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2022 Audi e-tron - Regenerative Braking Feels Weak/Inconsistent

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Mike T. · rep 0 · May 25, 3:13 AM · 1 replies · solved · Question

Vehicle: 2022 Audi e-tron 55 Quattro

Hi everyone, I'm an owner of a 2022 Audi e-tron 55 Quattro, and I've noticed something strange with the regenerative braking lately. Usually, when I lift off the accelerator or lightly press the brake pedal, the regen braking feels strong and consistent, especially in 'B' mode. However, in the past few days, it feels much weaker and less predictable.

Sometimes it seems to engage normally, but other times it feels like the car is just coasting more than usual, and I have to use the friction brakes more often. There are no warning lights on the dash, and the regular friction brakes seem to work fine. I've tried cycling through the drive modes and adjusting the regen levels via the MMI, but it doesn't seem to make a difference.

Is this a known issue, or could something be going wrong with the system? I'm wondering if it's related to battery temperature, or maybe a sensor issue that hasn't triggered a fault code yet. Any insights would be appreciated before I take it to the dealer.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 3:13 AM

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ClearTheCode admin answer:

Inconsistent regenerative braking on an Audi e-tron can be concerning, especially since it's a key part of the driving experience and efficiency. While it might feel like a fault, there are several normal operational factors that can influence regenerative braking strength, as well as potential issues:

Normal Operational Factors Affecting Regen:

  1. Battery State of Charge (SoC): If your e-tron's battery is near 100% charged, the regenerative braking will be significantly reduced or disabled entirely. This is because there's no capacity to store the energy generated. The car will rely more on friction brakes in this scenario.
  2. Battery Temperature: Extremely cold or hot battery temperatures can limit regenerative braking. In very cold weather, the battery management system might reduce regen to protect the battery, as cold batteries are less efficient at accepting a charge. Similarly, if the battery is too hot, the system might limit regen.
  3. Ambient Temperature: Cold ambient temperatures can also affect tire grip and overall system performance, leading the car's computers to reduce regen for stability.
  4. Driving Mode and Settings: While you've checked these, ensure your individual settings haven't inadvertently changed. The MMI allows for different levels of recuperation.
  5. Brake System Calibration/Learning: The e-tron's sophisticated brake-by-wire system blends regenerative and friction braking. It's constantly learning and adapting. Sometimes, minor inconsistencies can be part of this adaptive process.

Potential Issues to Consider:

  1. Wheel Speed Sensors: While you have no warning lights, a very subtle or intermittent issue with a wheel speed sensor could, in theory, cause the system to be cautious with regen, as it relies on accurate wheel speed data. However, this usually triggers ABS/ESC faults.
  2. Brake System Sensor/Actuator Fault: Less likely without a warning light, but problems with the brake pedal position sensor, brake booster, or other components in the brake-by-wire system could subtly affect regen. The e-tron uses an electro-mechanical brake booster (EMB) which is complex.
  3. Software Glitch: Sometimes, a software anomaly can cause unexpected behavior. A system reset or update might resolve this.

When to see a shop: Since there are no warning lights, it's possible this is due to one of the normal operational factors (especially SoC or temperature). However, if the inconsistency persists and is not correlated with a full battery or extreme temperatures, it's best to have it inspected by an Audi dealership.

  • They can connect to the vehicle's diagnostic system (ODIS) and check for any stored fault codes, even if they haven't triggered a dashboard light yet.
  • They can also monitor live data from the battery management system and braking system to see if any parameters are out of spec.
  • They can check for any pending software updates that might address known issues.

While it's likely not an immediate safety concern if your friction brakes are working, inconsistent regen can impact efficiency and driving feel, so getting it checked is advisable.

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