Anti-lock Braking System

[Flexfer]

Would a voltage of 12.27V between the battery terminals in the trunk affect the operation of the wheel sensors? I have noticed in my handbook that one should verify the battery voltage when experiencing issues with wheel sensors. Has anybody seen this recommendation?

[coolguy]

What is the voltage when the engine is operational?

[Flexfer]

I had not considered examining it; I will need to reassess, but removing the rear panel in the trunk of an S-Class is somewhat cumbersome.

[Flexfer]

I measured the voltage when the engine was operational; it varies between 14.17 and 14.2 volts, and it is 12.2 volts when the engine is off.

[pharmoun]

The battery voltage is unlikely to be the source of issues with the wheel speed sensor. I recently encountered the message "ABS Inoperative, consult owner's manual" on my SLK. A code reader indicated a malfunction with the rear nearside wheel speed sensor, which I replaced, and after deleting the code, the ABS warning on the dashboard has ceased. However, you need a diagnostic tool that, like to MB's Xentry system, provides comprehensive information on the defect and its location. It took me less than half an hour to detach the rear wheel, remove the old sensor, install the new, reattach the wheel, and use his code reader to clear the error code and verify appropriate functionality.

[Flexfer]

I was lucky to locate an individual with an Icarsoft V3 code reader; the two front sensors need replacement, which will occur once I get them. Thank you to all correspondents for their assistance.

[HOV]

It is encouraging to see that you resolved your issue; nonetheless, I would like to point out that a resting voltage of 12.2V indicates just around 60% charge.

[Black_raven]

Provided they have determined that the sensors are defective rather than the ring in the front wheel bearing that the sensor monitors.

Additionally, are two sensors malfunctioning simultaneously? Have you recently performed any tire or brake maintenance on the vehicle?

[Flexfer]

Approximately one month ago, I replaced all the brake pads and the rear brake shoes, in addition to substituting the front offside wheel with the spare from the boot, as it became slightly distorted after traversing a large pothole in Italy, which still requires repair. It may also be prudent to verify the continuity of the sensor before investing in new sensors, which I believe are Hall Effect type, while the rear utilizes a gear tooth pickup type sensor.

[Black_raven]

Depending on the vehicle, installing a fresh tire on one side beside a worn tire on the other side results in disparate wheel speeds, which the system detects as an anomaly and triggers a fault alert.

I had similar incident with a new Vauxhall Vectra during my tenure with business vehicles. I would guess that the ABS system on that vehicle (around 1996) would be quite rudimentary by contemporary standards; but, if the malfunction manifested subsequent to the wheel replacement, it may warrant consideration prior to incurring expenses for new components.