Computer won't set readiness- now what?

[pgoes]

Hi all- I've been mostly lurking here for a couple years. I still have an 04 wagon, now with 156000 miles. It's been geared, had the tranny replaced, and had most of the usual faults that the Passat TDI is known for.

Now I can't smog & re-register the car because the computer reports that the EGR won't pass readiness. It was initially traced to a bad thermostat that didn't allow the temp to get high enough. But after replacing that the computer still will not reset, reporting that the EGR is not ready.

I have a good mechanic (AVS in Berkeley, who have done most major work); and he and I have both followed the published steps to reset readiness (warm up, idle, 2 minutes at 60 MPH/1800RPM, coast down, etc.). Still not ready. Since it is still at the shop I cannot quote the exact values or verbiage that the reports give. Its been in the shop going on 2 days now and he's at a loss-- is checking wiring, sensors, whatever may be connected.

Can anyone here in the community suggest a productive direction to investigate? or anyone had a similar problem?

 

[imo000]

Sometimes all it needs is to be driven for a few days. If it takes a while for the first adyness to complete then, the results are borderline and the ECU needs to make multiple tests to know if it good enough to pass. Did you clean the EGR valve? Also, the problem might have not been only the thermostat and you have more than one problem.

 

[pgoes]

Good suggestions, but Idont think they pan out. I've logged way over 500 miles since this started, in all kinds of driving, and driving the the published reset procedure. I pulled the egr and its clean- I sprayed it out with carbo cleaner too. Checked & cleaned all the wiring to tHe egr too... and all that was before I gave it to the mechanic.

 

[imo000]

Have you logged any significant miles since your mechanic did the work?

 

[oilhammer]

You can easily watch EGR operation with a scan tool. I've seen some BHWs take a little while to set that readiness, too. Not sure why.

But even without a scan tool, you can listen for the engine idle pitch to change after a hot idle of a couple minutes without touching the accelerator. The EGR is normally ON at idle, duty cycled according to what the ECU wants it to be based off of MAF input. After a few minutes of idling (maybe 3 or so) it will shut the EGR off, and the engine will get noticeably noisier if you are listening for it.

If you are watching the MAF values with a scan tool, you'll see at during idle while the EGR is still on, the actual and requested MAF *should* be tracking together very closely. Maybe 250 or so. When the EGR shuts off, the actual will jump up to 450 or so. Blip the accelerator, and it will turn the EGR back on again, and the actual will go back to requested.

If the MAF isn't working correctly, the EGR can't work correctly. Some cars allow a Basic Settings for the EGR, too, but it escapes me at this time if the BHW does or not.

 

[pgoes]

So, back from the shop; not fixed and smogged yet, but at least a possible reason---
They found that the ECM/ECU has a different version # from spec, possibly from an RC chip tune I had done about 4 years ago. That was erased (I thought) by a later recall, I think for glow plugs.

The shop had another '04 Passat TDI and compared my data with it.

The 'standard' ECU version is
R4 2,0L EDC G00AG 0314

My ECU shows
RC s02c EDC G00AG 0314

This may be causing the MAF spec to not comply with the norm, preventing the readiness setting. ? At least that's the notion.

My readings:

Basic Functions - EGR
861 / min engine speed
850.0 mg/str Mass Air Flow (specified)
465.0 mg/str Mass Air Flow (actual)
100.6% EGR duty cycle

The other 'normal' unchipped car shows:
Basic Functions - EGR
861 / min engine speed
345.0 mg/str Mass Air Flow (specified)
350.0 mg/str Mass Air Flow (actual)
79.3% EGR Duty Cycle

So the EGR is increasing the boost at idle? My shop recommends replacement of the ECU.

I think Tomas Sport tuning did the chip tune at a GTG. Maybe they can re-flash the ECU?
If I have to get a new one any recommendations from where? Ebay??

 

[1854sailor]

Just checked Bentley and they have procedures for Setting Readiness for every Passat engine EXCEPT the BHW. Go figure?

The "RC" prefix in your version is Jeff's "signature". I have to agree with oilhammer that there's something else going on as I have a RC tune and readiness is not a problem.

You do NOT need a new ECU. Give Jeff a call and try cleaning the EGR valve, then find a shop that knows these cars. Matt Phelan (Matt98-AHU on the forums) just opened a new shop in San Anselmo.

 

[imo000]

There is a discussion on the Ontario forum about tunes and systems not getting ready. These are posts that state if the car has a tune and if the fees are ever cleared, the EGR and some other deleted systems will never go into a ready state again. Sounds like you have exactly that. Contact the tune vendor and ask fo assistance.