Is APS_W166 the same as APS-W166?

Yes. APS_W166, APS W166, and APS-W166 are alternate spellings of the same Tesla alert code. Also written as: APS-W166, APS_W166, APS W166, APS_w166_TurboA_SMSLockStepErr, aps_w166_turboa_smslocksteperr.

What symptoms can APS-W166 cause?

Autopilot System alert: Side Collision Warning Unavailable Warns if forward radar fails to receive valid vehicle signals from APS Forward radar Camera or sensor obstruction notification on the touchscreen Autopilot features greyed out in the drive settings menu

What should I check for APS-W166?

1. Check all cameras and sensors for dirt, ice, or obstructions — clean if needed 2. Reboot the vehicle 3. Check for OTA updates (Autopilot improvements are frequently delivered OTA) 4. Schedule service if Autopilot remains unavailable after cleaning and rebooting

Is it safe to drive with APS-W166?

🟡 Check the vehicle display for drive or charge restrictions and schedule service promptly.

TESLA Warning

APS-W166

APS_w166_TurboA_SMSLockStepErr

Also written as APS_W166 / APS W166 / APS_w166_TurboA_SMSLockStepErr / aps_w166_turboa_smslocksteperr

System

APS

Autopilot System

Type

Warning

Why does the exact Tesla alert ID matter?

Record the exact alert ID, including underscores, suffixes, and companion alerts. Tesla alerts that look similar can point to different modules, timestamps, and service procedures.

What does APS-W166 mean?

Tesla warning code in the Autopilot System (APS) module. Side Collision Warning Unavailable Warns if forward radar fails to receive valid vehicle signals from APS Forward radar reports that it is receiving invalid vehicle signals from APS Forward radar starts receiving valid vehicle signals from APS APS doesnt receive SC msgs for more than 10 cycles APS starts receiving msgs from SC Warns if APS detects GPS receiver is in a bad state APS detects communication or antenna issues with GPS receiver Navigation and Autosteer will be broken

Original Description

Side Collision Warning Unavailable Warns if forward radar fails to receive valid vehicle signals from APS Forward radar reports that it is receiving invalid vehicle signals from APS Forward radar starts receiving valid vehicle signals from APS APS doesnt receive SC msgs for more than 10 cycles APS starts receiving msgs from SC Warns if APS detects GPS receiver is in a bad state APS detects communication or antenna issues with GPS receiver Navigation and Autosteer will be broken

Affected Tesla Models

Model SModel XModel 3Model Y

What You May Notice

Autopilot System alert: Side Collision Warning Unavailable Warns if forward radar fails to receive valid vehicle signals from APS Forward radar
Camera or sensor obstruction notification on the touchscreen
Autopilot features greyed out in the drive settings menu

How to Diagnose and Resolve

1 Check all cameras and sensors for dirt, ice, or obstructions — clean if needed
2 Reboot the vehicle
3 Check for OTA updates (Autopilot improvements are frequently delivered OTA)
4 Schedule service if Autopilot remains unavailable after cleaning and rebooting

Severity Notes

APS-W166 is a Warning in the Autopilot System system. Schedule service soon. Monitor your vehicle for additional warnings.

Other APS Codes

APS_w002 APS_w003 APS_w004 APS_w005 APS_w006 APS_w007 APS_w008 APS_w009

View all APS codes →