling and audio streaming
  • USB and AUX inputs
  • Basic vehicle settings display

What IO4 does NOT include:

  • 8-inch touchscreen (that’s IO5/IO6)
  • Apple CarPlay or Android Auto (added on HMI 2.5 with the 8-inch screen)
  • Embedded factory navigation (that’s IO6)
  • App Shop (that’s CSM)

The most common upgrade for IO4 vehicles is the 4-inch to 8-inch screen upgrade, which converts the vehicle from IO4 to IO5 or IO6 — adding the 8-inch touchscreen, the HMI module, and full MyLink/IntelliLink functionality including CarPlay/Android Auto (on 2016 vehicles). The upgrade requires HMI, screen, harness, and bezel components plus VIN programming to enable the new RPO content.

IO4 vehicles are typically the base or fleet trim levels: 2014–2016 Silverado/Sierra WT or LS, base 2015–2016 Tahoe/Suburban/Yukon, base 2015–2016 Yukon XL, and similar entry trims. The configuration was discontinued as HMI 2.5 standardized on the 8-inch screen across the lineup from 2017 onward.

Vehicle Applicability

Base and fleet trims of 2014–2016 K2-era GM trucks and SUVs — Silverado, Sierra, Tahoe, Suburban, Yukon, Yukon XL. The 4-to-8-inch screen upgrade is offered by WAMS for 2014–2016 vehicles.

Also known as: IO4, RPO IO4, base radio, 4.2 inch display, 4-inch screen

Related Terms

  • IO5 — The GM RPO code for the non-navigation HMI 2.0/2.5 infotainment configuration found on most 2014–2019 GM vehicles.
  • IO6 — The GM RPO code for the HMI infotainment configuration with embedded factory navigation, found on premium-trim 2014–2019 GM vehicles.
  • HMI — The primary infotainment computer in most 2013–2020 GM vehicles with MyLink, IntelliLink, or first-generation CUE.
  • ACM — The radio/head-unit module in GM HMI-based infotainment systems containing the AM/FM/HD/SiriusXM tuner and base amplification.
  • MyLink — Chevrolet's branded infotainment interface, used on HMI-based vehicles from 2013 onward.
  • IntelliLink — GMC's and Buick's branded infotainment interface, used on HMI-based vehicles from 2013 onward.
  • RPO — GM's three-character codes identifying every factory-installed option, package, and feature on a vehicle. Critical for module matching and parts ordering.
  • SPID label — The physical sticker on a GM vehicle that lists all of its RPO option codes. Typically located in the glove box, trunk floor, or door jamb.
  • GM Truck and SUV Platform Lineage — Reference timeline of GM's full-size truck/SUV vehicle platforms — GMT900, K2/K2XX, T1/T1XX — and the Alpha compact RWD platform. Critical for module compatibility.

Learn More

Shop Related