P2C2E

Code

Generic P — Powertrain

Turbocharger/Supercharger Bypass Valve B Supply Voltage Low

Brand: Generic

Type: P — Powertrain

Views: UK: 21 EN: 32 RU: 22

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Page language: EN

Causes

Blown fuse or poor fuse contact for bypass valve B supply
Damaged, corroded or disconnected connector on bypass valve B
Broken or shorted wiring in the supply circuit (open/high resistance)
Low battery or poor battery/charging system voltage under load
Faulty bypass valve B (solenoid) with internal short or open coil
ECM/PCM internal output or supply fault

Symptoms

Check Engine Light / MIL illuminated
Reduced engine power or limp-home mode
Unstable or incorrect boost pressure (overboost or underboost)
Whistling/hissing from bypass valve area or boost leak symptoms
Possible poor idle or stalling if valve sticks

What to check

Read freeze frame and live data with a scan tool to confirm conditions when code set
Verify battery resting voltage and charging system (expect ~12.2–12.8 V at rest, 13.5–14.8 V charging)
Inspect fuse(s) and relay(s) for the bypass valve supply circuit
Visually inspect wiring harness, grommets and connector for valve B (corrosion, pin damage, water ingress)
Back-probe connector and measure supply voltage and control signal with key on / engine running
Measure coil resistance of bypass valve B (compare to manufacturer spec)

Signal parameters

Battery/supply voltage at valve connector: ~11.5–14.5 V (key on/run, depending on system)
Control/driver voltage: usually ECU switches ground; expect ~0 V when commanded active (grounded) and near supply voltage when off (open)
Valve coil resistance (typical solenoid range): ~6–30 ohms (check specific vehicle spec)
Cranking voltage should not drop below ~9–10 V (under-load expectation)

Diagnostic algorithm

Connect a scan tool, record freeze frame and live data. Note boost behavior and when the code set.
Check battery voltage and charging system; charge or replace battery if low and retest.
Inspect fuse(s) and related power distribution for the bypass valve circuit; replace if blown and test for recurrence.
Visually inspect the bypass valve B connector and wiring for corrosion, bent pins, or damage. Repair as needed.
With ignition on (engine off), back-probe the valve connector. Verify a stable supply voltage (near battery) at the power pin. If low or missing, trace back to fuse/relay/branch connector.
Command the valve ON/OFF with the scan tool while monitoring control signal and supply. Verify ECU is switching the control circuit (voltage change or grounding).
Measure valve coil resistance with connector disconnected. Replace valve if open or out of spec.
If wiring and valve check good, perform a continuity/resistance test from the valve connector to the ECM connector to find opens/shorts. Repair wiring faults.
If wiring and component tests are good but supply/control signals are not present or are abnormal at the ECM, suspect ECM driver or internal supply fault and consider bench/ECM testing or replacement per manufacturer procedures.
Clear codes and road-test to confirm repair; monitor for recurrence and verify correct boost control.

Likely causes

Open or corroded connector or wiring to bypass valve B
Blown fuse or poor power/ground distribution to the valve
Faulty bypass valve (coil open/high resistance)
Low system battery/charging voltage
ECM driver or internal supply fault (less common)

Fault status

⚠️ Status

MIL ON — DTC P2C2E stored: Turbocharger/Supercharger Bypass Valve B Supply Voltage Low. Freeze frame and live data available. Intermittent or current fault.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours