Faulty IMRC actuator or solenoid (internal short); Damaged or chafed wiring in the IMRC circuit (short to ground); Corroded or loose electrical connector at the IMRC actuator; Failed PCM driver circuit (less common); Intake manifold runner flaps mechanically stuck or binding, overloading the circuit; Aftermarket or incorrect IMRC component installed

DTC codes / Mazda codes / P1569

P1569 · MazdaIMRC Circuit Low

Q: What does code P1569 mean?

IMRC Circuit Low. P1569 on Mazda vehicles indicates that the powertrain control module (PCM) has detected a low-voltage condition on the intake manifold runner control (IMRC) circuit. The IMRC system uses a solenoid or actuator to adjust intake runner flaps for optimal airflow at different engine speeds, and a low circuit signal typically means the PCM sees voltage below the expected threshold, suggesting a short to ground, a faulty actuator, or a wiring issue.

P1569 on Mazda vehicles indicates that the powertrain control module (PCM) has detected a low-voltage condition on the intake manifold runner control (IMRC) circuit. The IMRC system uses a solenoid or actuator to adjust intake runner flaps for optimal airflow at different engine speeds, and a low circuit signal typically means the PCM sees voltage below the expected threshold, suggesting a short to ground, a faulty actuator, or a wiring issue.

SystemPowertrain

Code typeMazda 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 acceleration, especially at lower engine speeds
Reduced engine power or sluggish throttle response
Rough idle or unstable idle quality
Poor fuel economy in some cases
In rare instances, a noticeable lack of top-end power

Common causes, most likely first

Faulty IMRC actuator or solenoid (internal short)
Damaged or chafed wiring in the IMRC circuit (short to ground)
Corroded or loose electrical connector at the IMRC actuator
Failed PCM driver circuit (less common)
Intake manifold runner flaps mechanically stuck or binding, overloading the circuit
Aftermarket or incorrect IMRC component installed

How to diagnose and fix it

Perform a visual inspection of the IMRC actuator and its wiring harness for obvious damage, corrosion, or loose connections
Use a scan tool to command the IMRC actuator on and off and observe if the actuator responds and if the code returns
Measure resistance across the IMRC actuator terminals and compare to factory specifications to check for an open or shorted coil
Backprobe the IMRC circuit at the PCM connector to check for a short to ground with the actuator disconnected
Check for mechanical binding of the intake manifold runner flaps by manually operating the linkage (if accessible)
If wiring and actuator test good, substitute a known-good IMRC actuator to see if the code clears
If all components test good, diagnose the PCM driver circuit or replace the PCM as a last resort

IMRC Circuit Low: Beyond the Actuator

A low circuit code often results from a short to ground in the wiring harness where it rubs against the engine block or intake manifold, not from a failed actuator.
Mechanical binding of the intake runner flaps can cause the actuator to draw excessive current, setting a low circuit code even though the actuator itself is fine.
Some technicians replace the IMRC actuator only to find the connector pins are pushed back or corroded, creating a high resistance that mimics a low circuit.
The IMRC system may be disabled by the PCM after setting this code, leading to reduced performance that the driver may not immediately associate with the fault.
On certain Mazda engines, the IMRC actuator is integrated into the intake manifold and cannot be serviced separately, requiring manifold replacement if the actuator fails.

Can I keep driving with P1569?

You can generally continue driving with P1569, but expect reduced engine performance and possibly lower fuel economy. Avoid aggressive acceleration or heavy loads until the fault is repaired, as the IMRC system may be disabled and the engine may not operate at peak efficiency.

Tools that help

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