B1C73

Code

LAND ROVER B — Body

Relay coil circuit Superlock

Brand: LAND ROVER

Type: B — Body

Views: UK: 14 EN: 18 RU: 12

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Faulty Superlock relay (coil open or shorted)
Blown or corroded fuse supplying the relay
Open, shorted or damaged wiring in the relay coil circuit
Poor or corroded connector or terminal at the relay socket
Bad ground connection for relay coil or BCM
Water ingress or corrosion in harness or connector

Symptoms

Superlock (deadlock) function does not operate or is intermittent
Central locking behaves inconsistently (locks but not deadlocks)
DTC stored and possibly lamp/message related to locking system
Blown fuse on locking circuit after repeated attempts
Clicking/noise absence from relay when commanded

What to check

Retrieve all stored codes and freeze-frame data with a diagnostic scanner; note related body/locking codes
Visually inspect Superlock relay, fuse(s), relay socket and harness for corrosion, damage or water ingress
Verify correct fuse(s) and replace if blown; inspect fuse holder terminals
With key/diagnostic tool, command Superlock while probing: check 12 V supply at relay fuse pin and coil supply pin
Measure voltage on control/driver pin at relay socket while commanding Superlock; it should change (typically 0 V to ~12 V or ground switching depending on design)
Measure coil resistance of removed relay and compare to specification (see signal_params)

Signal parameters

Relay coil resistance (typical): 70–200 ohms (verify with manufacturer data)
Coil supply voltage when inactive: battery voltage (~11–14 V depending on battery/ignition state)
Coil voltage when commanded: ~11–14 V (or switching to ground depending on relay driver type)
Typical coil current: 60–170 mA (dependent on coil resistance)
Command duration: brief pulse when locking command is sent; may vary by vehicle logic

Diagnostic algorithm

Connect a capable diagnostic tool. Read and record DTCs, freeze frame and module data. Note any related body/locking codes.
Visually inspect the Superlock relay, associated fuses, wiring harness and connectors for corrosion, damage or water ingress. Repair obvious issues.
With ignition in required position and vehicle safe, command Superlock while monitoring the relay socket with a multimeter: verify constant 12 V supply at the fused feed, and that the control pin changes when the command is issued.
Remove the relay and measure coil resistance on the relay itself. Compare to specification. Replace relay if coil open or out of range.
If relay measured OK, probe the relay socket: check supply voltage present at fuse feed, check control/driver voltage response to commands and verify ground continuity. Repair any open/short connections.
Perform a wiggle/test drive or actuate the circuit repeatedly to try to reproduce intermittent faults. Repair broken wires, terminals or corroded pins found.
If wiring, connectors and relay are confirmed good but the fault persists, consult wiring diagrams and test the BCM output driver for correct operation. Replace or reprogram BCM only after confirming driver failure and following manufacturer procedures.
Clear DTCs, retest Superlock operation and monitor for reoccurrence. Confirm full system functionality.

Likely causes

Corroded relay socket or poor pin contact
Open or intermittent supply voltage to relay coil
Open or shorted control/ground wire to the BCM
Failed relay coil
BCM output driver fault (less common)

Fault status

⚠️ Status

Relay coil circuit fault — Superlock relay coil voltage out of range (open/short/poor connection) detected by BCM.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

Repair manuals

Manual library for LAND ROVER

320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

Send to email