Encountering ETS (Electronic Traction System) and ABS (Anti-lock Braking System) lights illuminating on your Mercedes-Benz dashboard can be unsettling. Many owners, like yourself, turn to OBD2 scanners such as the Actron CP9135 to diagnose the issue. While Actron scanners are valuable tools, understanding their capabilities and limitations is crucial, especially when dealing with complex systems like those in a Mercedes-Benz. Let’s delve into how Actron OBD2 scanners work and how they can assist in diagnosing ETS/ABS light issues.
It’s great that you’ve already used your Actron CP9135 scanner to successfully diagnose an ignition coil failure. This demonstrates the scanner’s effectiveness in reading standard OBD2 Diagnostic Trouble Codes (DTCs) related to the engine and emissions systems. However, when you’re facing ETS and ABS lights, and your scanner reports “No Faults Detected,” it’s important to understand why this might be happening and what steps you can take next.
One key point to consider is that the Actron CP9135, like many basic OBD2 scanners, primarily focuses on powertrain-related Diagnostic Trouble Codes (DTCs) that are mandated by OBD2 regulations. These regulations are primarily aimed at emissions-related issues. Systems like ABS, ETS, SRS (Supplemental Restraint System/Airbags), and Transmission Control often operate on proprietary protocols outside the scope of basic OBD2 scanning for many vehicles, including Mercedes-Benz models of that era.
Therefore, when your ETS and ABS lights are activated, especially during turns as you’ve noticed, the fault codes might be stored in modules that are not accessible by a standard OBD2 scanner like the Actron CP9135 for enhanced system codes. These systems often require more advanced diagnostic tools capable of communicating with specific Mercedes-Benz modules beyond the standard OBD2 protocols.
Your questions are very pertinent to troubleshooting this situation:
(1) Do I need to purchase a different type of scanner to retrieve the ETS/ABS codes?
Likely, yes. To read fault codes specifically from the ETS and ABS systems on your 1998 Mercedes-Benz E320 W210, you will probably need a scanner that is capable of reading enhanced or manufacturer-specific codes. These scanners, often referred to as professional-grade or all-system scanners, are designed to communicate with a broader range of vehicle modules beyond the basic OBD2 requirements. Some scanners marketed as “OBD2 scanners” do include enhanced diagnostic capabilities, so it’s important to check the specifications of any scanner you are considering purchasing to ensure it lists ABS and ETS (or ESP – Electronic Stability Program, the more modern term for ETS) system coverage for Mercedes-Benz vehicles.
(2) Should I use my scanner to reset the IM Readiness functions?
Resetting IM Readiness functions (Inspection and Maintenance Readiness) is generally used after repairs to clear the emission system monitors and prepare your vehicle for an emissions test. If you haven’t performed any emissions-related repairs and are focusing on the ETS/ABS issue, resetting IM Readiness functions is unlikely to be helpful for diagnosing or resolving your current problem. It’s usually best to address the underlying issue causing the ETS/ABS lights first.
(3) I currently have one brake light that is inoperable… Could this condition be causing the ETS/ABS lights to activate?
Yes, a faulty brake light circuit, especially one with arcing issues, can indeed trigger ETS/ABS lights on Mercedes-Benz vehicles. The brake light system is interconnected with the ETS/ABS systems for safety and stability control functions. A malfunctioning brake light can send incorrect signals, confusing these systems and causing warning lights to illuminate. Addressing the brake light issue is a good step and could potentially resolve your problem.
(4) I have recently replaced the stop light switch… Should I replace the switch again?
While you’ve already replaced the stop light switch and tested the new one, it’s still worth considering if it could be contributing to the issue, especially given the complexity of Mercedes-Benz systems. Although you tested it for dead spots, a new switch could still be faulty or there might be an issue with the wiring or connections to the switch. However, given you’ve already addressed this and the brake light itself has a known issue, focusing on the brake light repair first is advisable. After resolving the brake light issue, if the ETS/ABS lights persist, re-evaluating the stop light switch or considering other potential causes like wheel speed sensors, steering angle sensors, or battery voltage would be the next logical steps.
In conclusion, while your Actron CP9135 OBD2 scanner is useful for basic engine diagnostics, it may not be sufficient to read the ETS/ABS codes on your 1998 Mercedes-Benz E320. To accurately diagnose the ETS/ABS light issue, especially considering it occurs during turns, you may need to seek a professional Mercedes-Benz mechanic or invest in a more advanced diagnostic scanner capable of reading enhanced, system-specific codes. Start by resolving the identified brake light problem, as this could be a contributing factor. If the issue remains, further investigation with appropriate diagnostic tools will be necessary to pinpoint the exact cause of the ETS/ABS light activation.
