73-87chevytrucks.com
General Site Info => General Discussion => Topic started by: gunrac on February 26, 2016, 06:37:44 am
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Is there a way I can retrieve my OBD II code w/o going to the parts store? Plus, looking for a decoding chart.
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obdII or obd I? obd II no obdI yes
http://forum.73-87chevytrucks.com/smforum/index.php?topic=29949.0
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Not that I could find after exhaustive search. Santa had one for me under the tree several years back. As far as codes found, I just Googled the POxxx for the specific year and model and was surprised to find similar problems for a similar vehicle and how they fixed them. Good luck, Vile has helped me on a couple of occasions where it was beyond research.
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Yes, I hit the search in here and found the OBD I, also done the google w/o insite. I did see where a Dodge has a quick retrieval process, nothing on the Chevy tho.
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OK.....I was under the impression that the OBD II, started in 92'. After another google, I read the OBD II didn't come in till 96'. I don't consider this as confirmed. I'm dealing w/my 94'. Can someone give me the proper confirmed dates on the changes. All help is appreciated......
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its hit and miss in 94 but was standard by 96
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if your plug looks like
(http://i333.photobucket.com/albums/m387/rebel_cowboy_83/Diagram/2009-10-03_182103_11_zpsf216fdaa.gif)
then its obdI
if it looks like
(http://i.stack.imgur.com/b3kaj.png)
then its obdII
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THX.........I haven't looked yet, but that will help me to figure it out quickly.
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The rounded corner trapezoid shaped J1962 jack is not just OBDII. GM used it in late 1994 & 1995 on ALDL ECMs. Vendor Option terminal 9 on the 16 terminal J1962 (OBDII) jack was used to pass the 8192 baud serial data normally found on terminal M of some 12terminal ALDL jacks.
I had a 1995 6.5L truck. I added a 12 terminal Metripack ALDL jack with A, G, & M populated from J1962 jack 5, 16, & 9 respectively. I put it next to the J1962 jack.
The pinout of the 12 terminal Metripack ALDL jack varied by year and GM nameplate.
This is my writeup on options for monitoring and reading codes from ALDL http://forum.73-87chevytrucks.com/smforum/index.php?topic=32624.0
Obviously a GM Tech II or MDI will give you the most information and they are bi-directional meaning you can send commands to controllers but we mere mortals can't afford those.
The same inexpensive laptops I wrote about for ALDL will work with $50 USB OBD II interfaces or you can use TorquePro on an Android phone or tablet with a Bluetooth adapter.
Some of the cheap Actron OBD handhelds are actually OK tools. If all you want is to pull OBD II codes and swap parts get a cheap handheld scanner. Some handheld scanners will read and show some sensor data.
BTW: People call ALDL OBD I. That is not correct. OBD I is California only between 1991 & 1995. ALDL is not OBD I but GM OBD I is ALDL.
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OK.....I was under the impression that the OBD II, started in 92'. After another google, I read the OBD II didn't come in till 96'. I don't consider this as confirmed. I'm dealing w/my 94'. Can someone give me the proper confirmed dates on the changes. All help is appreciated......
so now you know it's not OBDII but why don't you tell us specifically what you are working on?
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I got under yesterday.
if your plug looks like
(http://i333.photobucket.com/albums/m387/rebel_cowboy_83/Diagram/2009-10-03_182103_11_zpsf216fdaa.gif)
then its obdI
if your plug looks like
(http://i333.photobucket.com/albums/m387/rebel_cowboy_83/Diagram/2009-10-03_182103_11_zpsf216fdaa.gif)
then its obdI
Mine resembled this, but I think where the pin's appeared was a bit different. Will get under again today and get back w/a better description.
I did jump the A an B, it worked accordingly as described by Irish. I came w/a code 32. Not sure on this code as it is a new EGR that past the suction test before assembling. Light only came on after around 10mi. run. Then didn't come on the next day until it got to good running temp. This happened 3 days in a row.
Timing was finally set. It was a bit retard, as I could see the timing line just below the v-notch at start up w/advance wire unhooked. Went ahead and reset ECM/PCM. Have a 20mi. run today......will see if light shines again today.
