Mobileye Error ER-20 — Speed Signal Not Detected

What Does This Error Mean?

ER-20 on a Mobileye unit means the system is not receiving a vehicle speed signal. Mobileye uses the vehicle's speed data to calibrate warning timing — at low speed it suppresses unnecessary alerts, and at highway speed it activates headway monitoring. Without a speed signal, several warning features are degraded or disabled.

Affected Models

Mobileye 6 Series
Mobileye 8 Connect
Mobileye Shield+
Mobileye 630
Mobileye 650

Common Causes

CAN-bus speed signal wire not connected or disconnected during installation
Speed signal wire damaged — cut, pinched, or corroded
Vehicle CAN-bus protocol not compatible with the configured Mobileye speed input
Incorrect speed input configuration in the Mobileye settings for this vehicle type
GPS speed mode not enabled as fallback — some models can use GPS speed when CAN is unavailable

How to Fix It

Check whether ER-20 appeared suddenly or was present from the original installation.

If ER-20 appeared from day one, the speed signal was never correctly connected during installation. Contact the Mobileye installer — this is their installation error.
Check if ER-20 appeared after electrical work on the vehicle.

If ER-20 appeared after a workshop visit, battery replacement, or accessory installation, a technician may have disturbed the Mobileye speed signal wire.
Check whether GPS speed mode is available on your Mobileye model.

Some Mobileye models (particularly Mobileye 8 Connect) can use GPS-derived speed as a fallback when CAN-bus speed is unavailable. An authorised installer can configure this in the system settings.
Contact a Mobileye authorised installer for speed signal re-wiring.

The technician will locate the correct CAN-bus speed wire for your vehicle and reconnect or replace the signal wire.

When to Call a Professional

ER-20 is typically an installation wiring issue and requires a Mobileye installer to diagnose and correct.

Frequently Asked Questions

Does ER-20 mean the collision warning system is completely disabled?

Not completely — the vision-based forward collision warning still operates using camera data. However, speed-dependent features such as headway monitoring distance calculation, intelligent high beam control thresholds, and PCW sensitivity calibration are degraded without accurate speed data. Fix ER-20 to restore full system functionality.

Can Mobileye work without a CAN-bus speed connection?

On models that support GPS speed, yes — an installer can configure GPS as the speed source. On models that require CAN-bus speed, ER-20 will persist until the wiring is corrected.