98 v70 NA P0455 - my most loyal friend

[98v70dad]

Have you checked with Volvo if your part number has been superseded? Volvo are constantly consolidating part #'s for the older cars, so perhaps your part number is now the 8627005 part #?

Neil.

I've spent several hours looking online through various sources. I don't find 8627005 crossing to 9135444 anywhere. The Pierburg part number is 722517060 and I can't find it crossing to 9135444 (Bosch) either. I guess I'll keep looking.

[cn90]

Re Bosch vs Pierburg...I posted the info in the thread below:

https://www.matthewsvolvosite.com/forums ... 6&start=14

[98v70dad]

Re Bosch vs Pierburg...I posted the info in the thread below:

https://www.matthewsvolvosite.com/forums ... 6&start=14

Thanks. The same part number you bought crosses to the part number used in my car.

[98v70dad]

Possible new development. Tonight I decided to remove the purge valve at the connection to the filter leaving the connection to the wire harness and vacuum tube to the manifold attached to see if the valve is open or closed, leaks or doesn't leak and found the following. The valve was closed for the entire time. I couldn't blow or suck air through it. I had a long long hose on the downstream side of the purge valve and I was sitting in the drivers seat. I got the same result with the car in drive and in park. It seems to me the valve should be open with the car running in order to circulate the fuel vapor and burn it. I had been driving it for about an hour.

SInce this seemed odd to me I got out my multimeter and measured the voltage at the wire harness and got a very non-committed 8V. It seems to search from 6V to 8V. The multi meter hasn't been used in a while and it needs new batteries so I'm going to replace them and repeat this tomorrow. I would guess I should be getting a steady 12V reading. Maybe I've got a fuse about to go bad ... or a bad ground or something like that. I don't do well with electronics. I constantly monitor the Voltage at the alternator and its a fairly steady 13.6V. A few months ago about the time this started I had the fuel pump relay go out and I had to remove it and jumper across with a paper clip to make it home from work (not recommended - but I had no practical choice). I don't know if that might have half burned out a fuse or may be completely unrelated.

What clues did I pick up from this, if any?

[abscate]

The purge valve is a 12 VDC open/shut valve that I think only closes at idle - it should be open at any decent revs. You may well be onto your problem.

Scour the inter webs for the wiring diagram so we can trace the 12 VDC to your purge and see if thats it

[98v70dad]

The purge valve is a 12 VDC open/shut valve that I think only closes at idle - it should be open at any decent revs. You may well be onto your problem.

Scour the inter webs for the wiring diagram so we can trace the 12 VDC to your purge and see if thats it

Well, I was at idle the entire time in the driveway and the valve stayed closed the entire time. When I check it again maybe I can take it for a ten mile drive and see what happens. I'll need a slightly longer hose. Dont know if the EVAP cycle behaves the same with a large leak (ie disconnected purge valve) or not. The thing that concerned me was the low voltage reading between the connector pins. I maybe should test it by hot wire to the connector and ground wire on the multimeter to ground somewhere in the engine bay... I really don 't know (I dont know electrical). I just put the hot and ground multimeter leads between the connector pins and took a reading which may not be correct.

My car almost overheated this August and the engine bay was so hot I had to stop and let it cool off for two hours. The wires for the purge valve live on top of the radiator more or less so maybe one of them got damaged by the heat.

My overheating problem was caused by the radiator fan not coming on because the fan had a bad ground. I have had a number of bad grounds and they all took forever to find. In fact, come to think of it, the old radiator leaked on the passenger side and I've found a good deal of corrosion on that side in the engine bay (corrosion is usually non-existent on a southern car). I wonder if the purge valve circuit grounds over on the passenger side somewhere?

I'll look for a circuit diagram. I looked in the haynes manual before posting and couldn't find it.

[abscate]

I had a peek at my 1999 diagram and the purge valve 12V comes off the ECU and grounds to chassis.

Your 1998 is probably similar but find the diagram on the web and confirm

[98v70dad]

I had a peek at my 1999 diagram and the purge valve 12V comes off the ECU and grounds to chassis.

Your 1998 is probably similar but find the diagram on the web and confirm

I've been looking for a wiring diagram and have had no luck so far. I'll look some more tonight when I get home. The generic diagram in the back of my Haynes manual shows the circuit going to the ECU which is grounded to the chassis just below the headlight and the the other side of the circuit goes directly to the fuse box. The ground is directly below the fill for the wiper fluid so it makes sense that it might be corroded. I'm planning to look at it tonight. The purge valve is on the same circuit as the fuel injectors (on the generic diagram) which is interesting since I shorted the fuel relay to get home a few months ago. I'm going to pull that fuse and look at it when I get home since the intentional short may have put too much current though the fuse.

[sleddriver]

I struggled long and hard with this arch nemisis....the dreaded P0455. Spent years. Thought I solved it at least twice, but over time = no joy. Read everything I could find, built my own smoker, used an airbrush compressor to pressurize and pull vacuum on everything. Pressure tested the fuel tank. Royal PITA...After two aftermarket gas caps, I went back to OEM. MUCH better seal. I also replaced the PURGE valve and cut the small dia. hard-line connector off the charcoal canister, replacing it with silicone tubing. Though this joint didn't leak smoke, it loudly squeeked when moved and I'd viewed it as suspect for quite some time. On my car, the CharCan is in the rear.

The sled remains free of the dreaded P0455 to this day....amazingly. We'll see if it passes the 6 month test. Most aggravating thing I've ever dealt with on ANY car I've owned in 35yrs....

You read my write-up over at BITOG:

http://www.bobistheoilguy.com/forums/ub ... /2755714/2
http://www.bobistheoilguy.com/forums/ub ... ost3868245
http://www.bobistheoilguy.com/forums/ub ... ost3889512

[98v70dad]

Today I put fresh batteries in the multi-meter and still get the 7.5 to 8 volt reading between the plus and minus wires. I get 13 volts between the plus wire and a good ground so I suspect that my ground wire is damaged. About 1.5 inches from the purge valve connection the ground wire seems to have a weak spot. Next weekend I'lltroubleshoot that section, cut out that section if its bad and splice in a good piece of wire. Hopefully that will fix it.