U2099 — High Speed Communication Enable Circuit

Generic OBD2

Generic OBD2: U2099

High Speed Communication Enable Circuit

Reference namespace: obd2
Source revision: legacy-2.2.20

Generic OBD2 definition; confirm the protocol and vehicle-specific service information.

Manufacturer reference family

GM: U2099

High Speed Communication Enable Circuit Short to Battery; High Speed Communication Enable Circuit Short to Ground; High Speed Communication Enable Circuit Open; High Speed Communication Enable Circuit Not Plausible

Reference namespace: gm
Source revision: legacy-oem-dtc-r2-20260924

Reference family assigned by the production catalog. An entry in this family is not proof of a fault or ECU support on every listed vehicle.

What should I check before using this definition?

Keep the full code, module, status and freeze-frame data. Confirm the vehicle’s make, model, year and current manufacturer service information before choosing a repair. This entry does not identify a failed part by itself.

Organize a scan report or recording

Source and applicability

OBD Lens production library legacy-owner-2026-11-02-v84-evidence. This is a scoped technical reference, not a scan of your car. A catalog relationship does not certify that every ECU, year or engine returns the same signal or code definition.

Read the reference method

What does U2099 mean?

High Speed Communication Enable Circuit. 2 reference families define this identifier: GM, Generic OBD2.

Is U2099 a generic or manufacturer-specific code?

Check the reference scope shown above for this identifier.

Can U2099 tell me which part has failed?

This entry does not identify a failed part by itself. Confirm the vehicle’s make, model, year and current manufacturer service information before choosing a repair.