Permanent DTCs

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Permanent DTCs

techton
  Soon, vehicles with permanent DTCs may be cominginto your shop for repairs.  These are new, emission-related DTCs that can't be erased from  PCM memory by using the scan tool, or disconnecting the battery.  They are non-volatile, which means that keep-alive memory is not needed for them to be a factor.

  This was purposefully done, because the purpose of the permanent DTC is to ensure that if a monitored system fails, then it must be repaired properly, and paases a readiness test, before it will clear the monitor.  As posted earlier, at least by the introduction of the DAD and plug and play, changes in the status of readiness monitors means that only one unset monitor will be allowed from 96 through 99, and only the EVAP monitor can be unset in a 2000 and up vehicle.

  Beginning in the 2009 model year, some vehicles have permanent DTCs and all vehicles from 2010 and up have them.  

  This means that, for example, the catalyst fails, and is replaced, then the readiness monitor for that component must run and be completed without incident for the monitor to set ascompleted.

  The difference is, setting the monitor on a vehicle with permanent DTCs is done differently.  The first approach is to run a Universal Trip Drive Pattern (unused in pre-2009 vehicles).  This involves clearing all the DTCs so that only the permanent DTCs are left.  Ignition key on, start the vehicle, and let it idle for at least 30 seconds.  Then, without cycling the key, drive the vehicle at least 25 mph or faster for at least 5 minutes.  Allow the vehicle to idle at least 30 seconds without shutting it off.

  After seeing this drive pattern, the PCM clears the code, since it can verify that the problem has been fixed and did not reoccur.

  If you don't want to do this, you can perform the specified trip (not drive cycle - trips are performedto set one monitor, drive cycles are designed to set them all) to verify successful completion of the repairs.  This means that you have to research code enable criteria, because each manufacturer and powertrain is different.  Then you will have to run three, not one, trips to clear a permanent DTC.  Takes longer, and research is needed, but will accomplish the same thing as the UTDP.

  In any event, knowing that these codes are cleared differently may save you some time and aggravation in completing emission repairs with the intent of successfully passing the test.  
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This post was updated on .
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Re: Permanent DTCs

techton
Barry:

  Permanent DTCs were implemented because of persistent feedback from all states that have an I/M progran.  Currently, 22 states have an I/M progran, and only 2, Calif. and Colorado, have the dyno set-up, and not plug-and-play, but we are coming into the fold in early 2014.
 
  Past experience from other states have shown that there are loopholes in readiness status, and these are being exploited by shops and consumers.

  Calif. smog check allows up to 2 unset monitors.  It is considered too burdensome to require all the monitors to be completed before the vehicle can pass.

  What the EPA, as well as the Calif. Air Resources Board, are concerned about is that if a monitor detects a fault, and a DTC is set as a result (all DTCs that set a check engine light are emission-related), that the root problem is fixed before a smog cert. is issued.

  Beginning in the 2010 model year (phase-in is up to the manufacturers, so some of the 09 vehicles are equipped, some are not), any DTC that is commanding the MIL on must be logged in as a permanent fault code.

  Permanent fault codes are stored in NVRAM (Non-Volatile Random Access Memory), which means they survive clearing with a scan tool (Mode $03), or loss of KAM from battery disconnect. Permanent fault codes can only be erased by the Diagnostic Exectutive (Chrysler calls him the Task Manager) in the PCM.

  Mode $0A (Mode 10) was created, with NVRAM, to store these permanent codes.  Memory storage capacity must store the data from up to 4 codes, as well as misfire and fuel trim data.

  So what this means is that vehicles must be repaired properly, and the permanent codes cleared properly.  The dilemma that the EPA and Calif. authorities faced is how much more it will cost the consumer to clear the codes, and run the monitors, since some drive cycles can take up to 40 hours of driving.

  The UDTC was designed to cut down on the burden of reaching code-enable criteria.  As a fallback, we can research the proper criteria for running a trip, and do those, but so far the UDTC is recommended as a first step.

  Actual reports from field technicians will determine if the UTDC will work.  It is supposed to.

  Time will tell.  It always does.

Techton  
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Re: Permanent DTCs

Frank
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So after you properly clear the permanent code does this stay stored in the vehicles memory or is it permanently gone?
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Re: Permanent DTCs

smog man
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This is a good thing, especially if you smog a lot of car lot cars, that sit with dead battery's.
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Re: Permanent DTCs

Johnnybeme
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Great information, I vote UTDP! Should have been in my update class!!!!!!

JM
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No One
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well well well looks like we are finally here.
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Re: Permanent DTCs

Best Answer I Can Give
 Should have been done from the START.  1996 OBDII
Interesting that when you TELL the TRUTH, people get upset. Plus some people can NEVER admit when they are WRONG.
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Re: Permanent DTCs

2002
I have a customer with a 2010 Toyota Rav4 that failed for permanent code. They drove it over 200 miles and have over 20 warm-up cycles since cleared and no light has came back on with monitors all set. It STILL failed for permanent code.

