qwert

Hi, new here but long time mercedes owner... anyways i have a question and hoping you all can help me out...

my girlfreind drives a 95 E280 and she has had it at the shop several times...

Her check engine light is on and it fails smog... first they told her that the MAF sensor was bad so we had it replaced, they cleared the code and a day later the light came back on. So we returned to the shop, this time they told us the EGR valve is bad, So they replaced that... And cleared the code... now a day later the CEL is back on....

im getting frustrated and its costing alot of money.. does anyone have any advice? or know how i can check the code myself???

any info is appreciated thank you...

Richard Galing

I'm sorry to hear your troubles, this is when a genric OBD II code reader comes in handy and you can pick one at your local auto parts retailer. I've been told that Autozone will read trouble codes for free, which may be a cost effective option since you've plunge $$$ on replacement parts already.

The link below are Mercedes Benz OBD II fault codes, a path that may help you locate the culprit.

MB OBD II fault codes

Good Luck!

qwert

thanks for the help..

is there a way to check the codes without the tool? i know on my nissan truck i can check them by turning a switch on the ecu...

also i forgot to mention that they reset the code by just unpluging the battery...

I searched on this board and read that you cant clear the codes just by doing that, so is there a way to clear the codes or do i need the tool for that also??

thanks!

Richard Galing

Best to use the code reader tool or MB STAR DIA. Uplugging the battery may reset a current code on your ME control unit, I highly doubt it will clear a STORED code.

Did you say you failed emissions despite the EGR valve replaced..hummmm, read this:

Emission Failures -

High CO & low lamna reading. common causes of rich running faults are the lamna sensor or the ECU (engine control unit) both of these parts are relatively simple to check, to check the sensor strip back the insulation on the signal wire from the lamna sensor, this wire is usually black. Then hold the bare wire between your finger and thumb then touch your other hand on to the battery positive the internal resistance of your body will give 1volt at your finger tips which is what the sensor would give out when the engine runs rich, if the emissions come down then you have a faulty lamna sensor or wiring but if the emissions remain the same then the ECU is a possible fault.

qwert

After the EGR was replaced they unpluged the battery, the code was off for half a day then came back on... have not tried to smog it since the egr was replaced becuase the code is on and they will automatically fail me...

what i will probably do is take it back have them check the code with me Standing there with them so i can check it... and then if its the same code just have them clear it the proper way... and hopefully that will work..

thank you for your help!!!!