I really need some help on this issue with secondary intermittent code p0444 which is purge valve with open circuit. At first I had p0455 evap gross leak so I smoked my evap lines and replaced the fuel cap and purge valve which got rid of that code all together. Now I'm dealing with the purge valve open circuit code and I need help figuring out my problem. For years my purge valve always made a ticking noise and I just found out that it shouldn't. It is a intermittent problem that comes and goes so even when I test it it's hard to pinpoint the problem.

I did a continuity test on purge valve plug, wires 1 and 2 are good, volts are 13.4v which reflects my battery but I think I read it should be around 5volts. Resistance is 5 ohms which I read it should be 26 ohms and the current is 1 amp. I also read that low resistance = high current which could blow/burn my ECM (engine control module).

If anyone knows how to further test these items ECM, pressure sensor valve, ect or give any advise on common problems, its much needed. Thanks in advance.

So I'm still not sure if it's a harness issue or I also read that it could be the pressure sensor that's stuck open and not sensing the pressure in the evap lines and causing that system to fail. Correct me if my multi-meter specs are not exact.

 

To put a finer point on it, the code is triggered when that voltage is above 1/3 battery voltage, and below 2/3 battery voltage. Pages 36 - 50 of the Bosch ECU manual cover it, and how the various testing is done by the ECU. Free download in links below, under engine manuals.

 

I'm not sure how to pinpoint which manual is the Bosch ECU manual pages 36-50. I've been searching all night. Is this manual on the cobby website or the Rave site? Which manual specifically?

 

Cubby - try https://www.cubby.com/pl/LR3+worksho...uter%20Manuals You want the Bosch one.

 

Ok cool I found it, thanks for that link. I'm still trying to breakdown what it means by the threshold is 1/3 battery positive < voltage < 2/3 battery positive. Can you break that down for me? In the on position my bat I pushing 12.4 volts, running 13.4 volts.

 

Well I see you already broke it down in the earlier post. I got that part, but with this problem being intermittent I can only guess my issue is a voltage problem with my harness. So I guess my volts are varying and ranging to much which triggers a code. The continuity test is useless because the connection of the wire can change for unknown reasons. So my harness is already broken down on the ground side to my ECM so now I have to check the batt side for open wire.

 

Does anyone else have some input on this issue Code P0444 for an open circuit problem in a wiring harness? Any ideas or experiences will help me out a great deal.

 

The measurement would not be at the battery terminals.

Look at page 54 of 152 in the circuits manual for D2 (the 2003 version I peeked at).

The pump has a brown with pink wire, which is 12 volts from fuse 2 when the main relay powers up sensors, also feeds the O2 sensors. A pink with orange wire leaves the pump for the ECU. Evap wiring is just above that on schematic. Look at the tiny numbers along the wire at junctions and connectors. Then switch to the electrical library, connectors,and look it up by number. There is a picture of the connector location and layout of the connector so you can be sure you are on the right wire. From the schematic, it looks like the wires go thru several header connectors.

 

Ok I'll check it out, see what's going on.

 

I have a 99 Disco2 and as you can see I have the above problems with my purge valve open circuit, I feel as though the problem is fixed but I think that I may have to do a Drive Cycle for my ECM to accept the changes that I have done to my system. Can anyone confirm that for me? Thanks