Experiencing warning lights on your Mercedes-Benz dashboard can be unsettling, especially when you’re trying to diagnose the issue yourself. Like many Mercedes owners, you might reach for an OBD2 scanner, such as an Actron CP9135, hoping to quickly pinpoint the problem. These scanners are known for their user-friendliness and accuracy in reading engine codes, as one user discovered while successfully diagnosing an ignition coil failure on their 1998 W210 E320. However, what happens when you encounter more complex issues, like persistent ETS and ABS lights, and your trusty Actron scanner reports “no faults detected”?
This situation is not uncommon and brings up important questions about the capabilities and limitations of different OBD2 scanners, particularly when dealing with advanced systems in vehicles like Mercedes-Benz. Let’s delve into why your Actron Obd2 Scanner might be missing certain codes and what steps you can take to get to the bottom of those perplexing warning lights.
One of the key things to understand is that while OBD2 scanners like the Actron CP9135 are excellent for reading generic powertrain (engine and transmission) Diagnostic Trouble Codes (DTCs), they may not access codes from other vehicle systems. Systems like ABS (Anti-lock Braking System), ETS (Electronic Traction System), SRS (Supplemental Restraint System/Airbags), and even climate control often operate on separate control modules that communicate using protocols beyond the basic OBD2 standards. Therefore, a standard OBD2 scanner focused on engine and emissions might simply not be equipped to “see” fault codes stored in these specialized systems.
For example, in the case of the Mercedes-Benz W210 E320 with ETS and ABS lights illuminating, the issue likely lies within the braking or stability control systems, not directly within the engine management system that the Actron CP9135 is primarily designed to read. This explains why the scanner reports “no faults detected” – it’s not that there are no problems, but rather that the scanner isn’t looking in the right place or speaking the right “language” to communicate with the relevant control modules.
So, what are your options when your Actron OBD2 scan comes up empty for ETS/ABS lights?
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Advanced Scan Tools: To retrieve codes from systems like ABS and ETS, you will likely need a more advanced scan tool. These tools often offer enhanced diagnostic capabilities, including access to manufacturer-specific codes and systems beyond basic OBD2. Some professional-grade scanners, or even scanners specifically designed for European vehicles, can communicate with a wider range of modules in your Mercedes-Benz. These scanners can often read codes from ABS, ETS, SRS, and other systems that a basic OBD2 scanner might miss.
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Professional Diagnosis: If you’re unsure about investing in a more advanced scanner, or simply prefer expert diagnosis, taking your Mercedes-Benz to a qualified mechanic or Mercedes-Benz dealership is a reliable approach. Technicians at these facilities have access to professional-grade diagnostic equipment that can comprehensively scan all vehicle systems and pinpoint the exact cause of your ETS and ABS lights. They can also interpret complex codes and perform necessary repairs accurately.
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Investigate Potential Causes: While waiting for a professional scan or considering an advanced tool, you can investigate some common culprits for ETS/ABS lights, especially if they seem to activate during turns, as mentioned in the original scenario. Possible issues could include:
- Wheel Speed Sensors: These sensors are crucial for ABS and ETS to function correctly. A faulty wheel speed sensor is a common cause of ABS/ETS light activation, particularly when turning.
- Brake Light Switch: A malfunctioning brake light switch can sometimes interfere with ABS/ETS systems. While the user in the original post replaced their brake light switch, it’s still worth considering, especially if a replacement part was of questionable quality.
- Low Battery Voltage: Mercedes-Benz vehicles are sensitive to voltage fluctuations. A low battery or charging system issue can sometimes trigger various warning lights, including ABS/ETS.
- Steering Angle Sensor: This sensor provides information about the steering wheel’s position and angle, which is used by the ETS system. A faulty sensor could cause issues, especially during turns.
Regarding the user’s specific questions from the original post:
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(1) Do I need to purchase a different type of scanner to retrieve the ETS/ABS codes? Yes, likely. Your Actron CP9135 is probably not designed to read codes from these specific systems. Look for a scanner that specifies enhanced diagnostics or Mercedes-Benz compatibility.
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(2) Should I use my scanner to reset the IM Readiness functions? Resetting IM Readiness functions is generally related to emissions testing. If you’ve addressed an engine-related issue and need to clear codes to pass an emissions test, then yes, your Actron scanner can likely handle this. However, it’s not directly related to your ETS/ABS light problem.
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(3) I currently have one brake light that is inoperable…Could this condition be causing the ETS/ABS lights to activate? While a burnt-out brake light itself is unlikely to directly trigger ETS/ABS lights, the underlying electrical issue (like arcing) could potentially cause electrical interference or voltage fluctuations that might indirectly affect other systems. It’s best to fix the brake light issue regardless, as safety is paramount.
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(4) I have recently replaced the stop light switch…Should I replace the switch again? It’s less likely that a brand new stop light switch is faulty again, but it’s not impossible. If you suspect it, further testing or replacement could be considered, but focus on other potential causes first, especially wheel speed sensors.
In conclusion, while your Actron OBD2 scanner is a valuable tool for diagnosing engine-related issues, it may not be sufficient for troubleshooting more complex systems like ETS and ABS on your Mercedes-Benz. Understanding the limitations of your scanner and considering advanced scan tools or professional diagnosis will help you effectively decode those warning lights and ensure your Mercedes-Benz remains safe and performs optimally.
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