Service Engine Soon

I have the "Service Engine Soon" indicator lit up in my 1996 SL2 (124,000
km). Being a good conscientious owner I took it to the dealer to remedy the
situation.

The young man labored over his computer and the service writer quizzed me
about when I'd last fuelled up. (I'd already checked the fuel tank cap for
tightness.) They had no definite diagnosis except that it was code P0440,
Evap system.

So they cleared the code and sent me on my way, saying if it re-appeared to
return. I didn't even make it out of the auto park before "Service Engine
Soon" was back, so I returned.

Well, they'd have to do a longer diagnostic a "smoke test." 99.9 percent of
the time it was a loose gas tank cap, they said.

I haven't had time to leave the car again, but I pictured a smoke test to
have something to do with exhaust gases. However, I now think they may use
smoke to test for air leaks in the evaporation system.

Anyhow, has anyone:

1. Had that error code.
2. Had a smoke test.

Thanks for any and all replies.

 

I don't have my manual at present to look up the code. I had gotten a
similar code that read out as 'EVAP Gross leak'. This was similar to the gas
cap being left off. For me, it turned out to be the Evap system vent
solenoid that was not closing properly when the engine was started. Less
than $30 for the part. Replaced two of them so far and they seem to go
always in August.

Smoke test - no, I used the purge test port connected to my air souce (@
3psi) and looked for leaks or hissing, gas smell, etc. Finally just changed
the solenoid. Be aware that exhausted vapors are considered to be explosive.
Treat them as such.

 

Thanks for that. I will mention the solenoid when I take it in since they
seem short of ideas.

 

You were right about the solenoid. This thing has turned into a marathon.

(Days are not consecutive.)

Day 1 - They didn't get it right.
Day 2 - They overbooked and didn't get to it.
Day 3 - Diagnosed a bad solenoid. Part will take 3-5 days to arrive.
Day 4 - TBA - Install solenoid.

Had I know at the start, I might have kept driving with the light on. Am I
right in thinking it's a pollution control issue, not a driveability issue?
The car seems to drive as it always did.