ttw18

Does the OBD trip a check engine light only AFTER all the readiness codes are set? I am missing only 1 readiness code (o2 sensor) and am wondering once it is set if I will get a code for the SAI. All my systems with the exception of the oxygen sensor say "ready" on my scanner.

MarkD

yes, all must be "ready" (as read by scanners)

Sounds like you had an SAI fault prior?
If so, it may take a while for it to pop up again.

ttw18

I mean, do all readiness monitors need to be set before it throws a "check engine light." Or if you have a fault, will it trip a light immediately, even if all monitors are not set. I do have a previous SAI fault code. I am afraid that once the last readiness monitor is set (02 sensor) the CEL will come on for the SAI. Is that how it works?

My smog is due next week. I have been reading up on the strategies for setting the monitors. I just don't want to waste my time if the OBD is waiting to throw the code.

Don't lift

In California I believe you are allow to have 2 readiness code NOT set and still pass !
Call up your smog place and ask them. Good luck.
_____________
'97 Blk/Blk C2S

g_murray

Hi,
Our cars (OBD ii -- 1996...) have 8 readiness monitors. The SLOWEST to 'set' are the ones for the cats. The fastest to 'set' are the EZ ones, (so to speak), e.g. the misfire monitor, etc.
Once a particular readiness monitor has 'set' - then the system that THAT monitor is ....yes, monitoring... needs to be working, within parameters, otherwise you'll first get a pending code and then a full-blown DTC (stored) code ...yes, a CEL.
Think about it, why would the misfire monitor have to wait until the cats are 'set' before telling you that you have a bad spark-plug?
IMHO, you should do the 'BMW drive cycle' (do a search) and get that last, pesky, cat-monitor to 'set' and then skootch over to your friendly Emissions/Inspection station. I would NOT turn off the car because the SAI is 'checked' during the first few minutes after a 'cold-start'. With the car already running, it has already checked the SAI when you first started the car - so why give it a second chance to possibly ruin your day? IMHO, 'wasting' a couple of bucks of gas, by letting it idle, whilst the tech-guyz get their wires in order, is better than getting a CEL. Also, by letting it idle, you're being sorta passive-aggressive in letting them know that they can't lolly-gag and need to attend to you lickety-split.
If some (lazy/on-my-cellphone) tech mumbles "Hey man, I suggest you turn your car off until we're ready" I would simply say: "MY car is ready ...why aren't you?" and leave it running so as to make the point.

Just my $0.02,

Gerry

csmab

You can have a CEL before the readiness codes are set. I don't think the logic for triggering a CEL is dependant on readiness codes being "set" or whether they are still in the "not ready state". I had a CEL for random misfires. When I used my scanner to read the misfire codes I also noticed that 2 readiness codes were not set. Based on this I would say that the CEL can be triggered anytime regardless of the readiness codes.

e9stibi

Same for Texas for cars of the age of a 993. It is important that ANY "failed" code will let you fail the inspection. The "flexibility" is provided only for "not ready" codes. Check with your DPS on your local regulation.

ttw18

My reason for asking is that on a few occasions when I erased the code, the CEL for SAI would return when I driving on the freeway. It just made me wonder why then?