Hi there,
Is there a "sticky" or manual which shows what each code type actualy means:
Eg
Permanent - No MIL and never goes away
Current ???
Pending???
Old ???
History???
Looking to find out how serious each type is?
Thanks
Printable View
Hi there,
Is there a "sticky" or manual which shows what each code type actualy means:
Eg
Permanent - No MIL and never goes away
Current ???
Pending???
Old ???
History???
Looking to find out how serious each type is?
Thanks
Current code means that it's active and the reason for the check engine light.
Pending codes can happen if it needs more than one failure to make the SES light come on. Atleast that's how I understand it.
Old/History is kind of a given, they are codes that happened in the past. Be it pending or current codes that are no longer an active fault.
Current and pending codes are the most important. Obviously the permanent code is just in the code description when you look at them in the VCM scanner.
Thanks for that, That's what I thought. I find it strange that HPT does not have this in a user guide?Quote:
Originally Posted by 5FDP
What are Permanent Diagnostic Trouble Codes?
Permanent Diagnostic Trouble Codes (PDTCs) are very similar to regular Diagnostic Trouble Codes (DTCs). However, unlike regular DTCs, they cannot be reset by disconnecting the vehicle’s battery or cleared using an On-Board Diagnostic (OBD) scan tool. The only way to clear a PDTC is to fix the underlying problem with the vehicle that originally caused the PDTC and its corresponding DTC to set, and then allow the vehicle sufficient drive time to re-run the monitor that identified the problem in the first place. When the monitor runs without identifying a problem, the PDTC will clear itself.
Unplugging the vehicle’s battery or using a scan tool are techniques sometimes used to clear OBD information for a vehicle that has an illuminated malfunction indicator light in an attempt to hide the fact that the vehicle is malfunctioning. Some of these vehicles can pass a Smog Check inspection before the vehicle can re-identify the underlying problem that set the malfunction indicator light and DTC(s).
The new criteria will apply to model-year 2010 and newer vehicles that support PDTCs.
Basically to clear a PDTC you will need to complete the portion of a drive cycle that verifies proper function of system, sensor, or calculation that would cause the code to set.
ThanksQuote:
Originally Posted by TheMechanic
I would like to resurrect this thread because I have questions.
First; I get Permanent codes (per HP) and they go away on their own almost instantly if fixed, or I can clear them with a scanner. Those ones don't worry me but I do wonder what Permanent means.
I also have, per HP; SES, Pending and Current. Again, wth do they mean?
How can I be sure a code is really gone, meaning enough to pass a smog check? Because I cleared mine, nothing pending or otherwise, and failed smog thanks to a "history" of a code. When I got home, eng still running, I scanned with Xentry, zero codes. Autel, zero codes. So how the F can the smog machine see it and I cannot?
The smog guy said I gotta drive it 200 miles to clear that. I asked; 200, or is it really 100 and people just say 200 to be sure? Or is it really xx time and 200 oughta cover it? He didn't know. Would be nice to be able to see if/when this history is gone before I waste more $.
Say I had a code that needs to see more than one instance to trigger a CEL, lets say three occurrences. If there is just one or two occurrences and says Pending or whatever, but No CEL, can I pass smog like that?
Calif claims to do checksum checks, yet I read lots of people online saying they passed with incorrect checksums. Others saying they failed checksum for bs reasons, like the car was stock and they don't why. So it seems as if some places check and some do not? I was unable to find anyone that said they had a tune and failed.
My problem code this time is P2610, which imo has nothing to do with anything, but it will not go away and makes a CEL. No it's not the ecu. So lets say said code were turned off, you can see my issue with checksum, or is it an issue at all?
Thanks :)
Let's go through this one at a time.
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Emissions Related DTCs
Action Taken When the DTC Sets – Type A
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
Action Taken When the DTC Sets – Type B
The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
The following applies to misfire DTCs:
If the control module detects a low level or an emission level misfire condition during 2 consecutive trips, the control module illuminates the MIL.
If the control module detects a high level or catalyst damaging misfire, the control module flashes the MIL at a rate of once per second.
If the control module detects a misfire during 2 non-consecutive trips, the stored conditions are compared with the current conditions. The control module illuminates the MIL when the following conditions occur:
The engine load is within 20 percent of the previous test that failed.
The engine speed is within 375 RPM of the previous test that failed.
The engine coolant temperature is in the same range of the previous test that failed.
