Faulty intake manifold runner control (IMRC) actuator or solenoid; Damaged or disconnected wiring in the IMRC circuit (open, short, or high resistance); Corroded or loose electrical connector at the IMRC actuator or PCM; Failed IMRC position sensor (if equipped) sending an incorrect signal; Carbon buildup or mechanical binding in the intake runner linkage, preventing proper movement; PCM software glitch or internal fault (less common); Vacuum leak or diaphragm failure in vacuum-operated IMRC systems (on older Ford engines)

DTC codes / Ford codes / P1516

P1516 · FordIntake Manifold Runner Control Input Error

Q: What does code P1516 mean?

Intake Manifold Runner Control Input Error. P1516 on Ford vehicles means the powertrain control module (PCM) has detected an electrical input error from the intake manifold runner control (IMRC) system, which manages the butterfly valves in the intake runners to optimize airflow at different engine speeds. The PCM expects a specific voltage or signal from the IMRC actuator or sensor circuit, and the reading falls outside the acceptable range, indicating a fault in the wiring, actuator, or control module.

P1516 on Ford vehicles means the powertrain control module (PCM) has detected an electrical input error from the intake manifold runner control (IMRC) system, which manages the butterfly valves in the intake runners to optimize airflow at different engine speeds. The PCM expects a specific voltage or signal from the IMRC actuator or sensor circuit, and the reading falls outside the acceptable range, indicating a fault in the wiring, actuator, or control module.

SystemPowertrain

Code typeFord specific

SeverityMedium

Fix difficultyIntermediate

AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Slight hesitation or stumble during light acceleration, especially when the engine is cold
Reduced engine power or poor throttle response at certain RPM ranges
Rough idle or unstable idle quality in some cases
Decreased fuel economy due to incorrect intake airflow tuning
In rare cases, a noticeable lack of top-end power as the runners fail to open

Common causes, most likely first

Faulty intake manifold runner control (IMRC) actuator or solenoid
Damaged or disconnected wiring in the IMRC circuit (open, short, or high resistance)
Corroded or loose electrical connector at the IMRC actuator or PCM
Failed IMRC position sensor (if equipped) sending an incorrect signal
Carbon buildup or mechanical binding in the intake runner linkage, preventing proper movement
PCM software glitch or internal fault (less common)
Vacuum leak or diaphragm failure in vacuum-operated IMRC systems (on older Ford engines)

How to diagnose and fix it

Scan all modules for stored codes and freeze-frame data to confirm P1516 is the primary fault and not a secondary code.
Visually inspect the IMRC actuator, linkage, and electrical connector for damage, corrosion, or disconnected wires.
Check the IMRC circuit wiring for continuity, shorts to ground, and resistance using a digital multimeter, referring to the Ford service manual for pinouts.
Test the IMRC actuator with a bidirectional scan tool to command it open and closed while observing live data for position and voltage changes.
If vacuum-operated, inspect vacuum hoses and the actuator diaphragm for leaks or tears using a vacuum pump.
Clean or repair mechanical binding in the intake runner linkage, and verify free movement of the butterfly valves.
Replace the faulty IMRC actuator, sensor, or repair wiring as needed, then clear codes and verify the repair with a road test.

What Ford Techs Check Before Replacing IMRC

A stuck or carbon-fouled IMRC linkage can mimic an electrical fault by forcing the actuator to draw excessive current, setting P1516 even when the actuator itself is good.
On many Ford engines, the IMRC is vacuum-operated, and a leaking vacuum hose or failed diaphragm often sets P1516 without any electrical issue, so always check vacuum integrity first.
P1516 can be triggered by a low battery or charging system problem that causes a voltage spike or drop, so verify battery and alternator health before condemning the IMRC.
The IMRC position sensor signal can be skewed by a poor ground connection at the engine block, leading to false P1516 codes that disappear after cleaning grounds.
After replacing the IMRC actuator, some Ford models require a PCM relearn or idle relearn procedure to prevent the code from returning immediately.

Can I keep driving with P1516?

You can usually drive with P1516, but expect reduced performance and possible hesitation; avoid heavy acceleration or towing until the fault is repaired to prevent further damage to the intake system.

Tools that help

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Guidance is general and written for Ford vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.