DTC B0021-1A: Left Curtain Deployment Control 1 - Circuit resistance below threshold: Action

WARNING: This page is about a different car, the 2018 Land Rover Discovery and 2017 Land Rover Discovery. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Do not measure the resistance of a deployable device using any other method than that described below

NOTE:

A shorting bar inside the connector (deployable device side) intentionally creates a short circuit until the wiring harness connector is installed AND the connector plunger is engaged
Airbag resistance should be 1.70 ohms to 2.30 ohms between -40 deg C to +85 deg C

Using the Jaguar Land Rover approved diagnostic equipment, check datalogger signal - Deployment Control 6 Resistance (0x5B09). If the resistance is too low, disconnect and reconnect the left side air curtain connector, ensuring that the connector plunger is correctly engaged. Clear the DTCs and retest
Refer to the appropriate SYSTEM WIRING DIAGRAMS information and check the left side air curtain circuit for short circuit between power and ground. Clear the DTCs and retest. If the fault persists, install a new wiring harness as necessary
If no wiring harness fault exists, using the Jaguar Land Rover approved diagnostic equipment, clear the DTCs and retest