P1516

Code

VOLKSWAGEN P — Powertrain

Intake Manifold Changeover Valve Circuit Open

Brand: VOLKSWAGEN

Type: P — Powertrain

Views: UK: 45 EN: 82 RU: 65

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Page language: EN

Causes

Broken or disconnected wiring in the valve control circuit
Corroded, damaged or loose connector at the valve or ECM
Failed intake manifold changeover valve / solenoid (open coil)
Blown fuse or faulty relay supplying the circuit
PCM/ECM driver fault (rare)
Mechanical seizure of the valve preventing expected feedback (if equipped)

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Rough idle or unstable idle quality
Reduced throttle response, hesitation or lower torque at some rpm ranges
Increased emissions or failed emissions test
Possible limp/derate mode on some vehicles

What to check

Scan for stored codes and freeze‑frame data; note conditions when code set
Confirm battery voltage and ground condition (low voltage can cause false faults)
Visually inspect valve connector and wiring for corrosion, pin damage, or disconnection
Perform wiggle test on wiring while monitoring live data or watching for code reappearance
Measure valve coil resistance with meter (compare to factory spec) to confirm open coil
Backprobe connector to check for supply voltage and control signal from ECM

Signal parameters

Valve coil resistance: typically low (single- to tens of ohms) — an infinite/open reading indicates a failed coil. Refer to factory specification for exact ohms.
Supply voltage: with ignition ON, one side of the solenoid is usually supplied with battery voltage (approx. 11–14 V); the ECM typically switches the other side to ground or modulates with PWM.
Control signal: ECM may provide a switched ground or PWM control. Expect a switched or pulsed signal when the valve is commanded; no signal indicates open circuit or ECM driver fault.
Open-circuit condition: very high or infinite resistance, no voltage at valve connector when commanded

Diagnostic algorithm

Retrieve all stored codes and freeze frame data; clear codes and retest to confirm repeatability.
Visually inspect the intake manifold changeover valve connector and wiring for corrosion, pin damage, chafing, or disconnection. Repair any obvious damage.
With ignition ON (engine off), backprobe the valve connector. Verify battery feed is present on the supply pin and check the control pin while commanding the valve ON from the scan tool. Note voltages.
Measure the valve coil resistance at the connector using a multimeter. An open (OL/infinite) reading indicates a failed solenoid coil — replace the valve.
If coil resistance is normal, check continuity between the valve connector and the ECM control pin. Repair any open or high-resistance wiring found.
If there is supply but no control signal from the ECM, confirm related fuses/relays and grounds. Wiggle the harness while monitoring to find intermittent faults.
If the ECM provides a PWM control signal but the valve does not actuate and coil resistance is acceptable, check for mechanical binding of the actuator or vacuum/supply issues if the actuator is vacuum-assisted.
If wiring and valve test good but control driver appears faulty (no control output from ECM when commanded), verify with a known-good module or consult manufacturer guidance before replacing ECM.
Repair or replace damaged wiring, connector, fuse, or valve as required. Clear codes, perform relearn/procedures if specified, and road-test to confirm repair.

Likely causes

Connector corrosion or water ingress at the valve harness
Broken wire at common stress points (harness bends, near firewall)
Failed valve/solenoid coil (open winding)
Blown fuse or poor battery/ignition power to the circuit

Fault status

⚠️ Status

Open circuit detected in intake manifold changeover valve control circuit. ECM cannot energize valve; fault stored and MIL illuminated.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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P1516 — Intake Manifold Changeover Valve Circuit Open