Damaged wiring or connector to the mount control solenoid or actuator, such as chafing, corrosion or a short to a power feed; Faulty electrically controlled engine mount (internal solenoid or actuator fault); Poor connection or contaminated terminals at the mount or control unit connector; Open circuit or high resistance in the control or return path, giving a high voltage reading; Fault in the output driver within the controlling module; Outdated control unit software, only where the manufacturer has published a fix for this fault on the model.

P0AB8

Engine Mount B Control Circuit High.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
A: AreaHybrid propulsion
B8: FaultThe specific fault in that area

What it means

P0AB8 is the generic code for Engine Mount B Control Circuit High. The control unit drives an electrically controlled (active) engine mount and saw a voltage on that control circuit higher than expected. Typical causes are a short to voltage, a fault in the mount's solenoid or actuator, or a fault in the driver inside the control unit. Which mount is 'B', and how it is controlled, depends on the vehicle, so check the manufacturer's information for the model.

Symptoms

Warning lamp on, or a stored fault with no other signs
More engine vibration or shudder at idle, especially in gear with the brakes on
Vibration through the steering wheel, seat or floor at certain engine speeds
Harsher or noisier engine movement when starting, stopping or pulling away
Other mount-related or hybrid/engine system codes stored alongside

Possible causes

Damaged wiring or connector to the mount control solenoid or actuator, such as chafing, corrosion or a short to a power feedlikely
Faulty electrically controlled engine mount (internal solenoid or actuator fault)likely
Poor connection or contaminated terminals at the mount or control unit connectorpossible
Open circuit or high resistance in the control or return path, giving a high voltage readingpossible
Fault in the output driver within the controlling modulerare
Outdated control unit software, only where the manufacturer has published a fix for this fault on the modelrare

How to diagnose

Read all stored codes and freeze frame data, noting when the fault set and whether it is current or intermittent
Check for manufacturer service bulletins or known issues for this model and engine
Visually inspect the wiring and connector at engine mount B for chafing, heat damage, corrosion, water ingress and a secure fit
Check the mount for oil leaks, collapsed rubber or physical damage, and check that its mounting bolts are tight
Using the wiring diagram, measure the supply, control and earth at the mount connector with the circuit active, and compare with the specification
Test the mount's solenoid or actuator resistance against the manufacturer's value
Wiggle-test the harness while watching live data or the circuit voltage to find an intermittent fault
If the wiring and mount check out, check the control unit connector pins and the driver output before suspecting the module

How to fix

Repair or replace damaged wiring, and clean or replace corroded or loose connector terminals
Replace the faulty engine mount or its actuator if the electrical values are out of specification
Restore a faulty earth or open circuit in the control path
Replace or reprogram the control module only after the wiring and mount are confirmed good, and only if the manufacturer identifies it as the fault
Clear the code after the repair and road test to confirm it does not return

Can I keep driving?

Low severity

The car can normally be driven, but expect more vibration at idle and possibly extra wear on other mounts. Book it in soon, and stop if you notice severe vibration, knocking or the engine moving excessively.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.