The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2023 S90 B6 - 'Reduced Engine Performance' message and occasional limp mode

0

David L. · rep 0 · May 22, 5:11 AM · 1 replies · solved · Question

Vehicle: 2023 Volvo S90 B6 Ultimate

Hi everyone,

I'm experiencing a worrying issue with my 2023 Volvo S90 B6, which only has about 15,000 miles on it. Periodically, I get a 'Reduced Engine Performance' message on the dashboard, and sometimes the car goes into a noticeable limp mode, limiting power and speed. It usually happens under acceleration or when trying to merge onto the highway.

There hasn't been a persistent Check Engine Light, but the message is definitely concerning. After I restart the car, it often clears up for a while, but then it comes back. I'm worried about driving it like this.

Has anyone with a newer B6 engine experienced this? Could it be related to the mild-hybrid system, turbocharger, or fuel delivery? Any thoughts on what might be triggering this message would be helpful before I take it in.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 5:11 AM

0

ClearTheCode admin answer:

The 'Reduced Engine Performance' message on a modern Volvo, especially a B6 mild-hybrid, indicates that the engine control unit (ECU) has detected a fault that requires limiting engine power to prevent damage. Even without a persistent CEL, the system is logging fault codes. Here are common areas to investigate:

  1. Turbocharger/Supercharger System: The B6 engine uses both a turbocharger and a supercharger. Issues with either of these, such as a faulty wastegate, diverter valve, boost pressure sensor, or even a vacuum leak in the boost system, can cause this message. The ECU will limit power if it can't achieve target boost.
  2. Fuel System: Problems with fuel pressure, fuel injectors, or the high-pressure fuel pump can lead to insufficient fuel delivery, triggering the performance reduction. A clogged fuel filter, though less common at 15k miles, is also a possibility.
  3. Ignition System: While you don't have a persistent misfire code (P030X), intermittent issues with spark plugs or ignition coils could cause performance dips that the ECU interprets as needing a power reduction.
  4. Exhaust System/Sensors: Faulty oxygen sensors or a clogged catalytic converter can affect engine performance and exhaust gas flow, leading to the ECU reducing power. Exhaust gas temperature sensors can also play a role.
  5. Mild-Hybrid (MHEV) System: The B6 engine integrates a 48V mild-hybrid system. While less common to cause direct 'Reduced Engine Performance' for engine issues, a fault within the MHEV system's communication or power delivery could indirectly affect engine operation or trigger related warnings. This would typically show specific MHEV-related codes.
  6. Software Glitch: As with many complex modern vehicles, a software anomaly in the ECU or related modules can sometimes trigger erroneous warnings. A dealership can check for and apply relevant software updates.

When to See a Shop:

  • This issue warrants immediate professional diagnosis. The 'Reduced Engine Performance' message means the car is actively protecting itself, and continued driving could exacerbate the underlying problem.
  • A Volvo dealership or a shop with Volvo-specific diagnostic tools (like VIDA) will be able to read the stored fault codes (even if the CEL isn't on) which are crucial for pinpointing the exact cause.
  • Given your vehicle's low mileage and recent model year, it is almost certainly under factory warranty, making a dealership visit the most logical and cost-effective first step.
Menu

Help & account