P0950

ASM Control Circuit [Up / Down / Auto / etc]

Powertrain Engine Cooling Active Sound Management 🟡 Moderate — Fix within a week ⚠️ Drive with Care
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What This Actually Means

In plain language — no jargon

The ASM (Active Sound Management) control circuit isn't responding properly to commands from the engine computer. Think of it like a speaker system that won't turn on or adjust volume when you tell it to.

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Symptoms You May Notice

3 known symptoms for this code
No engine sound enhancement or artificial engine noise
Check engine light illuminated
ASM system not functioning during acceleration
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU sends control signals to the ASM actuator/solenoid to modulate intake or exhaust sound. It monitors voltage feedback and circuit continuity to verify the command was received and executed properly.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
ASM Control Signal Voltage 5V or 12V depending on state No voltage change or stuck at one level
ASM Circuit Resistance 4-10 ohms Open circuit (infinite) or short (<1 ohm)
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Wiring harness and connectors
Inspect and reseat the ASM control connector at the actuator and ECU for corrosion or loose pins.
2
ASM control relay
Test or replace the relay controlling ASM circuit voltage using a multimeter.
3
ASM actuator solenoid
Replace the ASM solenoid if wiring and relay test normal but no actuation occurs.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code P0950 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.

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 P0950

What happens after you fix the fault

Once the fault is repaired, P0950 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.