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sebastian manrique
sebastian manrique, Auto Mechanic
Category: Mercedes
Satisfied Customers: 782
Experience:  Director Ejecutivo at Multiservicios Cruz de las Mercedes
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I have an A class, manual gearbox, 2002 MB and it’s been on

Customer Question

Hi! I have an A class, manual gearbox, 2002 MB and it’s been on limp mode since Saturday!! Happened suddenly going up a small hill (not very incline btw), and mechanic had it today, couldn’t figure it out, cleared the faults with the machine thing/computer (?? Sorry I don’t know the name) and tracked the wheel and told me that now it’s stuck at 30! Even when you press the accelerator to drive off it goes straight to 30 mph!!! What do I do?! He has no idea and nor do I! :(Thank you in advance
Kat
Submitted: 6 months ago.
Category: Mercedes
Expert:  sebastian manrique replied 6 months ago.

Hello, I am Jose Sebastian. Your mechanic automotive expert, It's a pleasure to me to attend your question. Thank you very much for trust in just answer.

Dear customer, the limp mode is indeed when your transmission is stuck in one gear and doesn’t shift. In this condition, you only get speeds up to 30 mph max.When the sensor input values from the different sensors inside the transmission, in the valve body, MAF sensor and other parameters are outside the normal operation range, the car could go into the limp mode,The car gets in this mode to protect the car when something in the transmission goes wrong. But do not panic, the chances that its a really bad problem are slim. To get the car out of the limp mode:
first you should restart your car. if the car does not get out of the mode, there are several causes that we should check:
A faulty mass air sensor (MAS)
Electronic throttle actuator problems
EGR and exhaust fuel issues
Broken, cracked or loose wiring harnesses
A damaged brake light sensor
Corroded computer module contacts
Problems with the transmission neutral safety switch.
And first of all scan with a diagnosis automotive scanner. it will show the error codes that will explain where its the root of your problem.
Please do not replace parts without finding the root cause of your transmission problem. if the scanner does not show any error code and you can not find another scanner please check the parts i mentioned before.
Dear Customer, my goal is to give you the best advice I can and I hope that I've helped today. Please remember to rate my service by selecting from the 5 stars at the top of the screen before you leave. If you need more help, please let me know.