MWS Performance

I'm looking for someone knowledgable with OBD II or VAG Com troubleshooting.

Car jsut turned 29K and my emissions systems doesn't appear to work properly. Ran VAG COM and got that the Cats, air injection, O2, etc. all failed or incomplete. Then under readiness I get a MILs are off. Is there anyway to turn these on through VAG COM or do I have to start replacing emission components?

MB The Body

Are you under warranty ?

MWS Performance

Ok after some searching I found out that MIL is Malfunction Indicator Light but is not on yet I'm getting readings saying my emissions system has failed??? If the pieces are faulty that are coming up not ready that car would run like crap but it doesn't it runs great just can't get my inspection sticker because OBD is not ready. I know it's a computer problem but need someone knowledgable in troubleshooting it.

Silly Boy RS4

Catalysts are warrantied for 8 years 80k.

lawong

for codes?

As long as you have no fault codes, you are find. To properly run a readiness test you need to have the car on (might also need to be warmed up.)

Diagnostic tools are dangerous. Especially in the hands of someone who doesn't understand what they are doing.

FoKai

if you decide to take the car in to the dealer

1/4 scale

blast from the past eh?

MWS Performance

I went for my sticker and was rejected because OBD is not ready, so got my hands a VAG COM to run codes and see why.

Codes said Engine Coolant Temp sensor was bad and emissions system not working. Changed ECT sensor hoping that this was causing emissions system failure. I ran codes got none so ran a readiness test but still get OBD not ready.

I don't have any MIL or CEL lights lit up, car runs as it has for last four years (bought car off sister-in-law) yet I can not get a sticker because OBD is not ready even with NO CODES.

I am trying to findout either 1) is emissions system working or 2) how do I reset OBD so I can get my sticker?

So what I am looking for is someone who understands how to get the OBD system to a ready mode so I can get a sticker.

Should mention that after ECT was replaced car was driven to bring up to temp and run both scan of codes & readiness check with car running.

Bob Petruska

If so you will get failed and incomplete. This is very normal when you click on "Clear DTCs". You reset the readiness coding. You will need to just drive the car for a few days and then check the readiness screen and it will be back to normal. Remember it takes a few days to have all the readiness items come back to "passed". You can check it every day to see the "passed" list grow. This is just a normal procedure for OBDII systems and hurts nothing. If this bothers you then don't hit the Clear DTC button if you don't have any DTC Error Codes listed. There is a manual way to reset the readiness to all passed but it is so involved it's not worth it. Just drive the car for a week and everything will be rest to Passed!

Bob Petruska

READINESS FLAGS
An essential part of the OBD II system are the "readiness flags" that indicate when a particular monitor is active and has taken a look at the system it is supposed to keep watch over. The misfire detection, fuel system and continuous system monitors are active and ready all the time, but the non-continuous monitors require a certain series of operating conditions before they will set - and you can't do a complete OBD II test unless all of the monitors are ready.

To set the converter monitor, for example, the vehicle may have to be driven a certain distance at a variety of different speeds. The requirements for the various monitors can vary considerably from one vehicle manufacturer to another, so there is no "universal" drive cycle that will guarantee all the monitors will be set and ready.

As a general rule, doing some stop-and-go driving around town at speeds up to about 30 mph followed by five to seven minutes of 55 mph plus highway speed driving will usually set most or all of the monitors (the converter and EVAP system readiness monitors are the hardest ones to set). So if you're checking the OBD II system and find a particular monitor is not ready, it may be necessary to test drive the vehicle to set all the monitors.

The Environmental Protection Agency (EPA) realized this shortcoming in current generation OBD II systems. So, when it created the rules for states that want to implement OBD II testing in place of tailpipe dyno testing, it allows up to two readiness flags to not be set prior to taking an OBD II test on 1996 to 2000 vehicles, and one readiness flag not to be set on 2001 and newer vehicles. You can use the AutoTap OBDII scantool to check that your readiness flags are set before having your vehicle emissions-tested. This can save you the aggrevation of being sent off to drive around and come back later.

Some import vehicles have known readiness issues. Many 1996-'98 Mitsubishi vehicles will have monitors that read "not ready" because setting the monitors requires very specific drive cycles (which can be found in their service information). Even so, these vehicles can be scanned for codes and the MIL light without regard to readiness status. On 1996 Subarus, turning the key off will clear all the readiness flags. The same thing happens on 1996 Volvo 850 Turbos. This means the vehicle has to be driven to reset all the readiness flags. On 1997 Toyota Tercel and Paseo models, the readiness flag for the EVAP monitor will never set, and no dealer fix is yet available. Other vehicles that often have a "not ready" condition for the EVAP and catalytic converter monitors include 1996-'98 Volvos, 1996-'98 Saabs, and 1996-'97 Nissan 2.0L 200SX models.


Again drive your car for a week or check everyday and they will evetually return to "Passed". There are a few A4 OBDII Rediness Flags that are not monitored at all, thus they never activate as Passed.