Greetings MB fans,
I recently acquired a 2009 ML320 Bluetec with 205,000 miles on it. I have some experience with older diesels: VW's 1.6L NA, VW TDIs, Mercedes 5 cylinder OM617, but this OM642 is a whole different animal...
When I got it, I knew there were problems with the DPF: error code p2463 - soot accumulation, occasional limp mode followed by error code p0299 - turbo underboost condition.
So I got the Liqui Moly DPF cleaning kit from here: Liqui Moly DPF Cleaning Tool Kit - IDParts.com , and ran it according to the instructions. The next day, attempted to take it on a road trip. It went into limp mode after a couple miles, I reset it, goes right back to limp mode. I repeated this about 5 times, then gave up and took it back home.
One day later, my girlfriend decided to drive it across town in limp mode. She got stuck going up a tiny hill, said the car got slower and slower until it finally stalled. She drifted it into a parking lot, and there it sat for a couple days until I could come look at it.
My first thought was clogged air or fuel filters, so I replaced those. The "Y" pipe from air boxes to turbo had to come off in the process, so I got a chance to inspect the intake side of turbo, verified that it spins and the fins don't look damaged. The battery was dead, probably from the girlfriend cranking it after it stalled, and I wasn't able to jump it, so I replaced that as well.
None of that seems to have made any difference though - it still does the exact same thing my girlfriend described: The engine turns over, fires up, and sounds fine for a couple seconds. Then the RPMs drop to between 400 and 500, the whole engine shakes violently and dies. The throttle seems to have no effect on RPM. Right before it dies, a small puff of exhaust smoke comes out of the back of the engine.
It does have a couple of new error codes now: p2453 - diesel particulate filter pressure sensor "A" circuit range/performance, and p0471 - Exhaust pressure sensor "A" circuit range/performance.
Does anyone have any clues? Could water from the DPF cleaning kit have gotten inside the pressure sensor causing it to fail? Would a bad sensor really prevent the engine from running at all? Could exhaust back pressure from the clogged DPF have killed the turbo? Could it be some other completely unrelated problem, like crank shaft position sensor? (but if that were the case, would I be able to see the RPM?)
Thanks in advance,
- D
I recently acquired a 2009 ML320 Bluetec with 205,000 miles on it. I have some experience with older diesels: VW's 1.6L NA, VW TDIs, Mercedes 5 cylinder OM617, but this OM642 is a whole different animal...
When I got it, I knew there were problems with the DPF: error code p2463 - soot accumulation, occasional limp mode followed by error code p0299 - turbo underboost condition.
So I got the Liqui Moly DPF cleaning kit from here: Liqui Moly DPF Cleaning Tool Kit - IDParts.com , and ran it according to the instructions. The next day, attempted to take it on a road trip. It went into limp mode after a couple miles, I reset it, goes right back to limp mode. I repeated this about 5 times, then gave up and took it back home.
One day later, my girlfriend decided to drive it across town in limp mode. She got stuck going up a tiny hill, said the car got slower and slower until it finally stalled. She drifted it into a parking lot, and there it sat for a couple days until I could come look at it.
My first thought was clogged air or fuel filters, so I replaced those. The "Y" pipe from air boxes to turbo had to come off in the process, so I got a chance to inspect the intake side of turbo, verified that it spins and the fins don't look damaged. The battery was dead, probably from the girlfriend cranking it after it stalled, and I wasn't able to jump it, so I replaced that as well.
None of that seems to have made any difference though - it still does the exact same thing my girlfriend described: The engine turns over, fires up, and sounds fine for a couple seconds. Then the RPMs drop to between 400 and 500, the whole engine shakes violently and dies. The throttle seems to have no effect on RPM. Right before it dies, a small puff of exhaust smoke comes out of the back of the engine.
It does have a couple of new error codes now: p2453 - diesel particulate filter pressure sensor "A" circuit range/performance, and p0471 - Exhaust pressure sensor "A" circuit range/performance.
Does anyone have any clues? Could water from the DPF cleaning kit have gotten inside the pressure sensor causing it to fail? Would a bad sensor really prevent the engine from running at all? Could exhaust back pressure from the clogged DPF have killed the turbo? Could it be some other completely unrelated problem, like crank shaft position sensor? (but if that were the case, would I be able to see the RPM?)
Thanks in advance,
- D