check engine light
01-23-2013, 08:08 AM
#31
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Location: Hell was full so they sent me to NJ
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Re: check engine light
You have an M6 trans. That code definition is for an A4. Hopefully you are using Shoebox's code list:
http://shbox.com/1/Dtcs.htm
So, DTC 84 = Skip shift solenoid circuit (manual transmission)
DTC 91 = Skip shift lamp circuit
Yes, both related to skip shift. Put a 2,000 ohm resistor in the harness connector for the skip shift solenoid, and you will not get DTC 84. You should also be able to prevent DTC 91. I'll have to find the link on how to do it.
See response below.
How did you "look at the injectors"? You should be able to see the pulse width, and there is a code (DTC 18) that will set if there is an electrical fault on any one of the injector circuits. But I'm not aware of any piece of scan data that can show you an injector is plugged up, stuck or flowing the wrong quantity.
If you unplugged the MAF sensor with the engine running, that's when the code set. What you are reading is a "stored" code, not an active code. There is nothing wrong with the MAF sensor.
http://shbox.com/1/Dtcs.htm
So, DTC 84 = Skip shift solenoid circuit (manual transmission)
DTC 91 1-4 shift light fault...... I'm thinking the first two have to do with disconnecting the skip shift and light from the computer which I don't really care about.
Yes, both related to skip shift. Put a 2,000 ohm resistor in the harness connector for the skip shift solenoid, and you will not get DTC 84. You should also be able to prevent DTC 91. I'll have to find the link on how to do it.
DTC 48 mass airflow system failure.....The others I'm guessing the components are bad. While data logging I was sitting around 7 gm/sec airflow and it was going up and down smoothly while driving.
I did do a test on the maf the other day by unplugging it with the car running and it almost killed the car. Very well could be a loose connection though.
Last edited by Injuneer; 01-23-2013 at 08:12 AM.
01-23-2013, 06:17 PM
#32
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Join Date: Dec 2012
Location: Florida
Posts: 47
Re: check engine light
Thanks guys, that's good news about the maf sensor. Is there a way to see which codes are Pd like obd2 and which ones are current? When I was looking at the days log i couldn't see a pulse width but there was a line saying injectors operating 8 and then the next line said injectors operating incorrectly 0, or something close to that. That's about as much as I can see for the injectors. Oh also the knock sensor said 1529 knocks detected but during the 20+ minutes I was idling and driving the number never went up and it continuously said 0 knocks detected.
01-23-2013, 08:49 PM
#33
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Location: Hell was full so they sent me to NJ
Posts: 70,648
Re: check engine light
You are seeing the results of the electrical continuity/voltage test on the 8 injectors. That mean they are all operating electrically. It does not tell you how well they are flowing, whether they are leaking, etc. If it switched to 7 operating, 1 not, you would get DTC 18.
The "knock count" field is not actually counting individual "knock" events. It is a calculated field, based on the PCM identifying operating conditions that MIGHT produce knock. The field starts at "0" when you clear the PCM, and then the PCM continually increments the number upwards, until at reaches a little bit more than 64,000 and the PCM resets it to 0. The actual number in that field is not important. It's how fast it is changing, and whether it is causing the PCM to retard the spark timing. You reset the PCM, and it reset to 0. Then it incremented upwards as you started the engine. It isn't unusual to see the number increase by a couple thousand at startup.
Were you getting a reading of any knock retard during the period it was idling? If not, the PCM was not doing anything in response to the knock count. If the PCM had received an indication of knock from the knock sensor, then it would also respond to a rapidly incrementing knock count to retard the timing.
If you aren't getting any indication of knock retard, you don't have a knock problem.
The "knock count" field is not actually counting individual "knock" events. It is a calculated field, based on the PCM identifying operating conditions that MIGHT produce knock. The field starts at "0" when you clear the PCM, and then the PCM continually increments the number upwards, until at reaches a little bit more than 64,000 and the PCM resets it to 0. The actual number in that field is not important. It's how fast it is changing, and whether it is causing the PCM to retard the spark timing. You reset the PCM, and it reset to 0. Then it incremented upwards as you started the engine. It isn't unusual to see the number increase by a couple thousand at startup.
Were you getting a reading of any knock retard during the period it was idling? If not, the PCM was not doing anything in response to the knock count. If the PCM had received an indication of knock from the knock sensor, then it would also respond to a rapidly incrementing knock count to retard the timing.
If you aren't getting any indication of knock retard, you don't have a knock problem.
01-23-2013, 10:31 PM
#34
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Join Date: Dec 2012
Location: Florida
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Re: check engine light
No there was no timing retard showing on the program so I figured I didn't have a knock problem. The program didn't have the injector pulse apparently so I'll try to get tuner cat and use that. One problem with the aldl drivers is I had to change the com port, to port #1 to get any program to read and pcm comm was the only one I got to work. I changed from com port 16 to com port 3 on the laptop as the directions said then took a shot in the dark for com port 1. If you guys have any ideas to get the other programs to work let me know. I'd like to use freescan or like I said tuner cat. Thanks.
01-27-2013, 08:26 AM
#35
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Join Date: Dec 2012
Location: Florida
Posts: 47
Re: check engine light
Well guys changed out the left o2 sensor and it runs like a champ. I got the right o2 sensor too to change that but might not need it right now. If it ain't broke don't fix it. Thanks for all the help on this.
01-27-2013, 08:59 AM
#36
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Join Date: Jul 2010
Location: Westminster, CA
Posts: 349
Re: check engine light
Glad it was that simple. And now you have a a code reader for the next time. As great help as this website is, if you are planning on keeping the car long term, pick up a used factory service manual set on ebay, they are about $75. Those two items are, imo, mandatory if you are going to do your own work/mod your car.
Last edited by pgerst; 01-27-2013 at 09:02 AM. Reason: added last sebtnce
08-22-2018, 04:21 AM
#37
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Join Date: May 2018
Posts: 15
Re: check engine light
UOk guys just got back from the mechanic who said he could pull the codes. He printed off some directions (probably off alldata or something) and went to work trying to jumper the 2 wires together. That lasted for about half an hour with him going back and forth many times to the office. Then he comes out with a scanner and I think ok we might be getting somewhere now. Another 45 minutes goes by and finally he backs my car out and says the problem is that I need a new pcm cause his code reader won't communicate with the pcm and he proceeds to tell me "when you jumper these two wires it will do blah blah blah". So I tell him thats not how the 94 and 95 work and he interrupts me and says basically if you know how to do it then why'd you bring it to me. So needless to say I didnt get any info i didnt already know and between that and his rude attitude I dont think I'll be going back there ever. Also, let me say I do own a hotrod and custom shop where I work on old cars with carbs and such. I did graduate Wyotech in 2002 and do know alot about cars. Basically what I'm getting at is anyone can read a computer and do what it tells them to do if they have basic reading skills like this guy. That doesn't make you a mechanic. People like shoebox and injuneer and others on here are real mechanics. I know its not possible for a person to know every vehicle and I don't expect that what I do expect is what I'm not affraid to tell my customers "i don't know and you might wanna take it to someone that can help you better than I can". Honesty goes a long way don't tell me I need a pcm but have nothing to back it up. Just tell me I thought I could pull the code but I was wrong. Sorry for the rant but I guess I'll just get the cable and do it myself. Ill let you know what codes I get.
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