C1704

Right Rear Sensor Circuit Fault

Chassis Chassis/Safety ABS/Stability Control 🔴 Serious — Stop or limit driving 🚫 Do Not Drive
💬

What This Actually Means

In plain language — no jargon

Your vehicle's right rear wheel speed sensor isn't sending a proper signal to the ABS/stability control system. It's like a missing speed report from one wheel, so the system can't tell if that wheel is slipping.

⚡

Symptoms You May Notice

3 known symptoms for this code
ABS warning light illuminated on dashboard
Traction control or stability control disabled or warning light active
Possible pulsing brake pedal during emergency braking
🔬

How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECM monitors AC voltage output from the right rear wheel speed sensor as the wheel rotates. The sensor should produce a clean sinusoidal signal with specific frequency and amplitude that correlates to wheel speed. If voltage is absent, too low, erratic, or out of sync with other wheels, the fault is triggered.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Sensor Signal Voltage 0.5-2.0V AC at operating speed Below 0.2V AC or open circuit
Signal Frequency Variance Within 10% of opposite wheel Deviation exceeds 10% or no signal
🔧

Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Wheel speed sensor connector
Clean corroded contacts at the right rear sensor connector with electrical contact cleaner and reseat firmly.
2
Wheel speed sensor wiring harness
Inspect the wiring from sensor to ABS module for pinches, cuts, or corrosion and repair or replace damaged sections.
3
Right rear wheel speed sensor
Remove the sensor from the wheel hub, clean the magnetic tip, check air gap (typically 0.3-1.0mm), and reinstall or replace if damaged.
⚠️

When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code C1704 is classified as a serious fault. If your check engine light is flashing — not just steady — pull over safely and do not continue driving. A flashing CEL indicates an active misfire or critical failure that can cause catalytic converter damage within minutes or permanent engine harm within miles. Contact a certified mechanic immediately. Do not attempt roadside repairs on high-severity codes unless you are trained to do so.

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.
🔄

How to Clear Code C1704

What happens after you fix the fault

Once the fault is repaired, C1704 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.