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Home / DTC / B1A56 — Failure in the driver seat slide control relay Driver seat backrest relay control failure

B1A56 — Failure in the driver seat slide control relay Driver seat backrest relay control failure

Detailed page for trouble code B1A56.

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Code

B1A56

LAND ROVER B — Body

Failure in the driver seat slide control relay Driver seat backrest relay control failure

Brand: LAND ROVER
Type: B — Body
AI status
Completed
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Page language: EN

Causes

  • Defective driver seat slide or backrest relay
  • Open, shorted or corroded wiring/connectors in the relay or seat harness
  • Poor or missing ground at seat control or relay
  • Blown fuse or poor fuse connection supplying the relay
  • Faulty seat control module (SCM) or body control module commanding the relay
  • Seized/overloaded seat motor or mechanical obstruction causing overload

Symptoms

  • Driver seat will not slide forward/back or backrest will not adjust
  • Intermittent or no response from seat switch inputs
  • Steering/seat position memory may not operate correctly
  • Dash message or warning related to seat adjustment
  • Associated seat motor noise absence or abnormal motor behavior
  • Related DTCs present for seat motor, switches, or communication

What to check

  • Read DTCs and freeze-frame data with a capable scan tool; note related seat or CAN codes
  • Visually inspect seat relay, fuse(s) and fuse holder for damage or corrosion
  • Operate seat controls while watching live data and relay activation status
  • Check supply voltage to relay coil and contacts (battery voltage ~11.5–14.5 V)
  • Check continuity to ground at relay and seat control module (low ohms)
  • Inspect wiring and connectors along seat harness for pin corrosion, bent pins, damaged insulation or water ingress

Signal parameters

  • Relay coil/command voltage: approx. battery voltage (activated) ~11.5–14.5 V
  • Relay control signal from seat control module: switched/grounded or logic-level command (verify with scan tool or scope)
  • Ground resistance to chassis:
  • Seat motor current draw: should be below manufacturer peak (typical low tens of amps for short durations) and not continuous high draw
  • Seat position sensor/feedback voltage: typical 0–5 V range depending on sensor type
  • CAN/CAN-FD messages: presence and correct message rates for seat/BCM/SCM communications

Diagnostic algorithm

  1. Connect a diagnostic scan tool, record B1A56 and any related codes, check freeze-frame and live-data while attempting seat movement.
  2. Verify fuses for seat circuits and inspect the relay physically; replace fuse or relay if blown/damaged and re-test.
  3. With ignition on, operate the seat control and confirm whether the relay receives a command (use multimeter or scope to monitor relay coil terminal).
  4. Check supply voltage at the relay power terminal and verify a good ground at relay/chassis while commanding the circuit. Repair poor supply/ground as required.
  5. Inspect connectors and wiring from relay to seat control module and seat motors; repair any damaged wires or corroded pins. Wiggle-test connectors while observing live data to detect intermittent faults.
  6. Measure motor current during operation to detect mechanical seizure or motor overload. If motor draws excessive current, diagnose motor/mechanical binding before replacing modules.
  7. If wiring, power, ground and relay test good, use a known-good relay or bench-test the relay. If relay works and problem persists, test/replace the seat control module following manufacturer programming procedures.
  8. If communications errors are present, diagnose CAN bus wiring, termination and related modules.
  9. After repairs, clear codes, retest seat operation through full range and confirm no recurrence of B1A56. Record final test results.

Likely causes

  • Faulty seat slide/backrest relay
  • Corroded/loose connector at the seat relay or seat control module
  • Blown fuse or loss of supply voltage to relay coil
  • Open/short in the relay control wiring or poor ground
  • Faulty seat control module after wiring and relay checked

Fault status

⚠️ Status
Driver seat slide/backrest relay control failure detected — relay not being commanded or not responding; possible relay, wiring, fuse, ground or seat control module fault.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0 - 3.0 hours

Similar codes

B1A55 B1A57 B1A58 B1A5A B1A50
320

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