miamayer1

Mercedes ML VANOS Problem

My 2001 Mercedes ML with a gasoline engine is showing some worrying signs The check engine light is constantly illuminated, and I've observed a noticeable increase in fuel consumption lately After hooking it up to a diagnostic tool, it's pointing towards a fault with the inlet VANOS mechanics Specifically, the error suggests either a defect in one of the camshaft solenoid valves or that power isn't getting to them correctly Given the car has only done 29406 km, this seems premature Has anyone experienced a similar VANOS failure with variable timing on this model I'm trying to gauge the extent of the problem before I potentially face a repair bill of around 250€ Any insights into this inlet camshaft issue would be greatly appreciated

A 2001 Mercedes ML owner experienced a constant check engine light and increased fuel consumption, with diagnostics indicating a fault in the inlet VANOS mechanics. Possible causes included a defect in the camshaft solenoid valves or power issues to them. Suggestions included checking the wiring harness for corrosion or damage and ensuring proper oil pressure, as these could affect the VANOS system's performance. Ultimately, the problem was resolved by replacing a faulty VANOS solenoid, which restored normal function and cleared the check engine light.

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4 comment(s)

VANOS issues are never fun I had a similar problem with my ML, though I didn't catch it as early as you have The symptoms you describe – check engine light and increased fuel consumption – are classic VANOS solenoid problems Check the wiring harness first I had a partially corroded connector that was causing intermittent issues It might be worth checking the oil too Low oil pressure can sometimes affect the VANOS system's performance It's definitely worth investigating before you start replacing parts BMW VANOS systems are notoriously similar, so looking at BMW forums might give you additional insight

Thanks for the quick response When you mention checking the wiring harness, is there a specific area I should focus on Also, was your check engine light constantly on, or was it intermittent I'm curious if the intermittent nature of the light could point to a specific cause, like a loose connection It's helpful to hear about the BMW VANOS similarities, I will dig around

The wiring connector closest to the VANOS solenoid itself is the prime suspect Give it a good visual inspection for any signs of corrosion or damage In my case, the check engine light was mostly on, but it did flicker occasionally, especially when the engine was cold If yours is intermittent, it strengthens the case for a wiring or connection problem However, given the potential for damage to the engine with variable timing issues, it's probably best to get it checked by a workshop They'll have the tools to properly diagnose the electrical system and VANOS operation

Appreciate the advice I took your suggestion and had a workshop check the wiring and VANOS solenoid Turns out, it was indeed a faulty VANOS solenoid They replaced it, and the check engine light is now off, and the fuel consumption is back to normal The final bill was indeed close to 250€ Thanks again for the help

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