P027C - Fuel Pump Module B Control Circuit High
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System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P027C is stored when the Engine Control Module (ECM) detects a voltage condition that is higher than the calibrated limit within the control circuit of Fuel Pump Module 'B'. In many returnless fuel systems, the ECM sends a PWM signal to a fuel pump driver module to regulate fuel pressure. A 'high' condition typically indicates a short to voltage in the signal line or a malfunction within the driver module itself. This fault prevents the ECM from accurately controlling fuel delivery, often resulting in the system defaulting to a fixed high-pressure output or complete fuel pump shut-off to prevent hardware damage.
Possible Causes
Short to voltage (12V) in the control circuit wiring harness
Faulty Fuel Pump Delivery Module (FPDM)
Corrosion or poor pin tension in the module connector
Internal ECM failure providing incorrect output signal
Symptoms
Recommended Solution
Workflow
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
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