ERROR Codes P0422, P0236, P0237

[01V70XC]

New to the forum. This is my first post and let me say first and foremost thankyou to everyone of you all that take the time for this.
O.K. here's my question.... I have a 01 V70 XC with 80,000 and am wondering what is the preferred code reader for these C.E.L happy cars.? My C.E.L has been on lately more than it has been off. It started by coming on for a random amount of time then going off for a random amount of time. Now it has been on now for a solid 2 weeks. So if you all have suggestions on what code reader and where to reference the error codes I would be forever grateful. Thanks in advance to all that may reply.


Went to AutoZone and here are the Error Codes that I currently have.

1.) P0422 The PCM has determined that the main catalyst efficiency for bank 1 is below the threshold for the current engine operating conditions. (Bank 1 indentifies the location of cylinder #1, while bank 2 identifies the cylinders on the opposite bank).

2.) P0236 The PCM has determined that the input voltage for boost pressure sensor "A" is out of range for the current engine operating conditions.

3.) P0237 The PCM has determined that the input voltage for boost pressure sensor "A" is too low for the current engine operating conditions.

Once again, thanks in advance for all comments!

[Art]

Welcome to the site 01V70XC

Sorry that I can't steer you towards a specific brand name but a code reader will only provide you with OBD II codes. For cross referencing manufacturer codes and for a more comprehensive range of info you will also need access to a VADIS diagnostic disk or an All Data DIY subscription. The OBD codes that you referred to in your post are converted in the PDF below.

[01V70XC]

Hi Art,

Where should I start with these messages? Should I replace 1 or both of the O2 sensors and should I start with the boost pressure switch for the turbo related codes? Also, if you could do you have any info or diagrams that show the placement of these parts and what manual do you you recommend? Thanks alot.

[Willy]

Hi,
I would start by checking the electrical connections to the sensors, bad contacts can also cause faulty voltage.
Willy

[01V70XC]

Hi Willy,

Thank you first of all, where are these sensors at? Do you know of some kind of service manual or someplace online that I can help me locate these sensors.

[BillAileo]

If you do a site search regarding manuals you will discover that basically there are no paper versions available for these cars. Online subsciptions from Volvo are available but the costs are incredibly high. Many folks purchase VADIS CDs on Ebay that contain maintenance information. (VADIS is what Volvo used to call its digital maintenace information system; the current system is VIDA). Purchasing the disks can be an awkward process since it appears they are usually bootleg copies and may be difficult to use.

Going to the resources section of this website, or the maintenance portion of Volvospeed can sometimes produce good reference materials.

Good luck.

Bill

[Aviator]

Hi, I would start by checking the electrical connections to the sensors, bad contacts can also cause faulty voltage.
Willy

Yes, excellent advice. Most electrical problems are due to poor connections, and dirty grounds. I make sure I have a clean connection, and then twist the male pins about 10 degrees to ensure excellent contact in the female side......just be gentle joining the connector halves back together and sort of wiggle the two as you get them together. As an added safeguard against corrosion, put some dielectric grease in the female terminals before reuniting the connector halves.

Dave.

[Willy]

No, I don't know where the sensors can be found, I guess the turbo charger pressure sensor
is located in the discharge line of the turbo (between the turbo and the inlet system).
As for the other sensors, I am not sure which sensors are used as paramaters for the observed errors.
Since it is about the functioning of the catalytic convertor, you could try to look just before or after.
I do know that for a 3-way convertor to function well, it needs an alternating lean and rich running
engine to get best results for its different functions and that this is monitored by sensors before and after the convertor.
The sensor before the convertor outputs a square weve indicating the switching between rich and lean,
the sensor after the convertor should always give a constant output to indicate low hydrocarbon content.
I don't think this will help a lot, perhaps it can help you in reasoning towards the solution of the problem
I will try to find some more info.
Willy

[Willy]

Hello again,
I was able to find some time and assemble more info, see attachments, I hope it may help.
In case the info raises more questions than answers, just keep coming back

[01V70XC]

Thanks Willy,

I had the dealer go ahead and replace the boost sensor and it took care of "Turbo" related problems but know the light is back on (ECM 4801) and the are saying that I need to replace the catalytic converter with an estimate of 1074.46. Any suggestions on what to do???