The following applies to fuel trim DTCs:
If the control module detects a fuel trim condition during 2 consecutive trips, the control module illuminates the MIL.
If the control module detects a fuel trim condition during 2 non-consecutive trips, the stored conditions are compared with the current conditions. The control module illuminates the MIL when the following conditions occur:
The engine load is within 20 percent of the previous test that failed.
The engine speed is within 375 RPM of the previous test that failed.
The engine coolant temperature is in the same range of the previous test that failed.
Conditions for Clearing the MIL/DTC – Type A or Type B
The control module turns OFF the MIL after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Non-Emissions Related DTCs
Action Taken When the DTC Sets – Type C
The control module stores the DTC information into memory when the diagnostic runs and fails.
The MIL will not illuminate.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
The driver information center, if equipped, may display a message.
Conditions for Clearing the DTC – Type C
A current DTC Last Test Failed clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
Clear the DTC with a scan tool.
P2610
The intake air temperature is between −40 to +125?C (−40 to +257?F).
DTC P2610 runs on ECM Power Down.
Do you have battery power connected to the ECM when powered down?
So 'No MIL Light' in HPT-speak means Type C?
I believe you are correct. Never thought of it that way but now that makes sense.Quote:
Originally Posted by blindsquirrel
Thanks Mechanic :)
Lots of info but still confusing. I assume that's generic info? Because some of does not apply to my current car.
Not sure what a drive cycle is but I would assume from a certain cold temp to a certain hot temp? Or maybe it's xx miles after a start? What I see is some codes trigger when the ign is turned on (no start), others need the eng running to see the code. Sometimes it needs the O2's to kick on before it trips a code.
Then for the code to go away on its own, same deal. If it tripped on ign on only, and if fix it, then ign on and it's gone. At least the times I can recall it does that, but I don't keep records of every code, that would be a massive book. I have codes almost every day, sometimes more than I bother to count but probably 25 or so. If I get a bunch they are mostly U codes. P codes usually just one or two. The P codes are gone next time I look so I don't bother clearing them, and I look before every shutdown, sometimes more.
If I leave a sensor or something unplugged by accident, or on purpose, and get a code when I turn the ign on. I plug it back in, turn the key on and code is gone.
Another is I used to have a swtich to kill a solenoid feeding the ECU, because it was active 100% of the time, ECU was hot 24/7 and killing my batt. If I forgot to turn it back on and tried to start it, instant CEL and bunch of codes, which stayed there after start. I'd wipe those manually because the CEL bugs me, never tried to see if they go away on their own over time.
I've never had a Fuel Trim code, ever. Even when the trims are so far off it kills the O2 sensor and trims altogether. I guess it goes open loop? If I didn't monitor it with HP I'd never even know it happens because there are no codes. Simply cycling the ign resets it. Or, if fuel is so far off the car barely runs, or not at all, no codes of any type.
Part throttle overboost, which is my fault due to tinkering, will kill the turbos but no codes. Simply cycling the ign resets it, which I can do on the fly with the key, but Keyless Go I have to come to a stop to do it, which is super annoying. I HATE safety features.
I've had full throttle overboost codes when I didn't actually overboost. Actual overboost usually does not trigger a code, but sometimes it does. Code or not, overboost has never killed the turbos.
I did have a misfire code when I had a bad coil, but I've had far more misfires since then with no codes, but those were fuel misfires. So my guess is as long as the coil current looks good, it thinks it fired.
Obviously the ECU just does what the programming says. Imo the programmers are not good enough at their jobs, and I pay the price for their incompetence. The price is failed smogs when nothing is wrong, and getting rid of perfectly good cars as a direct result.
Not sure why the intake temp question, but well within those #'s. Even when the Ign is off the Int temp reads and changes as it sits there. When I mentioned the ECU not powering down and killing the batt, that stopped the moment the Keyless Go died last November. No codes for that btw, and per Xentry Keyless Go is 100% good, yet it is not. So now that the ECU powers down, which I assume powers down normally, I believe there is some tiny bit of current because it is very slightly warmer than the eng when sitting for days. When I turn the eng off I can hear things being cycled for a few minutes. If it's been sitting for a while and I open the door, I can hear stuff kick on and it draws a lot of current. I assume those things are controlled by the ECU but just a guess.
