OBD-II Code
P0A16
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$400–$1,100
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
$400 (mount) to $1,100 (mount + harness + ECU driver test).
P0A16 is the circuit-high variant of P0A14/P0A15: the engine mount control actuator command line is reading above the expected operating voltage when it should be commanded low or off, or the feedback signal is pegged above the operating window.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0A16 is the circuit-high variant of P0A14/P0A15: the engine mount control actuator command line is reading above the expected operating voltage when…
P0A16 is the circuit-high variant of P0A14/P0A15
the engine mount control actuator command line is reading above the expected operating voltage when it should be commanded low or off, or the feedback signal is pegged above the operating window. Circuit-high faults on a low-side-switched actuator (the typical configuration for active mounts) mean either a short to 12V on the command wire (chafed harness against a battery cable or a starter feed), a failed open driver FET in the ECU stuck pulled-up by an internal protection circuit, or a feedback sensor that has shorted to its reference voltage rail. Diagnostic ladder: unplug the actuator at the mount, key-on-engine-off, and measure the command wire voltage at the connector with a DMM (should read near 0V on a normally-de-energized line; reading 5V or 12V points to a short to power upstream). With the actuator unplugged, clear the code and see if it returns immediately (returns instantly means the short is upstream of the actuator); if it does not return immediately, the actuator itself was shorted internally and reading back to the ECU. Ohm the actuator solenoid (5-15 ohms healthy; a dead short reads near 0 ohms and is the most common circuit-high root cause on a high-mileage Prius mount). DO NOT probe HV orange-wire circuits with a standard multimeter. Always service HV with Class 0 1000V gloves, isolation tester (Megger), and DC-rated lugged probes; the HV interlock loop drops pack contactors at service-plug removal and must never be bypassed.
Vehicle-specific patterns2010-2015 Prius Gen 3 throws P0A16 most often from a shorted internal solenoid in the active mount itself after the hydraulic seal fails and fluid co…
- 2010-2015Prius Gen 3 throws P0A16 most often from a shorted internal solenoid in the active mount itself after the hydraulic seal fails and fluid contaminates the coil; the failure usually progresses from P0A14 (performance) to P0A16 (circuit-high) over a few thousand miles, so a customer presenting with P0A16 often has older P0A14 history.
- 2012-2015Prius Plug-In shares the mount and the progression.
- 2007-2017Camry Hybrid and 2011-2017 Highlander Hybrid throw the code with the same internal mount short pattern.
- 2005-2012Ford Escape Hybrid is a less common P0A16 vehicle and when it sets the code the harness short to a starter feed is the more likely root cause than a shorted mount.
Estimated repair$400 (mount) to $1,100 (mount + harness + ECU driver test).
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