vivienbauer9

Mercedes CLA Diesel Glow Plug Issue

My 2018 Mercedes CLA with a diesel engine is stumping me The preheating lamp won't switch off, the check engine light is on, and it's smoking when I accelerate I ran a diagnostic test and it's pointing to a defective glow control unit Could a dodgy cable or plug connection be causing this

4 comment(s)

Sounds like the glow control unit is the prime suspect You mentioned cable or plug connection did you check the voltage at the glow plugs themselves Is the correct voltage even reaching them These CLAs can have some tricky wiring issues

Good point about the voltage, hadn't thought of that How would I go about checking the voltage at the glow plugs Is that something I can do with a multimeter, or am I venturing into specialist tool territory

Yes, a multimeter is what you need But if you're not completely comfortable probing around electrical components, especially with a potential short circuit involved given your symptoms, it might be worth having a trusted mechanic take a look A defective glow control unit on these can cause other problems if not addressed Either way, the repair cost is estimated at 95€ so it shouldn't break the bank

Thanks, that's solid advice I think I'll book it in with a local garage, not worth the risk Turns out it was a corroded connector on the glow plug control unit, just like you suspected New connector, all sorted Appreciate the help

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