Encountering warning lights on your dashboard can be concerning, especially when they relate to crucial safety systems like your Electronic Traction System (ETS) and Anti-lock Braking System (ABS). Many car owners turn to OBD2 scanners for initial diagnostics, and the Actron OBD2 scanner is a popular choice for its user-friendliness and ability to read engine codes. However, you might find yourself in a situation where your Actron scanner reports “no faults detected” while your ETS and ABS lights are stubbornly illuminated. This is a common scenario, and understanding why this happens is the first step toward resolving the issue.
One user with a 1998 Mercedes E320 experienced this exact problem. After successfully using their Actron CP9135 scanner to diagnose an ignition coil failure, they faced new ETS and ABS lights appearing, particularly when making turns. Despite scanning for codes, the Actron scanner indicated no faults. This raises important questions about the limitations of standard OBD2 scanners like the Actron CP9135 when it comes to diagnosing systems beyond the engine and emissions.
A key point to understand is that basic OBD2 scanners, including many Actron models, are primarily designed to read Diagnostic Trouble Codes (DTCs) related to the engine and emissions systems. These scanners are mandated to access standardized codes under regulations like OBD-II to monitor emissions-related components. However, systems like ABS, ETS, SRS (airbags), and transmission control often operate on different communication protocols and may store fault codes that are not accessible through a generic OBD2 scanner.
Therefore, if your Actron OBD2 scanner says “no faults detected” while your ETS or ABS lights are on, it doesn’t necessarily mean there are no problems. It likely indicates that the issue lies within a system that your scanner is not equipped to fully diagnose. To read codes from systems like ABS and ETS, you often need a more advanced scan tool. These enhanced scanners can communicate with a broader range of vehicle modules and access manufacturer-specific codes beyond the standard OBD2 protocols.
Let’s address the specific questions raised by the Mercedes owner:
(1) Do I need to purchase a different type of scanner to retrieve the ETS/ABS codes?
Very likely, yes. While your Actron OBD2 scanner is excellent for engine-related diagnostics, it may not be capable of reading the fault codes triggering your ETS and ABS lights. You should consider using a scanner that specifies it can read ABS and SRS codes, or a professional-grade scan tool that offers enhanced diagnostics for various vehicle systems, including Mercedes-Benz.
(2) Should I use my scanner to reset the IM Readiness functions?
IM Readiness, or Inspection and Maintenance Readiness, refers to the status of various emissions systems monitors. Resetting these functions is usually done after repairs to clear the monitors and allow them to run their tests again. This is generally not related to your ETS/ABS light issue. Focus on diagnosing the ETS/ABS problem first. Resetting IM Readiness functions with your Actron scanner won’t help in this situation and is typically used in emissions testing contexts.
(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 can indeed trigger ETS/ABS lights in some vehicles, including Mercedes-Benz models of that era. The brake light circuit is often integrated with the ABS and ETS systems. A problem in the brake light circuit, such as arcing or a bad bulb connection, can send erroneous signals that activate these warning lights. Addressing the brake light issue is a good starting point and could potentially resolve the 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 it, it’s still worth considering. A malfunctioning stop light switch is a known cause of ETS/ABS light issues in Mercedes-Benz vehicles. Even if the new switch seemed to test correctly, there’s a possibility of a defect or incorrect installation. Double-checking the stop light switch and its connections is advisable, especially since you’ve already explored this area.
In conclusion, while your Actron OBD2 scanner is a valuable tool for many car diagnostic tasks, it has limitations when diagnosing systems like ETS and ABS. The “no faults detected” message doesn’t mean your car is problem-free; it simply suggests the issue lies outside the scope of your scanner’s capabilities. For ETS/ABS light problems, especially on a Mercedes-Benz, consider using a more advanced scanner capable of reading ABS/ETS codes, thoroughly check your brake light system including the switch and bulbs, and if necessary, seek assistance from a qualified mechanic who has access to professional diagnostic equipment.
[
