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Mercedes CLK Diesel Fuel Filter Heater Issue

My 2004 Mercedes CLK diesel with 53528 km is showing a fuel filter heater error, reduced power, poor response, high fuel consumption, and rough idle. I suspect a cable or plug issue. Could this be the cause, or should I look at the fuel line and filter, especially for cold starts?

4 comment(s)

Sounds familiar. My old BMW had similar cold weather fuel system issues. Check the voltage at the fuel filter heater plug when the engine is cold. It should be near battery voltage. If not, trace the wiring back to find a corroded connector or broken wire.

When tracing the wiring, are there specific points prone to corrosion or failure I should check first? What tools will I need?

Check connectors near the fuel filter and fuel line, as salt and grime build up there. A multimeter is needed to check voltage, but it's best to get it to a workshop. They'll have diagnostic tools to pinpoint the issue.

I took it to a workshop, and they found a corroded plug in the fuel filter heater circuit. Replacing the connector cost 95€, and the problems are gone. Thanks.

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