Hey Guys,

So A long time ago when I was supercharged I removed all my emissions stuff (engine bay), now the car is stock and needs to pass emissions. So, I've started to put the emission parts back in.

So these are the codes I got and they keep on recurring.

P1490,P1491,P1492,P446

I've tested the following:

Engine Bay Purge Solenoid (by Map/Bar Solenoid) -applied 12v, solenoid clicks and blocks air as per FSM.
Vacuum Cut Bypass Valve Solenoid -applied 12v, solenoid clicks and blocks air as per FSM.
EVAP Canistor Valve (doesn't have anything to do with the codes) -applied 12v, solenoid clicks and blocks air as per FSM.

So yah, I checked all the valves that pertain to the engine codes and I can't seem to fix this!

I have voltage to these sensors.

The codes come on without starting the car. I erased the codes, went to school (roughly 100kms) came back home and all was good, then went to a friends place 3 hours later and before starting the car I checked the codes and I had the top 4 codes pending.

I have a 1998 Maxima and have been using this to diagnose:

http://www.nicoclub.com/FSM/Maxima/1998/EC.pdf

Starting from Page 567

Any help would be appreciated, are these codes piggybacking from another issue?

 

From this picture I have tested the following and made sure they are working properly.

Bottom Left:Test/Functioning Vacuum Cut Valve Bypass Valve
Middle Bottom:Test/Functioning EVAP Vent Control Valve
Bottom Right: Replaced EVAP Pressure Sensor (had spare)
Top Right:Test/Functioning EVAP Purge Control Solenoid Valve

Can the EVAP Purge Volume Control Valve cause these issues?
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Here is another picture for reference, I've tested all the electrical components in this picture.

 

I believe the ecu controls ground on the solenoids. Have you tested for continuity between the valves and ecu connector.

 

I have not, I'll be doing this next step tomorrow.

Is there a way to test the valves visually? Like, at what condition do these valves click in and start working?

 

The EVAP PVCV that sits on the manifold could be getting proper voltage but may have debris (charcoal bits) stoping it from doing its job. Also, what condition is that canister of yours in the back in?? Mine was broken before and letting charcoal spill out

 

Could this affect everything else? I haven't taken it out or checked it as the codes didn't point to it, who knows though?

The charcoal canister looks good and intact.

 

Mine also leaks charcoal still. What generally happens is the line under the car gets a blockage. Small bits can also lodge in the valves on the manifold or the sensor behind the rear wheel.

 

I found a link (forgot where) that shows you what to disconnect to clean up blockages if the canister was leaking (by using pressurized air). So i'll definitely do this and have something catch any chunkies that may have been trapped.

 

Would you mind linking me that thread as well. Chances are mine is jammed due to previous canister.

Answering your question about the PVC valve, yes it can kick up a code, but I'm not convinced it will cause all those codes you have.

The canister can start a lot of bull man. Lol

 

http://www.aa1car.com/library/evap_n...ntb00-085a.pdf

I followed those instructions but nothing came out. It might be ecu related, if I recall I a have different ecu. I don't know if this makes a difference. My car was auto so I swapped out the ecu for a manual ecu. Unsure of year though.

Question, when you turn the key on should the solenoids in the back Click on? I ask because mine don't. I do have power but they don't click (turn on). I guess I should verify continuity from the ecu but there must be a condition I can put the car in for the ecu to activate the ground no?

 

My ecu is A18-K66 E9J

I have no clue what year this came out from...Couldn't find this model number on the JWT site :/

Edit...

From what I can tell its all the same 96-98. So my issue lies elsewhere.

Apparently the p0446 EVAP Vent control Valve should click with the key in the on position. So that's an issue I have to figure out. It does work (bench tested), just no go on the car?

 

OK, I have to many issues. So lets start of with P0446.

This is the valve that connects to the canister itself. The valve is 100% functioning on my bench test. I get power from the connector but no ground. Ground is controlled by the ECU. From the manual I should be able to turn the key to ON and the valve should close but it doesn't.

Do I check continuity next between the ground to the ecu? After this what do I do?

 

You want to make sure the negative wire is not broken, so check continuity between the ecu connector and the valve connector.

 

My evap issue is P1447. Basically means check everything. Lol

 

Guess what code I got today

I took apart the evap purge control valve (sits on the manifold) and cleaned it up. It wasn't closing all the way. Anywho cleared the codes and drove the car for 80k km's, checked the codes and got P1447. So the only thing I did was mess around with the purge control valve. I'll be grabbing another one from the junk-yard and giving it another go.

I just need the codes to stay off for a bit. I can pass with two ready checks not being ready lol. So I don't care! Bah!

 

Will do!

 

Alrighty.

Grounds seem to be fine.

I got another purge control valve and so far no codes. I've only started the car and let it idle after clearing up the codes. My old purge control valve was reading 39 ohms while the newish one reads 30 ohms as per fsm.

So yah, I'm crossing my fingers that this was the issue. I've measured everything else and I can tell you all the solenoids work. Only thing I didn't do was take out the evap canister and check to see if charcoal comes out. That's the next step but honestly I think its good as my evap lines are clean.

I'll keep you guys posted.

 

Ok, passed emissions!!!

So all my codes where caused by a purge control valve (the one that sits on the manifold).

I did test all the other sensors/solenoids and they checked out. Guess the purge control valve messed everything else up even though they were fine.

Thought I'd give some closure.

Thanks all.