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Home / DTC / B12B1 — Washer relay and park wiper cleaner

B12B1 — Washer relay and park wiper cleaner

Detailed page for trouble code B12B1.

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Code

B12B1

LAND ROVER B — Body

Washer relay and park wiper cleaner

Brand: LAND ROVER
Type: B — Body
Views: UK: 8 EN: 15 RU: 10
AI status
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Page language: EN

Causes

  • Blown fuse for washer pump/relay circuit
  • Faulty washer relay (stuck, no coil activation or no contact closure)
  • Open or short in wiring between relay, washer pump and body control module (BCM)
  • Corroded or loose connector at pump, relay or ground
  • Washer pump motor fault (high/low current, seized)
  • Faulty wiper park switch or park position sensor

Symptoms

  • Washer pump does not operate when activated
  • Wipers fail to return to park or park function operates incorrectly
  • Intermittent washer or wiper cleaner operation
  • Washer warning message or lamp may be displayed
  • Fault code stored in body/BCM with related washer/wiper functions disabled

What to check

  • Read and record freeze frame and live data with an OEM-capable scan tool; note any related body module faults
  • Visual inspection of fuses, relay, wiring harness, and connectors for corrosion, water ingress or damage
  • Check fused battery feed and ground at relay and pump connectors
  • Confirm relay clicks when washer/wiper is commanded; test relay coil and contacts
  • Measure voltage at pump connector while activating washer command (expect battery voltage ~11–14 V)
  • Measure current draw of pump if accessible (compare to known-good spec or expected running current)

Signal parameters

  • Control signal: switched battery voltage present at relay output when washer/wiper command issued (approx. 11–14 V)
  • Relay coil control: driver from BCM should show activation signal (either +12 V or switched ground depending on vehicle design)
  • Pump current draw: measurable motor current when powered (compare to manufacturer spec; significant deviation indicates motor fault)
  • Resistance: low resistance (near 0 Ω) between relay output and pump positive when relay closed; low resistance to ground at pump ground terminal
  • Park switch: park position signal should change state when wipers reach park (logic level signal on dedicated circuit)

Diagnostic algorithm

  1. Use a scan tool to read all stored codes and live data from the body/BCM. Note any related codes and clear then attempt to re-create the fault.
  2. Perform a visual inspection of the washer pump, relay, fuse(s) and wiring for obvious damage, disconnected or corroded connectors and water ingress.
  3. Verify fuse continuity and replace blown fuse if found. Re-test system — if fuse blows again, investigate short to power/ground.
  4. Operate the washer/wiper command while listening for relay click. If relay does not click, check for control voltage at the relay coil connector with command active.
  5. With the relay removed, check relay coil resistance and swap the relay with a known-good same-type relay if available to confirm relay function.
  6. Backprobe the relay output to measure voltage at the pump connector while commanding the washer. If battery voltage is present at relay but not at pump, inspect wiring/connector between relay and pump.
  7. If no voltage at relay output, trace the control feed from the BCM: check harness continuity, connector pins and ground references. Repair any wiring faults.
  8. If voltage is present at pump connector but pump does not run, carefully apply battery voltage directly to pump (observe polarity) to confirm motor operation. Replace pump if it does not run or draws excessive current.
  9. If park-related behavior is the issue, check the wiper park switch/sensor inputs and wiper motor park switch, verify correct feedback to BCM and repair/replace as needed.
  10. After repairs, clear codes and verify normal operation through multiple cycles. If fault persists and wiring/actuator tests are correct, consider BCM module fault and consult manufacturer diagnostics before replacement.

Likely causes

  • Failed or intermittent washer pump relay
  • Open circuit or poor ground to the washer pump
  • Connector corrosion at pump or relay
  • Washer pump motor failure or seized impeller
  • Wiper park switch not signalling park position (affecting park/cleaner logic)

Fault status

⚠️ Status
Washer relay / park wiper cleaner circuit — electrical fault detected (relay, wiring, pump or park switch fault).
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-1.5 hours

Similar codes

B12B0 B12B2 B12A1 B12C1 B12D1
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