P1630
Theft Deterrent Learn Mode Active
What it means
P1630. Theft Deterrent Learn Mode Active. This Chevy-enhanced code applies to Silverado, Sierra, Impala, Malibu, Cavalier, Alero.
Findings, check these first
- Uncompleted Passlock relearn after BCM or PCM replacement
- Using an unprogrammed key or new lock cylinder without performing the learn
- Low battery voltage interrupting the 30-minute relearn cycle
- Failed BCM unable to exit learn mode
Standard procedure
- Complete the full 30-minute Passlock relearn (three 10-minute key-on cycles) with a charged battery
- Keep a battery maintainer connected during the relearn so voltage stays above 12 volts
- Verify the security lamp state at each step of the relearn procedure
- Diagnose BCM powers and grounds with a Tech2/GDS2 scan tool if learn mode never exits
Look up another code
Press / to jump to the box. Chevy-enhanced powertrain, body, chassis and network codes.
Sources and review
Review: checked against the recorded source material.
- OBDII Code P1630 CHEVROLET - Theft Deterrent Learn Mode Active | Engine-Codes.com
archived reference page (engine-codes.com via Wayback Machine)
Supports: code identity and Chevrolet application
Fetched directly. Exact title match. Model and year fitment remain curator claims.
Last updated 2026-09-13.
Report a correction for P1630. Include your vehicle, the issue and a source if you have one.
This fault sits in the GM theft deterrent system. The GM security codes and Passlock relearn guide covers the families and the relearn cycles.