C1902

Ride Control RR Shock Actuator Circuit Open

Chassis Chassis/Safety Suspension control 🔴 Serious — Stop or limit driving 🚫 Do Not Drive
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What This Actually Means

In plain language — no jargon

The rear right shock absorber's electrical circuit is broken or disconnected, like a lamp with a severed power cord. Your vehicle can't adjust the suspension stiffness on that corner anymore.

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Symptoms You May Notice

3 known symptoms for this code
Rough or bouncy ride on rear right side
Vehicle leans excessively when turning or braking
Suspension warning light illuminated on dashboard
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors the voltage and resistance in the rear right shock actuator circuit to confirm electrical continuity and proper coil operation. It detects an open circuit when resistance exceeds safe limits or voltage drop is absent during command pulses. The system expects a complete circuit path to the actuator solenoid.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Actuator Circuit Resistance 4-15 ohms > 50 ohms or infinite (open)
Control Voltage at Actuator 11-14V when commanded 0V or erratic supply
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Electrical connectors and wiring harness
Inspect the rear right shock connector for corrosion, loose pins, or moisture and reseat or clean with dielectric grease.
2
Wiring harness to rear right shock
Check for damaged, pinched, or severed wires along the route from chassis to actuator and repair or replace as needed.
3
Rear right shock actuator assembly
Test continuity across the actuator coil; if open, replace the entire shock assembly.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code C1902 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.
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How to Clear Code C1902

What happens after you fix the fault

Once the fault is repaired, C1902 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.