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1990 Mercedes-Benz 300E Question: Check engine light



Fuegoman, Fallbrook, CA, December 30, 2009, 11:21

Any ideas?? Check engine light won't stay off. Have spent $3K to twice repair the emissions system, oxy-sensors replaced twice and new cata-converter. I drive away from the shop and 1-2 miles later the check engine light comes on solid. Need some help, at the end of my rope. Love the car, but can't afford to continue. Thank-you.

2 Answers
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  • Answer #1

    Bret Bodas from RepairPal Test Shop, December 30, 2009, 18:27

    We will need some information to be able to offer help. We need a brief history of the codes that have been appearing in the engine control module and what repair attempts have been made. And what codes are in it now? Where have you been taking the vehicle for these repairs?

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    Visitor, September 10, 2010, 01:56

    I have the same issues-I had the same parts replaced and still-my check engine light / "limp mode" are activated on my 1993 300e, 3.2L engine 104.992 (same as the E320). My error codes at the X11/4 16-pin diagnostics connector are 6 and 5 in this order. #6=Idle speed control inoperative" test electronic accelerator and #5="Exhaust gas recirculation inoperative" test LH-SFI. Also, my cruise control just failed also!
    What should be my next step in troubleshooting?
    Thanks, AB
    What should be my next step in troubleshooting?

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  • Answer #2

    Visitor, May 07, 2011, 05:43

    Replace the EGR (Exhaust Gas Recirculation) valve. Cost about $350 (new parts and labor included) on independent european mechanic shop.

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