Trying to resolve an engine light

[daveyh86]

Afternoon, I have owned my 52 plate V70 2.4 N/A for 5 weeks now. In that time I have been desperately chasing down a recurring engine warning light. Initially it was throwing a P0172 (rich condition) code. Checked for vacuum leaks and replaced some suspect hoses.

After clearing the code I have since replaced...

MAF sensor (HAAS brand)
ECT sensor and thermostat (which corrected the under reading temp gauge)
Pre Cat Lambda sensor (Denso 710661455 EUROCARPARTS number)
New Air filter
New Bosch spark plugs (FGR7DQE+)
Finally the purge valve (to address the starting issue after fuelling up)

Does anyone have any more suggestions? The car is now also showing a p0133 code alongside the recurring P0172 code...

I’m at the point where I’m questioning my purchase 🤔

[VOLVOBOY]

Hi.
This is a common issue. I could suggest several things but it will be easier if you google dtc p0133 Volvo. There is a wealth of stuff to read.

[100K+]

Sorry can't be of much help, and am questioning one of your decisions. I'd say the majority of people on here would say that if you HAVE to replace the MAF unit, you get a Bosch one. Volvo can be temperamental about certain components and the MAF is certainly one of them.
That's what I did several years ago when mine failed and I researched the options.

Cheers
Bob

[stuart bowes]

it's weird how cars can be picky. my previous was an impreza and that behaved itself perfectly for about 4 years, then suddenly came up with those same symptoms

spent nearly £200 on various different O2 sensors before sucking it up and buying one from the stealership for £250, lesson learnt. ECL went way straight away

not much help I know, sorry

[HankScorpio]

Stuart - your signature makes me laugh Volvo fwend

[Laird Scooby]

Originally Posted by daveyh86

Afternoon, I have owned my 52 plate V70 2.4 N/A for 5 weeks now. In that time I have been desperately chasing down a recurring engine warning light. Initially it was throwing a P0172 (rich condition) code. Checked for vacuum leaks and replaced some suspect hoses.

After clearing the code I have since replaced...

MAF sensor (HAAS brand)
ECT sensor and thermostat (which corrected the under reading temp gauge)
Pre Cat Lambda sensor (Denso 710661455 EUROCARPARTS number)
New Air filter
New Bosch spark plugs (FGR7DQE+)
Finally the purge valve (to address the starting issue after fuelling up)

Does anyone have any more suggestions? The car is now also showing a p0133 code alongside the recurring P0172 code...

I’m at the point where I’m questioning my purchase 🤔

First question is have you cleared the DTCs from the memory? You may have inwittingly already cleared the fault.

Next, how often do you use the car at the moment and is it mainly short journeys?

Third, on older Volvos, there are two separate CTSs, one feeds the temperature ghauge and the other is for the engine management only. Usually they are different sensors and won't work correctly when interposed. Are you sure you renewed the correct sensor???

Fourth, are you sure it's actually reaching the correct operating temperature? If my suspicions are correct about the CTSs, chances are the original sensor was reporting correctly and the engine is NOT hot enough so isn't responding as it should to various engine management inputs and the ECU is trying to compensate by varying the mixture, resulting in over-rich conditions.

***EDIT*** If it's of any use, there is an incomplete wiring diagram here :

http://www.myvolvolibrary.info/Tech_...Y02_Wiring.pdf

It doesn't contain the component list so your only clues as to the functions of the components shown are the wire colour codes and the position of the sensor you replaced.

[stuart bowes]

Originally Posted by HankScorpio

Volvo fwend

.. HES NOT MY F"$%$NG FRIEND! ...

such a good episode..

that and
'carly says...
"MEEEMINIMIIIMMMIIMNIINIIP"

[stuart bowes]

Originally Posted by Laird Scooby

...wiring diagram here..

legend. very useful