2012 Merc ML350 Bluetec - Nonstop issues with EGR - HELP
03-28-2024, 11:34 PM
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SL55AMG
2012 Merc ML350 Bluetec - Nonstop issues with EGR - HELP
Hi everyone,
I am seriously losing my mind over an ongoing issue with my 2012 ML350 diesel. For the past year, I've been dealing with an EGR problem and I'm at my wit's end with it. Last year, I started getting P0404 and P0405 EGR codes along with the CEL (Check Engine Light) on. Upon discovering that the vehicle was still under "emission" warranty, I promptly took it to the Benz dealership. They replaced the EGR valve under warranty and also addressed all pending recalls. However, the issue persisted. The dealership claimed they had replaced the faulty part and suggested I pay $800 for further diagnostics if I wanted more inspection.
I sought assistance from a few other mechanics, but unfortunately, none of them could resolve the issue. They all pointed to a faulty EGR, even though it had been replaced by the dealer. The dealership refused to replace it again, leaving me in a quandary. Desperate for a solution, I turned to a local tuner. They disabled the EGR through tuning the car, which alleviated the P0404 and P0405 codes. However, now the vehicle is throwing a P240F (EGR Slow Response) code, and it behaves strangely, exhibiting hesitation under load.
The tuner believes that installing a block off plate for the EGR might be necessary. They didn't physically remove or install any parts other than tuning the ECU. My question is, do I really need a block off plate? And if so, where can I find one? My online searches haven't yielded any results. Additionally, is there anything else I need to do for a complete EGR delete?
Any help would be greatly appreciated before I reach the point of driving this car off the cliff.
Thank you.
I am seriously losing my mind over an ongoing issue with my 2012 ML350 diesel. For the past year, I've been dealing with an EGR problem and I'm at my wit's end with it. Last year, I started getting P0404 and P0405 EGR codes along with the CEL (Check Engine Light) on. Upon discovering that the vehicle was still under "emission" warranty, I promptly took it to the Benz dealership. They replaced the EGR valve under warranty and also addressed all pending recalls. However, the issue persisted. The dealership claimed they had replaced the faulty part and suggested I pay $800 for further diagnostics if I wanted more inspection.
I sought assistance from a few other mechanics, but unfortunately, none of them could resolve the issue. They all pointed to a faulty EGR, even though it had been replaced by the dealer. The dealership refused to replace it again, leaving me in a quandary. Desperate for a solution, I turned to a local tuner. They disabled the EGR through tuning the car, which alleviated the P0404 and P0405 codes. However, now the vehicle is throwing a P240F (EGR Slow Response) code, and it behaves strangely, exhibiting hesitation under load.
The tuner believes that installing a block off plate for the EGR might be necessary. They didn't physically remove or install any parts other than tuning the ECU. My question is, do I really need a block off plate? And if so, where can I find one? My online searches haven't yielded any results. Additionally, is there anything else I need to do for a complete EGR delete?
Any help would be greatly appreciated before I reach the point of driving this car off the cliff.
Thank you.
Last edited by HeatGun; 03-28-2024 at 11:50 PM.
03-29-2024, 12:12 PM
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W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
Now that you've tuned the car all bets are off, but I've heard of cars throwing a P240F when the DPF is clogged, which would furthermore explain the hesitation under load. Has anyone checked the DPF? When was the last time the car performed a successful regen cycle?
03-29-2024, 01:28 PM
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1922 Ford Model T / no OBD
If dealer replaced parts and did not resolve the issue, the next step would be a call to MB hotline.
But you'd have to reverse the tuning.
I suspect there might be more to the story?
But you'd have to reverse the tuning.
I suspect there might be more to the story?
03-29-2024, 05:29 PM
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If your EGR valve is bad there's a good chance that it's feeding exhaust gas when it shouldn't. No amount of programming will change that. So, a block-off plate is a good idea. All it usually is is a stainless steel plate shaped like the gasket, that goes between the EGR valve and the manifold.
03-30-2024, 02:12 PM
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If your EGR valve is bad there's a good chance that it's feeding exhaust gas when it shouldn't. No amount of programming will change that. So, a block-off plate is a good idea. All it usually is is a stainless steel plate shaped like the gasket, that goes between the EGR valve and the manifold.
That's what I was thinking. Unplugging the EGR plug while in closed mode eliminates the hesitation during acceleration, but then it generates more CEL codes due to not connecting the sensor.
Do you have a link for a block-off plate for this vehicle? I can't find one. Thank you.
