Quote, originally posted by mnshewch » P1296 - Most replies indicate that this is either a bad Engine Coolant Temperature (ECT) sensor -OR- a bad thermostat. Engine appears to already have a "Green-Top" but I bought a new one ($13) and intend on installing myself.
Do that first; replace the CTS, clear out the fault codes with a VAG-COM.
Quote, originally posted by mnshewch » I'm not sure why the code P1296 appeared twice on the EI report.
Because the ECU has spotted the problem two individual times.
Unlike the MK5, there's no time / date stamp associated with when the fault was triggered.
Quote, originally posted by mnshewch » P0420 - Most replies indicate that this is either a bad cat -OR- bad O2 sensors. I have also seen remarks about MAF and O2 sensor spacers.
Again, both the O2 sensors can be checked with a VAG-COM.
Data-logging the measuring blocks of the O2 sensor voltage during RPM's and load will tell you alot.
Quote, originally posted by mnshewch » I'm at the point where I want to attempt this myself and try to save as much money as possible. My general engine knowledge is pretty poor... but my DIY skills are decent. Any tips?
Get hold of a local owner with a VAG-COM to help you properly test, diagnosis and isolate your catalyst efficency problem.
Also, how did you fail you emissions? Do you have burn part-per-million (PPM) readings?
How was your CO, CO2, NOx, HC and burn readings?
Quote, originally posted by mnshewch » *Here in Georgia, we can get an emissions re-test for free at same location as original (within 30 days).
Same with Colorado; I just went through a catalyst replacement after failing twice on a bad cat... there are tall-tail warning signs.
Quote, originally posted by mnshewch » And then, after I make repairs, how long do I have to drive it to clear codes?
"Readiness" of the ECU takes a handful of cold- and warm-starts.
You can override and set readiness instantly with a VAG-COM to confirm if repairs are good.