96 Achieva Code P0440 / Occasional Flickering Engine Light

[HanlonsRazor]

Hi AF Gurus,

My 1996 Achieva SC 2.4L (~130K miles) is getting DTC P0440. My mechanic swapped the gas cap, but we're noticing that even though the engine light is usually off, it sort of flickers on real briefly (like a quarter second) sometimes. Has anyone seen the light briefly flicker on like that in conjunction with the P0440 code? He's having trouble diagnosing it. He's a small local guy, and he's done a lot of great stuff for us in the past, but I may have to go somewhere else if we can't solve it soon.

Thanks,
Russ

[ctwright]

http://www.obd-codes.com/p0440 That should get you pointed in the right direction.

[HanlonsRazor]

I thought I'd share my results so far.

I checked the obd-codes site, and read through the tech service bulletins from alldatadiy.com, and decided to inspect all the components of the evap system. The canister itself is a little tough to get to (gotta take off some panels with screws that are a bit rusty), but I could at least check some of the hoses going in and out. I cleaned them off, checked the electrical connection to the purge solenoid, and noticed that the vacuum hose from the canister purge solenoid to the intake manifold was crumbling and spongy. I suspect it was probably leaking intermittantly. So, I took a quick trip to the parts store, got about 6" of vacuum hose, cut it to size, and replaced the crumbling piece. One of the TSBs on alldata had said that on this car, P0440 doesn't clear properly, and the updated procedure is to disconnect the battery to clear it. So, I disconnected the negative battery cable for a few minutes. Of course, that makes the OBD "not ready", so I ran through the driving cycle listed here to get it ready for the emissions inspection. I took it back to the garage this morning, and it passed.

I can't be 100% sure it's gone for good, but I'm confident that at least the section of vacuum hose did need to be replaced. If it comes back, I'll keep looking. But at least this year's emissions inspection was passed, for less than $1 worth of vacuum hose.