P2A2D

Code

Generic P — Powertrain

Alternative Fuel Tank Shutoff Valve D Control Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 23 EN: 30 RU: 25

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Page language: EN

Causes

Open or high-resistance wiring in the valve control circuit
Short to battery voltage on the control lead
Faulty Alternative Fuel Tank Shutoff Valve D (solenoid stuck or internally open)
Poor connector contact, corrosion or bent pins
Blown fuse or relay feeding the valve circuit
Faulty PCM/ECM driver transistor or internal module fault

Symptoms

Malfunction indicator lamp (MIL) or check engine light illuminated
Related system warnings (fuel/evap) or reduced alternate-fuel operation
Fuel system may not isolate or switch correctly
No audible click from the valve when commanded
Possible drivability effects if valve required for fuel selection

What to check

Read and record all related DTCs and freeze-frame data with a scan tool
Visual inspection of valve connector, pins and wiring for damage/corrosion
Back-probe control circuit and measure voltage/key ON and while commanding valve ON/OFF
Measure coil resistance of the valve (unplugged) per manufacturer spec
Check fuses and relays feeding the valve circuit
Perform an actuator/bi-directional test from a scan tool to observe operation

Signal parameters

Expected idle state: control circuit may be pulled to battery or held near 12 V when valve inactive (varies by design); driver typically sinks to near 0 V to activate
When commanded ON: PCM output should change state (to near 0 V if low-side driver) or to PWM duty dependent level—voltage should follow command
High-voltage fault: measured voltage on control wire remains near battery voltage when PCM attempts to activate or is otherwise higher than expected
Coil resistance: typical solenoid coils often measure in the tens of ohms (consult vehicle-spec); a very high/open reading indicates an open coil

Diagnostic algorithm

Retrieve all codes and freeze-frame; note ignition/operating conditions when DTC set.
Visually inspect valve, connector and wiring harness for damage, corrosion, burns, or pin damage.
With connector disconnected, measure coil resistance across valve terminals and compare to spec. Replace valve if open or out-of-spec.
Reconnect and back-probe control circuit. With key ON (engine OFF) observe resting voltage. Command valve ON/OFF with scan tool and observe voltage change.
If control line remains at battery voltage during activation, check for short to battery (inspect wiring for chafing).
If control line is open (no voltage) or floats high only when connected, check fuse(s) and relay(s) that supply valve power/logic.
Check ground integrity and continuity of the supply/ground circuits for the valve and related modules.
If wiring and valve resistance check OK, perform a substitution or use oscilloscope to verify PCM driver output. If driver does not change or waveform is abnormal, suspect PCM fault and consult manufacturer procedures.
Repair or replace faulty wiring, connector, valve or module as indicated. Clear codes and perform road drive or monitor to confirm repair.

Likely causes

Corroded or disconnected connector at valve
Damaged insulation with short to constant 12V
Faulty valve coil with abnormal resistance
PCM output stage failed (high-side stuck or not sinking)

Fault status

⚠️ Status

Control circuit voltage for Alternative Fuel Tank Shutoff Valve D is higher than expected. Possible open/high-resistance circuit, short to battery, bad valve, poor connection, or faulty PCM driver.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours