P0A15 — Engine Mount "A" Control Circuit Low

powertrain (engine/transmission)

Is it safe to drive?

Short-term driving is OK In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P0A15 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the engine mount "A" control for damage, corrosion, chafing or poor contact.
Subsystem check Check for supply voltage at the engine mount "A" control connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
Subsystem check Measure reference voltage, ground and signal continuity at the component connector.
Subsystem check Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P0A15 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P0A15 (parts and labor, USD, independent shop rates): Replace the faulty sensor or actuator: $150–$500; Repair wiring or connectors: $80–$250; Control module repair: $300–$1,000. Overall, fixing P0A15 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

How much does it cost to fix P0A15?

Replace the faulty sensor or actuator — $150–$500; Repair wiring or connectors — $80–$250; Control module repair — $300–$1,000. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

What does OBD2 code P0A15 mean?

Engine Mount "A" Control Circuit Low (P0A15): a powertrain (engine/transmission) fault affecting the sensor and actuator circuits. The car is usually drivable while you plan the repair. Most often caused by open or shorted wiring in the circuit, blown fuse feeding the circuit, corroded, loose or damaged connector.

Will P0A15 clear itself?

Sometimes P0A15 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What is the most common cause of P0A15?

The most common causes are: open or shorted wiring in the circuit, blown fuse feeding the circuit, corroded, loose or damaged connector.

What are the symptoms of P0A15?

Drivers most often notice: possible limp mode depending on the affected component, Check Engine Light on, the affected system operates intermittently or not at all, increased fuel consumption in some cases.

When your scanner pulls code P0A15, the powertrain control module is telling you it detected a problem with the engine mount "A" control circuit — specifically, the voltage in that circuit has dropped below the minimum threshold the factory expects. Think of it as the module seeing a signal that should be "alive" sitting too close to ground instead. This falls squarely in the powertrain fault family under the OBD2 standard, which means the issue involves the engine or transmission group of systems.

The engine mount control circuit on many modern vehicles uses electrically actuated mounts to dial in vibration damping on the fly. Instead of a passive rubber mount, these units contain a solenoid or piezo actuator that receives a control signal from the PCM or a dedicated controller. When everything works, the module commands a specific voltage and monitors the circuit for proper response. If the voltage never climbs above a defined low value — roughly a ground-level reading — the module logs P0A15. One glitch won't do it; the fault must appear consistently under specific driving conditions (engine load, RPM, vehicle speed) before the check engine light activates. That freeze frame data is your roadmap to reproducing the failure.

Setting P0A15 usually comes down to one of three root causes: a supply problem (no voltage reaching the mount), a short to ground pulling the signal down, or a failed component dragging the circuit low. The ECU doesn't guess which — it simply flags the low condition and waits for you to dig in with a multimeter and the right test sequence.

Symptoms

When P0A15 is active, you'll typically notice one or more of the following:

Check Engine Light illuminated on the dashboard
The engine mount control system behaves intermittently or stops working entirely
Some vehicles drop into reduced-power or limp mode depending on how the failed circuit interacts with other systems
Increased fuel consumption as the engine shakes more freely without proper mount damping
Excess vibration transmitted through the cabin, especially at idle or low speeds

Causes

The most frequent culprits behind P0A15, ranked roughly from most to least common:

A short to ground in the signal wire — often caused by chafed insulation rubbing against metal
Missing or interrupted supply voltage feeding the engine mount "A" control
A failed engine mount actuator or solenoid internally pulling the circuit low
An open circuit or poor connection in the wiring harness
A blown fuse protecting the engine mount control circuit
Corrosion, looseness, or physical damage at the connector terminations
A faulty ground connection for the control circuit
A problem with the control module driver itself (less common, but possible)

How to Diagnose P0A15

Follow this logical sequence to pin down the exact failure without replacing parts you don't need:

Connect your OBD2 scanner, confirm P0A15 is stored, and record the freeze frame data — engine load, RPM, coolant temperature, and vehicle speed at the moment of failure. You'll use these conditions to trigger the fault again during testing.
Scan for any other trouble codes. Related codes often point to the real root cause, such as a power supply issue or a module communication fault. Also check manufacturer TSBs for your specific make and model — many P0xxx codes have published factory updates or software patches.
Perform a visual inspection of the wiring harness and connectors tied to the engine mount "A" control. Look for damaged insulation, corroded pins, backed-out terminals, or wiring that has worked loose from its routing clips.
Test at the component connector: verify that supply voltage is present, then measure resistance from the signal wire to ground. A near-zero ohm reading confirms a short to ground in the harness.
Check reference voltage, ground integrity, and signal continuity at the actuator itself. Swap to known-good references if your multimeter readings look off.
Perform a wiggle test on the harness while monitoring live data — any signal dropouts or intermittent readings point to broken wires inside the insulation.
Clear the code and complete a full drive cycle matching the freeze frame conditions. If P0A15 returns, you've confirmed the fault and can proceed with targeted repairs.

Repair Options

Once you've isolated the exact cause, choose the appropriate fix:

Replace the faulty engine mount sensor or actuator — parts and labor: $150–$500
Repair or replace damaged wiring and connectors — parts and labor: $80–$250
Control module diagnosis and repair or replacement — parts and labor: $300–$1,000

How Much Does It Cost to Fix P0A15?

The total depends entirely on which component is at fault. In the majority of cases, you're looking at a wiring repair or a failed actuator — the two cheapest scenarios. At independent shop rates (parts and labor, USD):

Wiring harness repair or connector replacement: $80–$250
Engine mount actuator replacement: $150–$500
Control module repair or replacement: $300–$1,000

For most vehicles, fixing P0A15 will run between $80 and $1,000 total. Do the diagnosis first. Jumping straight to the most expensive fix wastes money — the actuator or a simple shorted wire is far more likely than a failed control module.

Can You Drive with P0A15?

For most vehicles, the car stays drivable. You may experience rougher idle, more vibration through the floor, or slightly higher fuel consumption, but the engine and transmission still function. However, if P0A15 is accompanied by stalling, failure to start, or alerts related to brakes or steering, treat it as urgent and have it diagnosed immediately.