B1622

Wiper Rear Low Limit Input Circuit Short To Ground

Body Chassis/Safety Wiper System 🟢 Low — Fix at next service ✅ Safe to Drive
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What This Actually Means

In plain language — no jargon

The rear wiper motor circuit is detecting a short to ground, meaning the electrical signal is taking an unintended path to ground instead of following the proper circuit. It's like water leaking out of a pipe before reaching its destination.

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Symptoms You May Notice

3 known symptoms for this code
Rear wiper inoperative or stuck in one position
Rear wiper moves erratically or continuously
Dashboard wiper control unresponsive
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors the rear wiper low-limit position sensor signal voltage to detect when the wiper blade reaches its park position. A short-to-ground condition pulls the voltage signal to 0V, preventing the ECU from recognizing the normal operational state. The module expects a voltage above a minimum threshold; when it detects continuity to ground, it sets the fault code.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Rear Wiper Position Signal 2.5-4.5V <0.5V (shorted to ground)
Circuit Resistance >10 kΩ to ground <1 kΩ to ground
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Rear wiper connector and wiring harness
Inspect the connector at the rear wiper motor for corrosion, moisture, or loose pins causing a ground short.
2
Rear wiper motor assembly
Replace the motor if internal wiring is damaged or insulation is compromised.
3
Wiper control relay or module
Replace the rear wiper relay if circuit shorts persist after wiring inspection.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code B1622 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.

Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.
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How to Clear Code B1622

What happens after you fix the fault

Once the fault is repaired, B1622 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.

The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.

✅ Safe to Clear When
  • Fault has been diagnosed and repaired
  • You want to confirm the repair worked
  • Code appeared after a sensor was cleaned
⚠️ Do Not Clear When
  • Preparing for an emissions/PUC test
  • Root cause is still undiagnosed
  • Check engine light is flashing
Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.