Drive By Wire (DBW)

Drive‑By‑Wire (DBW): an electric motor controls the throttle blades. The gas pedal is a sensor that sends input to the TAC (Throttle Actuator Control) module. The TAC reads the pedal, tells the throttle motor how far to open, and communicates with the PCM. If TAC and PCM don’t communicate, the throttle won’t operate and PCM fault codes will set.

DBW timeline:

  • 1997: Corvette

  • ~2001: some higher‑end SUVs

  • 2003: all pickup trucks

  • 2004: some Express vans (usually AWD with traction control)

  • 2007: all vans DBW (most vans used mechanical throttle through 2006)

When buying a motor from a salvage yard, also get the gas pedal assembly, TAC module, and the short pedal‑to‑TAC harness (it passes through the firewall with a rubber grommet). The rest of the wiring is in the engine harness.

Typical wiring (2004 C/K 4.8/5.3/6.0) and DBW differences:

  • DBW introduced to trucks around 2000 (Corvette in 1997)

  • 2000–2002 throttle body: two connectors — 2‑pin passenger, 6‑pin driver

  • 2003+ throttle body: single 8‑pin connector on passenger side

  • TAC modules:

    • 1999–2002: all‑plastic (interchangeable)

    • 2003–2006 (and 2007 Classic): plastic with metal mounting bracket (interchangeable)

GM TAC module 1999-2002 front view — all-plastic housing

TAC MODULE 99-02

GM TAC module 2003-2007 with metal mounting bracket

TAC MODULE 2003-2007

GM 2003-2005 drive by wire accelerator pedal assembly

2003-05 Pedal

GM TAC module 1999-2002 connector side view
GM TAC module 2003-2007 connector side view
GM DBW pedal-to-TAC wiring harness with firewall grommet

Pedal Harness

GM 2006-2007 classic body style drive by wire accelerator pedal assembly

2006-07 Pedal (Classic Body Style Trucks)