U3563

Cathode Bypass Valve Position Sensor Circuit

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$17–56 (est.)

Symptoms

Check Engine light comes on
Deterioration of vehicle dynamics
Increased fuel consumption
Unstable engine operation at idle

Causes

Open or short circuit in the sensor circuit
Valve position sensor malfunction
Connector problems or contact corrosion
Mechanical failure of the cathode bypass valve

How to Fix

Check the integrity of wiring and connectors
Test valve position sensor
Clean contacts from corrosion
Replace sensor if necessary
Check the mechanical operation of the valve

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