V50 Electrics : Volvo v50 1,6D (06) DPF issues

[KanonTerje]

Hi there.

I was trying to figure out what's wrong with my volvo v50 1,6D (06mod), and I stumbled upon this forum and some related issues.

It all started with a clogged DPF.

Had it changed, and the pressure sensor, and the rubber pipes.
And the additiv tank refilled.
The engine also have had service (Oil, diesel filter), and the glow plugs have been measured, and are Ok.

But still it goes into limp mode for some reason, with no warning and lights in dash.

I check it with diagnostic tool and it tells me code 2A20, particulate trap faulty signal.

When the car runs idle the pressure sensor shows 0hPa (it's new), and I've even tried another, and same. But when I pull the plug it suddently jumps to 120 hPa...why?

Done some voltage Reading, but not sure if it's right...?

Strange thing is that the DPF exhaust temp sensor is also acting weird, it's like stuck on 99,96 C .. this is the old one. Could this be faulty and causing all these problems? ..And when I pull the plug it still shows 99,96 C ( and even when the engine is cold).

Any ideas?

I have some pictures maybe someone could take a look. Can send em e-mail.

Could it be a short circuit?

Best regards, Terje

[Teddy1975]

The DPF pressure sensor should only show 0hpa when the engine is off. It will jump from around 1-5 hpa while idling and up to 250-280 or so under full throttle. If it always shows 0 hpa, the ECU won't know when to initiate a DPF regeneration and your DPF will pack up.

Check the connector to the sensor and make sure none of the terminals inside are corroded and that there aren't any loose/broken wires. What brand of pressure sensor did you buy?

From the pressure sensor to the top of the DPF runs two hoses. Do you know if these were replaced with the DPF? They are made from silicone but will degrade over time from the high temperatures of the DPF, so check if they are still good and connected to the DPF. There is a small difference in the inner diameter of the hoses, also the pipes on the DPF should differ in thickness like the ones on the sensor. It is important they are connected correctly.

The wire to the temp sensor on the DPF is rather fragile and can break if the sensor isn't removed and reinstalled with care. When working correctly, it should show temps from 0, up to 650+ C, (from just started engine up to regeneration in progress), and average around 250-350C under normal driving conditions. So, it does sound like the wire is broken and a replacement temp sensor is needed.

[KanonTerje]

The DPF pressure sensor should only show 0hpa when the engine is off. It will jump from around 1-5 hpa while idling and up to 250-280 or so under full throttle. If it always shows 0 hpa, the ECU won't know when to initiate a DPF regeneration and your DPF will pack up.
-Ok thanks

Check the connector to the sensor and make sure none of the terminals inside are corroded and that there aren't any loose/broken wires. What brand of pressure sensor did you buy?
-Brand name of pressure sensor is KW, but I've tried with a different brand aswell, and both reacts same way.
-I've done some measuring with only the ignition on, but I'm not sure if the voltage Reading is right. I suspect there's something wrong (see picture)

From the pressure sensor to the top of the DPF runs two hoses. Do you know if these were replaced with the DPF? They are made from silicone but will degrade over time from the high temperatures of the DPF, so check if they are still good and connected to the DPF. There is a small difference in the inner diameter of the hoses, also the pipes on the DPF should differ in thickness like the ones on the sensor. It is important they are connected correctly.
-The hoses are new aswell, but not sure if they are connected correctly. Know they are abit different in size and dimension. This task was done by workshop. Do you know which hose goes where? I'm not surprised if the workshop managed to switch theese up.

The wire to the temp sensor on the DPF is rather fragile and can break if the sensor isn't removed and reinstalled with care. When working correctly, it should show temps from 0, up to 650+ C, (from just started engine up to regeneration in progress), and average around 250-350C under normal driving conditions. So, it does sound like the wire is broken and a replacement temp sensor is needed.
-On the connector I'm getting a Reading of 5V with ignition on, and this should be about right I think.