Open or damaged wiring in the engine mount control circuit, such as a broken wire or disconnected connector; Failed active engine mount actuator (internal open circuit or short to voltage); Corroded or loose electrical connector at the engine mount or PCM; Short to voltage on the control wire, often caused by chafed insulation against a grounded metal surface; Faulty powertrain control module (PCM) driver circuit, though this is less common; Aftermarket electrical accessories improperly tapped into the circuit

DTC codes / P0Axx · Hybrid propulsion / P0A16

P0A16Engine Mount Control Circuit High

Q: What does code P0A16 mean?

Engine Mount Control Circuit High. P0A16 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the engine mount control circuit, which typically commands a variable-damping or active engine mount. The circuit is expected to operate within a specific voltage range, and a high reading means the PCM sees an open circuit, a short to voltage, or a faulty mount actuator.

P0A16 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the engine mount control circuit, which typically commands a variable-damping or active engine mount. The circuit is expected to operate within a specific voltage range, and a high reading means the PCM sees an open circuit, a short to voltage, or a faulty mount 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, especially at idle
Clunking or knocking 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 message on the driver information center indicating a chassis or suspension fault

Common causes, most likely first

Open or damaged wiring in the engine mount control circuit, such as a broken wire or disconnected connector
Failed active engine mount actuator (internal open circuit or short to voltage)
Corroded or loose electrical connector at the engine mount or PCM
Short to voltage on the control wire, often caused by chafed insulation against a grounded metal surface
Faulty powertrain control module (PCM) driver circuit, though this is less common
Aftermarket electrical accessories improperly tapped into the circuit

How to diagnose and fix it

Perform a visual inspection of the engine mount actuator and its connector for damage, corrosion, or loose pins
Use a scan tool to command the engine mount actuator on and off while monitoring the circuit voltage to confirm the fault
Disconnect the actuator and measure resistance across its terminals; compare to the manufacturer's specification to rule out an open or shorted mount
Check for continuity and short to voltage on the control wire between the PCM and the actuator, repairing any damaged wiring
Inspect the PCM connector for corrosion or backed-out pins, and verify the PCM ground connections are clean and tight
If the circuit and actuator test good, substitute a known-good PCM to confirm a faulty driver before replacement

What a high voltage reading really means

A high voltage code on an actuator circuit almost always indicates an open circuit or a short to voltage, not a failed mount, so resistance and voltage-drop tests are more reliable than guessing.
Many active engine mounts are vacuum-operated or electronically controlled, and a failed mount can set this code without producing any noticeable vibration, leading owners to ignore a real mechanical problem.
Technicians often overlook a chafed wire harness near the engine mount that only shorts when the engine moves under load, so wiggle tests while monitoring live data are essential.
This code can be set by a poor ground connection at the engine mount or chassis, which raises the reference voltage seen by the PCM and mimics a faulty actuator.
Replacing the engine mount without first checking the circuit voltage can result in a repeat failure if the root cause is a shorted wire or corroded connector.

Can I keep driving with P0A16?

The vehicle remains safe to drive in most cases because the fault mainly affects vibration isolation, but prolonged driving with a failed mount can accelerate wear on other driveline components. Avoid aggressive acceleration and have the circuit inspected soon to prevent secondary damage.

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.