B1829

Wiper Rear High 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 circuit is detecting a short to ground, meaning the electrical signal is leaking to the chassis instead of flowing properly. It's like a water hose with a hole in it—the signal can't reach its destination.

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Symptoms You May Notice

3 known symptoms for this code
Rear wiper does not operate or operates intermittently
Rear wiper stuck in one position
B1829 fault code stored in ECU memory
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors the voltage signal from the rear wiper motor control circuit at its high-limit position feedback. When the circuit shorts to ground, the voltage drops to near 0V instead of the expected threshold, triggering the fault. The ECU expects a specific voltage range to confirm proper motor positioning.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Rear wiper high limit voltage 10.5-12.5V or signal present Below 2V or 0V (short to ground)
Circuit resistance to ground Greater than 10kΩ Less than 1kΩ
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Wiper relay connector
Inspect and reseat the rear wiper relay connector in the fuse box to eliminate poor contact.
2
Wiper harness connectors
Check all wiring connectors at the rear wiper motor and switch for corrosion or damage and clean as needed.
3
Rear wiper motor assembly
Replace the rear wiper motor if internal windings are shorted or connectors are damaged beyond cleaning.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code B1829 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 B1829

What happens after you fix the fault

Once the fault is repaired, B1829 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.