Volvo Owners Club Forum - View Single Post - D5 (2005 on) - Oil Consumption & Soot Filter Full

Nickthecook · Oct 17th, 2018, 22:58

So today I got a multimeter between the ECM supply wire and the alternator, with Ignition in Pos2 only 5v was getting through. It measured 12v when fed straight to a ground, but this was of course unloades. I didn't have time to check that today. There's Still some work to do, but I suspect a leak from the power steering pump is causing the in built Alternater Control Module to reduce the current in order to protect the battery. In my case, I know the DPF isn't blocked and the soot filter full messages are due to incorrect sensor data as a result of the low voltage supply. However, I've replaced the DPF twice and I believe these were blocked due to parameters for successful regeneration not being met. Once the new DPF Sensor went on, I immediately got a signal low DTC. If this fault remains for a couple of drive cycles, the ECM changes it to a High Signal fault to force regeneration. On these occassions I was blowing regen smoke out the back end in under a minute. This was the firat time I had ever seen any smoke during a regeneration. I don't doubt the fuel was being post injected, but the EGR and Throttle were in the wrong positions due to the incorrect voltage it's also possible the temp sensors were not accurate too. The Throttle is controlled by a PWM signal, my limited knowledge leads me to believe the final signal will be incorrect if the starting voltage is wrong. The majority of my Soot Filter Full messages do NOT only appear as a result of high boost, but mostly during lift off and gear changes. This is down to the HPL EGR System and the relationship between the Turbo Vanes, EGR Position Sensor and Throttle being all to **** and a sudden increase in exhaust gas speed. If the Voltage issue is due to a faulty overrun pulley and alternator regulator, lift off is when the clutch would normally engage. My throttle often closes under acceleration but there is boost working against it at this point. During lift off there isn't, and it was as I got back on the accelerator that I was seeing vast amounts of blue smoke exiting the exhaust. The vacuum generated by lift off and a closed throttle was litterally sucking oil past the pistons. Since using torque to monitor the throttle position, I have substantially reduced my oil consumption.

It is entirely possible the low ECM voltage supply is caused by something else, but VIDA is showing a message below the DTC's saying it's 'Checking the Alternator Freewheel Pulley.' I've also had a leak from the Power Steering Pump. The wire from the Alternator was green with a light coloured stripe, but I couldn't tell if it was a dirty white or a pale grey. I say this only because of the green/pale grey stripe wires I found in the loom. At least one of these is a 12v switchable supply for the EGR. I haven't had time to trace the other 5 wires spliced into it yet.

What does baffle me is the complete lack of relevant DTC's. Maybe it's because the entire ECM is affected and there simply isn't the safety net there to identify this problem. The ECM also adjusts it's values over time and it's possible this is why I only picked it up when I replaced the Pressure Sensor(s) I've tried two new sensors and both resulted in a low signal fault.

It's worth mentioning that according to VIDA, there were two different Alternators used in the Euro4. Maybe this is why only some cars are affected.

I appreciate a lot of this is speculation. However, the ECM voltage supply isn't, that's fact. It.may yet transpire that the Alternator and Governor are ok and it's a bad ground or short in the Supply,. Eitherway, substancially reduced ECM Voltage can occur amd mess with a lot of systems without any indication whatsoever that something is wrong.

It's possible the car will still use a little oil, but oil rings aren't known for being selective about when and where they choose to allow oil pass. In my car for sure, the oil consumption goes through the roof during regeneration, which of course is usually instigated by a high presssire signal, rather than counters. I'm struggling to get more than 10mins to 20mins a day to investigate matters further. However, I will not give up until I have concrete proof of what is going on under that bonnet.

Oct 17th, 2018, 22:58	#15
Nickthecook Newbie Last Online: Apr 17th, 2024 22:21 Join Date: Feb 2015 Location: Newtown	ECM supply Voltage is too low - Modules & Sensor Problems. So today I got a multimeter between the ECM supply wire and the alternator, with Ignition in Pos2 only 5v was getting through. It measured 12v when fed straight to a ground, but this was of course unloades. I didn't have time to check that today. There's Still some work to do, but I suspect a leak from the power steering pump is causing the in built Alternater Control Module to reduce the current in order to protect the battery. In my case, I know the DPF isn't blocked and the soot filter full messages are due to incorrect sensor data as a result of the low voltage supply. However, I've replaced the DPF twice and I believe these were blocked due to parameters for successful regeneration not being met. Once the new DPF Sensor went on, I immediately got a signal low DTC. If this fault remains for a couple of drive cycles, the ECM changes it to a High Signal fault to force regeneration. On these occassions I was blowing regen smoke out the back end in under a minute. This was the firat time I had ever seen any smoke during a regeneration. I don't doubt the fuel was being post injected, but the EGR and Throttle were in the wrong positions due to the incorrect voltage it's also possible the temp sensors were not accurate too. The Throttle is controlled by a PWM signal, my limited knowledge leads me to believe the final signal will be incorrect if the starting voltage is wrong. The majority of my Soot Filter Full messages do NOT only appear as a result of high boost, but mostly during lift off and gear changes. This is down to the HPL EGR System and the relationship between the Turbo Vanes, EGR Position Sensor and Throttle being all to **** and a sudden increase in exhaust gas speed. If the Voltage issue is due to a faulty overrun pulley and alternator regulator, lift off is when the clutch would normally engage. My throttle often closes under acceleration but there is boost working against it at this point. During lift off there isn't, and it was as I got back on the accelerator that I was seeing vast amounts of blue smoke exiting the exhaust. The vacuum generated by lift off and a closed throttle was litterally sucking oil past the pistons. Since using torque to monitor the throttle position, I have substantially reduced my oil consumption. It is entirely possible the low ECM voltage supply is caused by something else, but VIDA is showing a message below the DTC's saying it's 'Checking the Alternator Freewheel Pulley.' I've also had a leak from the Power Steering Pump. The wire from the Alternator was green with a light coloured stripe, but I couldn't tell if it was a dirty white or a pale grey. I say this only because of the green/pale grey stripe wires I found in the loom. At least one of these is a 12v switchable supply for the EGR. I haven't had time to trace the other 5 wires spliced into it yet. What does baffle me is the complete lack of relevant DTC's. Maybe it's because the entire ECM is affected and there simply isn't the safety net there to identify this problem. The ECM also adjusts it's values over time and it's possible this is why I only picked it up when I replaced the Pressure Sensor(s) I've tried two new sensors and both resulted in a low signal fault. It's worth mentioning that according to VIDA, there were two different Alternators used in the Euro4. Maybe this is why only some cars are affected. I appreciate a lot of this is speculation. However, the ECM voltage supply isn't, that's fact. It.may yet transpire that the Alternator and Governor are ok and it's a bad ground or short in the Supply,. Eitherway, substancially reduced ECM Voltage can occur amd mess with a lot of systems without any indication whatsoever that something is wrong. It's possible the car will still use a little oil, but oil rings aren't known for being selective about when and where they choose to allow oil pass. In my car for sure, the oil consumption goes through the roof during regeneration, which of course is usually instigated by a high presssire signal, rather than counters. I'm struggling to get more than 10mins to 20mins a day to investigate matters further. However, I will not give up until I have concrete proof of what is going on under that bonnet.