I don't believe there is a fix for the P2610. I was only able to find two options online; reset car or replace ECU. Well, what happens when you do both and it's still there?
My jinx with any electronic car is a CEL just before I need a smog check. Whatever the code might be, it cannot be fixed. The code may be real, but usually they are not and you can't fix what ain't broke.
I have never fixed a single one that appeared and ruined a smog check. I can sometimes trick it, or maybe get lucky and the code will go away just long enough to pass smog, but the code is forever and in many cases I have to get rid of the car. In one case I just drive it for years anyway, I just took the plate off.
My current car took six months of experimenting to figure out how to trick it into passing, which I did a week ago. The CEL reappeared right the after the smog check, so very close call. That was my fourth attempt btw.
Never heard of the 40 warmup cycles thing. Thank god that one isn't true or there's no way in hell I'd ever pass a smog, in any car I've ever had.
I did answer one of my questions: Calif does do checksum checks. I have the printout of a failed smog attempt to prove it. Apparently they don't do it to all cars because the smog guy, doing nothing but smogs for >10 years, said he's never seen that before. He said he's done tuned cars too, so it's just lucky me I guess.
Still don't know what Permanent, SES, Pending and Current mean.
I would think Pending is a first incident? Yet it may stay there for >ten incidents.
Current is currently happening? Yet it can be currently happening but not Current, or Current and not currently happening... So the descriptor Current is not accurate at all.
Permanent is not permanent, so again no clue what it means.
SES, per the internet, means "Service Engine Soon", but the CEL is already on and usually when I get them it's for a non engine issue. I also rarely see this, so what exactly triggers it? Eg I could have a code for weeks, like P2610, then one day it'll add SES to the list. Or sometimes the moment a code appears the moment the Ign is turned on, it's SES. There must be a chain of events that trigger it, all these, but how can I find out?
Still no idea where the history of codes is hiding.
Code set criteria, and especially all the different readiness monitor requirements, are specific to each car. You need the GM service manual info for your car if you really want to understand what it needs to see.Quote:
Originally Posted by chevota
It's not GM, but I have tried to find anything car specific and struck out. Basically what I deciphered myself is all the info I have.
The readiness I'm not worried about, never had an issue with those on any car ever. Codes, on the other hand, every car ever. Helps to know all you can about your enemy if you want to beat him.
You sometimes have to pay money to get the hood info. Most oems have some sort off subscription service to get to the model specific service manuals. But I don’t know if that is universal.
I have the factory data, but it doesn't cover details. It's a repair manual for a grunt that says xx code means you should check plugs xyz and if that fails replace whatever part, the end. Those manuals are ok for simple issues, but generally they're useless. For complicated issues I need more than the dealer can provide.
I've had many issues where I needed far more info than the dealer can help with, but my current issue is code P2610. There is virtually no information on why it exists or how to fix it. I have more info now than I did 8 months ago, but I want to know exactly what conditions trigger the code, CEL, and why. What does the ECU want to see that it isn't seeing? Or maybe seeing that it should not see? Where does this data come from and where does it go? What data is is it? Binary bit on the CAN? 12V On/Off? 5V On/Off? Maybe it's actual data? Is it from the CAN or a direct wire? At what moment is the data sent? Or perhaps it's continuous? So many questions and so difficult to get the answers. With more information I might actually be able to fix it, or simulate it so it goes away.
Knowing the how, what & why of the codes and the associated descriptors will help with understanding and passing smog checks. Knowing how to access the history of codes would be very valuable. And what else is the smog machine looking at? Checksums, SCN, CVN? If a checksum, what kind exactly and of what? I want to go into a smog check knowing it's ready, because if you do the wrong thing, or fail the wrong way, you could easily end up at the state referee. You do not want to go to the referee...
Sure I could just sacrifice my car and get another, but I've had to do that many times and I'm sick of it. Not to mention the expense and risk involved. If you don't live in California you may not understand, but it's not simple and risk free.
I feel people should have the right to repair their own cars and this is required information to do that. That right will be law soon, but I do not believe I will get the information I want as a result of it.
Well you still haven’t actually named a vehicle but maybe it’s just GM that gives good details on what is going on for codes.
You're looking in the wrong place if you're going straight to the DTC's page and expecting everything about how the whole system works to be there. In GM-speak, you'd look at the Description and Operation section for that subsystem, or, even though you say it's not relevant, the pages for I/M Readiness and Service Bay tests.