Damaged or disconnected electrical connector at the engine mount actuator; Open or shorted wire in the engine mount control circuit (often due to chafing or heat damage); Failed engine mount actuator solenoid or vacuum valve; Blown fuse or faulty relay supplying power to the mount control circuit; Corroded or broken ground connection for the mount control circuit; Internal fault in the PCM driver for the mount control circuit (rare)

DTC codes / P0Axx · Hybrid propulsion / P0A15

P0A15Engine Mount Control Circuit Low

Q: What does code P0A15 mean?

Engine Mount Control Circuit Low. P0A15 indicates that the powertrain control module (PCM) has detected a low voltage condition on the engine mount control circuit, which typically commands a vacuum or electronic actuator to soften or stiffen the mount. The PCM sets this code when the circuit voltage falls below the expected threshold for a calibrated time, indicating a short to ground, an open circuit, or a faulty actuator.

P0A15 indicates that the powertrain control module (PCM) has detected a low voltage condition on the engine mount control circuit, which typically commands a vacuum or electronic actuator to soften or stiffen the mount. The PCM sets this code when the circuit voltage falls below the expected threshold for a calibrated time, indicating a short to ground, an open circuit, or a faulty actuator.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaHybrid propulsion

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Increased vibration or harshness felt through the steering wheel, seats, or floorboards
Clunking or thumping noises from the engine bay during acceleration or deceleration
Rough idle quality or excessive engine movement when shifting between drive and reverse
In some vehicles, a default mode that locks the mount in a stiff setting, reducing ride comfort

Common causes, most likely first

Damaged or disconnected electrical connector at the engine mount actuator
Open or shorted wire in the engine mount control circuit (often due to chafing or heat damage)
Failed engine mount actuator solenoid or vacuum valve
Blown fuse or faulty relay supplying power to the mount control circuit
Corroded or broken ground connection for the mount control circuit
Internal fault in the PCM driver for the mount control circuit (rare)

How to diagnose and fix it

Inspect the engine mount actuator connector for corrosion, loose pins, or damage and repair as needed
Check the fuse and relay associated with the engine mount control circuit and replace if faulty
Measure resistance and voltage on the control circuit wiring to identify opens or shorts, repairing the harness as required
Test the engine mount actuator with a scan tool or direct power/ground to verify operation, replacing it if it fails
Verify the ground circuit for the actuator has less than 0.1 volts drop under load, cleaning or tightening connections as necessary
If all external circuits and components test good, check for PCM software updates or internal driver failure before replacing the PCM

Engine mount code misdiagnosis traps

A low voltage code often results from a simple unplugged connector after engine service, so always check connection integrity before condemning the mount.
The engine mount control circuit may share a fuse or ground with other systems, so a blown fuse can cause multiple codes and misleading symptoms.
Some vehicles use vacuum-operated mounts; a vacuum leak or failed vacuum solenoid can set this code even when the electrical circuit is intact.
The PCM may set P0A15 intermittently due to vibration-induced wire chafing, so wiggle-test the harness while monitoring live data.
Replacing the engine mount without diagnosing the circuit can lead to repeat failures if the underlying wiring or connector issue is not corrected.

Can I keep driving with P0A15?

You can generally continue driving with P0A15, but avoid aggressive acceleration or heavy loads that increase engine movement, and address the issue promptly to prevent mount wear or damage to other components.

Tools that help

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