Since my Hybrid Tahoe is on the verge of being 5 years old, emissions testing was required here in the Phoenix metro area to renew the registration.

It Failed, three times.

Mind you not from excessive emissions but for vehicle computer errors.

The first fail was "malfunctioning MIL", it certainly appeared to work correctly but the OBD II system said there was an issue so that was that. The dealer cleared the fault and reprogrammed the computer.

The second fail was "OBD not ready" EGR not ready. a "drive cycle" did not solve this, I drove it for a week, it would not "get ready" for testing. The dealer cleared the code, reprogrammed again, and replaced an engine module(one of many apparently).

The third fail was "transmission fault". Back to the dealer...replaced auxiliary transmission pump module(not the pump it self) and module harness, the harness was somehow damaged and module was shorted.

There was never any driveability issue or indication there was any issue.

It did finally pass today.

This was especially frustrating because I had always thought the emissions testing here was a sham. I had brought Diesel's there that completely filled the entire building with smoke to the point it looked like the place was on fire and they still passed. I brought a race car on a trailer that was clearly not street legal(but still has registration) and you practically needed a gas mask to stand near and that passed(they did make me take it off the trailer).

 

did they do the sniff test? or are those errors found on the ECU? how many miles(ok if not revealed). synthetic oil used?

 

No "Sniff test" , they only do the sniff test on older than 1996, Diesel's, and heavy duty trucks. (and I think that do a particulate opacity test for diesels)

for 1996 & newer They just plug in to the OBD II port under the steering wheel. I guess that tells them everything they need to know.

110K miles.

I Always use "real" synthetic oil, produced with Fully synthesized group IV & V base stocks, not pseudo-Synthetic hydro cracked (Mobil 1) that use group III+, PAO, AN & POE base stocks. Mobil 1 is still a very good oil, I just try not to patronize companies that manipulate facts to sell a product to an unsophisticated consumer, and I prefer using authentic 100% true full synthetic.

Blackstone oil analysis every 7-10K.

I scoped the cylinder bores a few months ago to play with a new tool and they look like brand new, I can still see the cross hatching on the cylinder walls which is amazing @ 110K miles.

It clearly wasn't an issue with the actual emission output of the Tahoe, They gave me a very detailed report, the issue was with the OBD II computer and associated modules, there were stored faults that didn't trigger any warning lights or cause any driveability issues.

 

So, what is your true synthetic oil? German castrol which I use in my range rover but is hard to find and only dealer provided castrol professional or amsoil? I'm not sure but the extended performance version is the real group IV base stocks. edit: just checked and mobil 1 EP is GF-5

 

I would ask for more evidence on that EGR not ready. The 2-Mode LFA and LZ1 engines do NOT have an EGR valve to be "not ready".

No amount of reprogramming and drive cycling can fix something that was never there.


My suspition is that they are not quite equipped to deal with hybrids.

 

I believe German Castrol is still "true" synthetic that uses only group VI and V base stocks. In fact German oil standards and Castrol were two of the factors in the whole legal mess that started with Mobil suing castrol(and I believe shell?) about their different formulations , the judicial system sided with castrol and I guess mobil(and others) said to hell with it, if it's legal in the US to call Group III base stock synthetic and it's less expensive that why not use it.

German standards(and several other nations but not the US) require that synthetic oil use only group IV or group V base stocks. This is why there are usually two(or more) formulations for each brand. German synthetic castrol is a different formulation than domestic synthetic castrol and more expensive.

Mobil 1 may have changed back to a "true" synthetic using group IV or V base stocks, I'm not sure as I haven't researched it in a few years. Oil formulations are constantly changing.

I use Schaeffer oil which is a True synthetic oil using group IV and V base stocks. Other oils I believe are true synthetics are Motul, any German formulation(castrol), Amsoil, Torco, royal purple, schaeffer, and many others. since formulations routinely change it's best to read the current data sheet for any oil to see what base stocks and additive packages they use.

If you want to be bored to death reading about oil check out this forum www.bobistheoilguy.com

 

I would tend to agree with you but these were typical lower level government employees(sorry government employees), they didn't give a crap about anything except putting their 8 hours in and acting like robots, 10 times worse than the DMV.

The fail report they gave me did say "EGR not ready" but they offered no further explanation. whatever the dealer did it fixed the issue, it finally passed.

I also starting to get the impression that as time goes on and the Tahoe Hybrid gets older and the issues get more complex, the dealer(and perhaps the manufacturer) has less experience on how to resolve the issues. The hybrid Tahoe is somewhat rare here in the Phoenix Metro area, I can go weeks without seeing another. the same mechanic at the dealer works on mine every time, if he's not there the car waits for him to return, I'm not sure if he's "hybrid" certified if there is such a thing but he's the only one at my dealer that works on Hybrids. I have never seen another Hybrid at the dealer while I am there and it's a very busy dealer(200-250 cars serviced per day)

 

I checked the Mobil 1 extended performance and the spec says Group V. As for hybrid in the Phoenix area, aren't the police squad equipped with the Tahoe hybrid?

 

Most state mandated "emissions" testing is a complete joke. Unless they strap the vehicle to a Chassis Rolls Dynamometer and attach a real emissions bench to the tail-pipe, there is no better way to measure if the systems are working.

That's at least $500k worth of equipment or much more and an hour and a half per test with another half hour of post test analysis. Not likely.

One could probably set up a little programmable box that contains the VIN and will return a NO Codes message in CAN script to the so-called tester. Hide the real data connector up above. Cut an old one out of a junker.

It wouldn't be very hard for the Scan Gage kind of guys to do.

 

Based on the info. I found on the Exxon/Mobil website and their cryptic answers, I'm going to guess they are still using Group III hydro cracked base stocks and not PAO or group VI & V. I still think Mobil 1 is an excellent oil, there's nothing wrong with a high quality mineral oil, just don't call it synthetic.

http://www.mobiloil.com/USA-English/...Base_Oils.aspx

http://www.mobiloil.com/USA-English/..._Question.aspx



I've never seen a hybrid Tahoe police unit anywhere in Arizona, the Phoenix police Tahoes are just the regular PPV Tahoes although some of them may be natural gas, the city of phoenix is huge on natural gas vehicles.

Frankly, I don't think the Hybrid Tahoe would be the best choice as a police vehicle, it's speed limited to 99MPH, the battery pack location would make installing the cage and seat problematic, the additional police electronics would likely be an issue integrating with the hybrid electronics, no spare tire is an issue for a police vehicle, The speedometer isn't certified and it's not available with a simple basic trim set up(without leather,nav,etc.). The PPV Tahoe is a pretty robust vehicle, I was impressed when I had the opportunity to drive one.