According to BAR if those two criteria are met the OIS will ignore the permanent code. #10 on this site
https://www.bar.ca.gov/Industry/Industry_Resources/Permanent_Diagnostic_Trouble_Codes.aspx

Anyone experience this? I called my local bar office and they had no idea what permanent code was...
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Re: Permanent DTCs

dcf1ver
2002 wrote
I have a customer with a 2010 Toyota Rav4 that failed for permanent code. They drove it over 200 miles and have over 20 warm-up cycles since cleared and no light has came back on with monitors all set. It STILL failed for permanent code.

According to BAR if those two criteria are met the OIS will ignore the permanent code. #10 on this site
https://www.bar.ca.gov/Industry/Industry_Resources/Permanent_Diagnostic_Trouble_Codes.aspx

Anyone experience this? I called my local bar office and they had no idea what permanent code was...
What is the code?

Did you verify the mileage driven and warm up cycles in mode $01 or are you going by their word?
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Re: Permanent DTCs

BasicTech678
dcf1ver wrote
2002 wrote
I have a customer with a 2010 Toyota Rav4 that failed for permanent code. They drove it over 200 miles and have over 20 warm-up cycles since cleared and no light has came back on with monitors all set. It STILL failed for permanent code.

According to BAR if those two criteria are met the OIS will ignore the permanent code. #10 on this site
https://www.bar.ca.gov/Industry/Industry_Resources/Permanent_Diagnostic_Trouble_Codes.aspx

Anyone experience this? I called my local bar office and they had no idea what permanent code was...
What is the code?

Did you verify the mileage driven and warm up cycles in mode $01 or are you going by their word?
same make sure u verify a lower grade autel or centech scanner works just go to live data and scroll down it will show miles since last reset and warm up cycles since last reset
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Re: Permanent DTCs

No One
In reply to this post by 2002
2002 wrote
Anyone experience this? I called my local bar office and they had no idea what permanent code was...
God damn I love the BAR
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Re: Permanent DTCs

No One
In reply to this post by BasicTech678
BasicTech678 wrote
dcf1ver wrote
2002 wrote
I have a customer with a 2010 Toyota Rav4 that failed for permanent code. They drove it over 200 miles and have over 20 warm-up cycles since cleared and no light has came back on with monitors all set. It STILL failed for permanent code.

According to BAR if those two criteria are met the OIS will ignore the permanent code. #10 on this site
https://www.bar.ca.gov/Industry/Industry_Resources/Permanent_Diagnostic_Trouble_Codes.aspx

Anyone experience this? I called my local bar office and they had no idea what permanent code was...
What is the code?

Did you verify the mileage driven and warm up cycles in mode $01 or are you going by their word?
same make sure u verify a lower grade autel or centech scanner works just go to live data and scroll down it will show miles since last reset and warm up cycles since last reset
This. Did you verify with a scanner??
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Re: Permanent DTCs

2002
Yeah I plugged the vehicle to my BAR97 and ran diagnostic. Miles since cleared was like 270, and warmups since cleared was 21. According to the site if those two are met with monitors set it should bypass any permanent codes.

The code was for Mass Air flow circuit. Can't remember the exact #. P01xx

All the bar rep said was the obd system must not think it's fixed. And to take it to the dealer
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Re: Permanent DTCs

2002
I've had customers fail for permanent codes before. I tell them to drive 200 miles and do 15 warmup cycles. And when they come back they have always passed. First time I've seen one not pass
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Re: Permanent DTCs

BasicTech678
2002 wrote
I've had customers fail for permanent codes before. I tell them to drive 200 miles and do 15 warmup cycles. And when they come back they have always passed. First time I've seen one not pass
send to reff customer should not need a "repair from a dealer"
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Re: Permanent DTCs

dcf1ver
In reply to this post by 2002
2002 wrote
Yeah I plugged the vehicle to my BAR97 and ran diagnostic. Miles since cleared was like 270, and warmups since cleared was 21. According to the site if those two are met with monitors set it should bypass any permanent codes.

The code was for Mass Air flow circuit. Can't remember the exact #. P01xx

All the bar rep said was the obd system must not think it's fixed. And to take it to the dealer
Bar Reps are smooth brains(for the most part) Id send it to the Ref,since you verified the criteria was met.
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Re: Permanent DTCs

none
In reply to this post by 2002
I would use a scan tool and check all the modules.

I don't know about 2010 but I know the 2004 RAV4 had a separate transmission module that would store P series fault codes.

I think the scan tool will give you a choice of module 8 and 9. It has been a really long time so I could be off with those numbers.
Good judgement comes from experience. And experience? Well that comes from poor judgement.
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Re: Permanent DTCs

BasicTech678
none wrote
I would use a scan tool and check all the modules.

I don't know about 2010 but I know the 2004 RAV4 had a separate transmission module that would store P series fault codes.

I think the scan tool will give you a choice of module 8 and 9. It has been a really long time so I could be off with those numbers.
yes what ever module has the permanent code will be the one he wants to check mileage and cycles