01 Diesel Particulate Filter (DPF) Cleaning: DIY vs. Professio… • 02 P0021 A camshaft postion - timing over-advanced or system p… • 03 Understanding Gear Ratios: How Transmissions Impact Perform… • 04 This One Oil Filter Mistake Could Be Silently Destroying Yo… • 05 Unlocking the Skies: A Comprehensive Guide to Thriving in t… • 06 Unmasking the Power of ESC (Electronic Stability Control) a… • 07 The Secret ECU Behavior That Protects Your Engine Without W… • 08 How to Bring Back Engine Power Without Expensive Repairs • 09 This Everyday Habit Might Be Slowly Killing Your Transmissi… • 10 This Is Why Your Car’s Brake Master Cylinder Is Failing •

DTC codes / P0Axx · Hybrid propulsion / P0AB7

P0AB7Engine Mount B Control Circuit Low

P0AB7 indicates that the powertrain control module has detected a low-voltage condition on the control circuit for engine mount B, which is an active or electronic engine mount used to reduce vibration. The circuit is expected to carry a certain voltage when commanded, but the module sees the signal stuck below the normal threshold, indicating a short to ground, an open circuit, or a faulty mount.

SystemPowertrain
Code typeGeneric (all makes)
SeverityLow
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 knocking noises from the engine bay during acceleration or deceleration
  • Rough idle quality or excessive engine movement when shifting gears
  • In some cases, the engine may feel less refined at certain RPM ranges due to the mount not damping properly

Common causes, most likely first

  1. Damaged or disconnected electrical connector at the engine mount
  2. Broken or chafed wire in the control circuit between the PCM and the mount
  3. Failed active engine mount solenoid or internal short in the mount
  4. Corroded or loose ground connection for the mount circuit
  5. Faulty powertrain control module (PCM) driver circuit, though rare
  6. Aftermarket or incorrect engine mount installed that does not match the vehicle's electrical specifications

How to diagnose and fix it

  1. Inspect the electrical connector at the engine mount for corrosion, loose pins, or damage and clean or repair as needed
  2. Check the wiring harness for the mount circuit for signs of chafing, breaks, or short to ground using a visual inspection and a multimeter
  3. Measure resistance of the engine mount solenoid and compare to the manufacturer's specification to determine if the mount is internally faulty
  4. Test the control circuit voltage at the mount connector with the key on and engine off to verify the PCM is commanding the mount correctly
  5. If the circuit and mount test good, check for technical service bulletins (TSBs) or software updates for the PCM that may address false setting of this code
  6. Replace the engine mount if it fails electrical or mechanical testing, and clear the code to verify the repair
  7. If all else fails, diagnose the PCM driver circuit for the mount control, which may require dealer-level scan tools and expertise

Don't replace the mount before checking this

  • A low voltage code on an active engine mount circuit is frequently caused by a poor connection at the mount connector rather than a failed mount itself, so always inspect and clean the terminals first.
  • Some vehicles use the engine mount control circuit to also monitor mount position or vacuum, and a mechanical failure inside the mount can set an electrical code without any wiring fault.
  • The PCM may set P0AB7 intermittently if the circuit is exposed to heat or vibration, so a wiggle test of the harness while monitoring live data can reveal an intermittent short.
  • Replacing an active engine mount with a standard non-electronic mount will often cause this code to return and may affect drivability, so always use the correct OEM-type mount.
  • A weak battery or charging system issue can cause low voltage on multiple control circuits, including the engine mount, so verify battery and charging system health before condemning the mount.

Can I keep driving with P0AB7?

The vehicle is generally safe to drive with this code because the engine mount is a comfort item and does not affect safety or emissions, but prolonged driving with a failed mount can lead to increased vibration and potential damage to other components. Avoid aggressive acceleration and have the issue diagnosed soon to prevent worsening of the mount or related parts.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage