P0121 and a bang

[v70rade]

Two things which pop into mind quickly reading this thread:

1. Does the ETM / electronic throttle need to be re-set / reprogrammed by Volvo if 'main' parts have been replaced? - I don't know the details of replacements, however I have recently had an ETM TPS #2 failure, which prevented the car from running properly at idle, and if driven it was very lumpy and gutless? - I managed to reset the codes using Vida (with the car running) and drove the car (with reasonable performance, but ETM and ECU lights on) for nearly two weeks whilst waiting for my contactless TPS to arrive? - When I fitted the new TPS to the original ETM, all faults cleared and the running is top notch, but it was my understanding that if you replaced either the ETM or the Throttle pedal then it required a trip to the dealer?

2. Have you checked the recirculating 'dump-valve' Diaphragm on the turbo to make sure it hasn't ruptured? - this can be checked doing a low pressure (4 or 5 psi) check down the vacuum line to the valve - if it doesn't hold you'll need to romove the valve and check the diaphragm. Mine went with a 'pop' about 5 years ago and at the time the replacement from Volvo was about £125 just for a bit of rubber!

Good luck.

Ade

[deathrider311271]

Thanks Ade

As far as im aware its 2002 onwards they require a trip to the dealer. i will try your method for the recirculating dump valve

[960kg]

I know you don`t like Volvo spark plugs but have you fitted them yet, also how much were your new O2 sensors?

[deathrider311271]

I know you don`t like Volvo spark plugs but have you fitted them yet, also how much were your new O2 sensors?

yes it has Volvo spark plugs and the O2 sensors are genuine bosch units, bought from a bosch dealer exactly the same numbers as the original volvo items but a third of the price

[960kg]

bought from a bosch dealer exactly the same numbers as the original volvo items but a third of the price

That might be your problem !! but everyone to there own.

Bosch make Spark Plugs but they won`t work 100% in a Volvo only the Bosch /Volvo spec. ones do which are copyright and only available from Volvo ...... So Ok, you have the Bosch O2 sensor but you may find that they are not the same spec as the Bosch ones made for Volvo under copyright!

It may be to your advantage to get the voltages read given out by the sensors when running, then this will tell you if your ok or not.