P2A30

Code

Generic P — Powertrain

Alternative Fuel Tank Shutoff Valve E Control Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 16 EN: 32 RU: 17

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Page language: EN

Causes

Short to ground in the valve control wiring
Open or high-resistance wiring or connector (corrosion, broken wire, poor pin contact)
Failed shutoff valve (coil short or open)
Blown fuse or faulty relay in the alternative fuel system power feed
Poor or missing ground at valve or module
Faulty PCM/valve driver output

Symptoms

Malfunction Indicator Lamp (MIL) set
Alternative fuel system disabled or switched to fallback/fail-safe mode
Engine may refuse to run on alternative fuel or may default to gasoline/petrol
Reduced drivability or rough idle if fuel shutoff is active
Possible diagnostic trouble codes related to fuel system or EVAP

What to check

Retrieve freeze frame and live data to confirm conditions when code set
Visually inspect valve, connector and wiring for damage, corrosion, or signs of heat
Check related fuses and relays for continuity and proper seating
Backprobe the valve connector and measure voltage and ground while commanding the valve ON/OFF
Measure valve coil resistance with connector disconnected (compare to specification)
Check for continuity to ground and short-to-ground between control conductor and chassis

Signal parameters

Expected supply voltage at valve (key ON): battery voltage ~11–14.5 V
When commanded ON: control circuit should present a voltage or ground switch consistent with vehicle design (battery-level available or switched to ground) — see vehicle wiring
Valve coil resistance (typical solenoid): roughly 5–50 ohms (varies by design) — consult vehicle spec
Current draw when energized: commonly 0.1–2 A depending on coil; a short to ground will show excessive current and a blown fuse
‘Low’ fault threshold: control line voltage significantly lower than supply (near 0 V) when it should be near supply or when switching is expected

Diagnostic algorithm

Safety: Park vehicle, chock wheels, disconnect ignition if doing major electrical repairs. Use PPE.
Read and record codes, freeze frame and available live data. Clear codes and see if P2A30 returns.
Visually inspect valve E and harness for damage, corrosion, heat, pin push-out or water intrusion.
Confirm fuses/relays in the alternative fuel system power feed. Replace any blown fuses and test relay operation.
With connector accessible, backprobe the valve connector. With ignition ON (engine OFF), verify supply voltage on the power pin (should be battery voltage).
Command valve ON using a scan tool while monitoring the control pin: verify expected switching behavior (either battery voltage or switched-to-ground depending on design). Note actual voltages.
Measure coil resistance at the valve (connector disconnected). Compare to specification. Infinite or very high = open; near 0 = short.
If coil resistance is normal and supply/command signals are correct, check continuity and insulation resistance of the control wire back to the PCM for shorts to ground or opens.
If the control wire is shorted to ground or has excessive continuity to chassis, locate and repair the short. Repair or replace damaged wiring or connectors.
If wiring and valve are good but PCM output does not switch correctly, suspect PCM/driver fault. Confirm with a known-good replacement module or bench test where practical and permitted.
After repairs, clear codes and perform functional test (command valve) and a road test to verify the code does not return.

Likely causes

Damaged wiring harness where it passes through body panels or near moving parts
Corroded or water-intruded valve connector
Valve coil failed shorted to ground or internally open
Blown or corroded fuse supplying the valve
PCM driver transistor fault

Fault status

⚠️ Status

Control circuit low — the valve control circuit is reporting a voltage lower than expected. Possible short to ground, open supply, failed valve, bad connector, blown fuse, or PCM driver fault.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours