V50 Engine 2.0D : - Limp Mode - MAF or DPF or neither?

Volvodiesel123 · Jan 26th, 2022, 17:27

My car - Volvo V50 R Design D3 2.0 Litre Diesel Estate 2012 52,000 miles

My Story - My auxiliary drive belt shredded due to a seized (solid) AC compressor, thankfully no knock on effect with the main timing belt. Fortunately I was able to pull in fairly quickly and the AA turned up. The technician proceeded to remove what was left of the auxiliary belt and then he suggested that I drive to a nearby garage (7 miles) with him following on behind. There were all kind of warning messages subsequently came up on route and very little in the way of servo assist steering etc. After approx 4 miles the car ran out of power and needed a booster charge on route from the AA. Eventually we limped into my chosen garage (Volvo Indie with good reputation). They subsequently replaced the seized compressor and belt. However they reported that the car had gone into limp mode and that they weren't able to communicate via their VIDA (?) system. I decided to drive the car home in limp mode to look for the problem myself. I have a cheapo wireless (Amazon) OBDII reader along with the "Car Scanner Pro" app. I am fairly hands on but no expert with this reader. At first I repeatedly got the message "Mass air flow (MAF) sensor A - circuit range/performance". Following various online suggestions I cleaned the MAF sensor with a MAF cleaner even though everything about the unit looked brand new - no change. I then sprayed a "professional EGR cleaner into the air intake - no change. I then removed the CEM unit, checked all the fuses and cleaned all connections - no change. I then purchased a second hand/ tested genuine Volvo MAF sensor unit and fitted it - no change. At some point during proceedings I started receiving a further message "Diesel particulate filter (DPF) pressure sensor A - circuit malfunction".

My gut feeling now is that the EGR valve is possibly dirty (?) however there is no message up for this and so far my guessing hasn't been too good! The indie garage who fitted the A/C compressor has offered to retry their VIDA system again but at £90.00 a pop (on the understanding that they can get it to communicate). I should add that the car starts well enough but a little lumpy (not too bad - a bit "tappety") and will otherwise happily idle. However when I take it out it quickly reverts to limp mode. I've tried the trick of the message stalk and the double click fog switch, however I not sure what these messages are telling me. I have no experience of how reliable these little wifi readers are (decent write ups on Amazon).

Getting a bit tired and frustrated now - any guidance would be greatly appreciated. Thanks for reading.

Simmy · Jan 26th, 2022, 18:03

cam belt jumped a tooth.?bent valve do a compression test check timeing marks

Volvodiesel123 · Jan 26th, 2022, 20:40

Thanks.

Scary diagnosis! Is this something that you have experience of?

Why would my two bob OBDII keep on listing the MAF sensor and latterly the DPF Sensor?

Jan 26th, 2022, 17:27	#1
Volvodiesel123 New Member Last Online: Feb 4th, 2022 16:11 Join Date: Feb 2020 Location: Middlesbrough	Limp Mode - MAF or DPF or neither? My car - Volvo V50 R Design D3 2.0 Litre Diesel Estate 2012 52,000 miles My Story - My auxiliary drive belt shredded due to a seized (solid) AC compressor, thankfully no knock on effect with the main timing belt. Fortunately I was able to pull in fairly quickly and the AA turned up. The technician proceeded to remove what was left of the auxiliary belt and then he suggested that I drive to a nearby garage (7 miles) with him following on behind. There were all kind of warning messages subsequently came up on route and very little in the way of servo assist steering etc. After approx 4 miles the car ran out of power and needed a booster charge on route from the AA. Eventually we limped into my chosen garage (Volvo Indie with good reputation). They subsequently replaced the seized compressor and belt. However they reported that the car had gone into limp mode and that they weren't able to communicate via their VIDA (?) system. I decided to drive the car home in limp mode to look for the problem myself. I have a cheapo wireless (Amazon) OBDII reader along with the "Car Scanner Pro" app. I am fairly hands on but no expert with this reader. At first I repeatedly got the message "Mass air flow (MAF) sensor A - circuit range/performance". Following various online suggestions I cleaned the MAF sensor with a MAF cleaner even though everything about the unit looked brand new - no change. I then sprayed a "professional EGR cleaner into the air intake - no change. I then removed the CEM unit, checked all the fuses and cleaned all connections - no change. I then purchased a second hand/ tested genuine Volvo MAF sensor unit and fitted it - no change. At some point during proceedings I started receiving a further message "Diesel particulate filter (DPF) pressure sensor A - circuit malfunction". My gut feeling now is that the EGR valve is possibly dirty (?) however there is no message up for this and so far my guessing hasn't been too good! The indie garage who fitted the A/C compressor has offered to retry their VIDA system again but at £90.00 a pop (on the understanding that they can get it to communicate). I should add that the car starts well enough but a little lumpy (not too bad - a bit "tappety") and will otherwise happily idle. However when I take it out it quickly reverts to limp mode. I've tried the trick of the message stalk and the double click fog switch, however I not sure what these messages are telling me. I have no experience of how reliable these little wifi readers are (decent write ups on Amazon). Getting a bit tired and frustrated now - any guidance would be greatly appreciated. Thanks for reading. Last edited by Volvodiesel123; Jan 26th, 2022 at 17:38.

Jan 26th, 2022, 18:03	#2
Simmy Premier Member Last Online: Today 12:26 Join Date: Mar 2017 Location: Manchester	cam belt jumped a tooth.?bent valve do a compression test check timeing marks Last edited by Simmy; Jan 26th, 2022 at 18:06.

Jan 26th, 2022, 20:40	#3
Volvodiesel123 New Member Last Online: Feb 4th, 2022 16:11 Join Date: Feb 2020 Location: Middlesbrough	Timing belt/ bent valve Thanks. Scary diagnosis! Is this something that you have experience of? Why would my two bob OBDII keep on listing the MAF sensor and latterly the DPF Sensor?

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