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Dang lite came on......code 32 again.......I don't know? Pic of my feed.....what do I have.....+ help on the code.....
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callin my a to b......right top to left
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OK.....I was under the impression that the OBD II, started in 92'. After another google, I read the OBD II didn't come in till 96'. I don't consider this as confirmed. I'm dealing w/my 94'. Can someone give me the proper confirmed dates on the changes. All help is appreciated......
so now you know it's not OBDII but why don't you tell us specifically what you are working on?
Is it a secret or did I miss it? What are you working on?
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Thought it was mentioned......1994 Chevy Cheyenne W/T package, 305/700R ......really need help.......new EGR , cleaned out a lot of crap in manifold, when doin valve job ....what do I need to look at now?
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whats it doing?
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Right, is there a drivability issue or just the EGR code coming up?
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whats it doing?
Really is not acting up in anyway, just the idea that the _Check lite only comes on after good running temp. is reached._ Code 32, is what it shows when jumping A+B on the pinout as I understand it. Not sure if I got a bad EGR. It did pass the vac test before installing. Vacuum line is good. The ECM along w/IAC are also new. The truck runs real good, no issues at all.
This is my reason for concern:
I'm still not sure what caused the bent valve issue. I'm leaning toward the old EGR being bad w/the manifold being plugged pretty tight w/carbon. Most of that was on right side, but #7 intake valve give up. The plugs showed the engine was running very lean.
I just did get a 100 mi. on it since the valve job. Don't believe it has enough run time to really show anything by checking plugs, but I'll pull a couple today.
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Circuit Description:
The ECM operates a solenoid to control the Exhaust Gas Recirculation (EGR) valve. This solenoid is normally closed. By providing a ground path, the ECM energizes the solenoid which then allows vacuum to pass to the EGR valve.
DTC 32 Will Set When: The ECM monitors EGR effectiveness by de-energizing the EGR control solenoid; thereby, shutting "OFF" vacuum to the EGR valve diaphragm. With the EGR valve closed, and O2S fluctuating normally, short term fuel trim counts will be greater than they were during normal EGR operation. If the change is not within the calibrated window, a DTC 32 will be set.
The ECM will check EGR operation when:
•Vehicle speed is above 45 mph.
•Engine vacuum is between 15 and 60 kPa.
•Throttle angle between 6 and 30%.
•No change in throttle position while test is being run, max 4%.
•EGR on threshold 98%.
Action Taken (ECM will default to): The Malfunction Indicator Lamp (MIL) will illuminate.
DTC 32 Will Clear When: Conditions for fault are no longer present and Tech 1 "Clear DTCs" function is used or 50 ignition switch keycycles have passed with no further faults or ignition switch is turned "OFF" and ECM B fuse is removed for 10 seconds.
DTC Chart Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.
1.By grounding the diagnostic terminal, the EGR solenoid should be energized and allow vacuum to be applied to the EGR valve, and the vacuum should hold.
2.The MIL should also flash while the diagnostic terminal is grounded. If the tight does not flash, this may indicate that the "quad-driver" has been damaged by low resistance in TCC circuit.
3.When the diagnostic terminal is ungrounded, the vacuum to the EGR valve should bleed off through a vent in the solenoid and the valve should close. The gage may or may not bleed off but this does not indicate a problem.
4.This test will determine if the electrical control part of the system is at fault, or if the connector or solenoid is at fault.
5.This system uses a negative backpressure valve which should hold vacuum with engine "OFF."
6.When engine is started, exhaust backpressure should cause vacuum to bleed off and valve should fully close.
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Dang lite came on......code 32 again.......I don't know? Pic of my feed.....what do I have.....+ help on the code.....
Your center key is on the bottom and the side keys are on top. Is this picture downside up?
callin my a to b......right top to left
Nope unless your picture was downside up...
Bottom Left. Note the Connector locator key positions....
You have A,B,C,G,H,J,M populated. 8192 baud ALDL. The 1994 ECM should spit out quite a lot of info over the ALDL serial link.
(http://johnnynightstick.s3.amazonaws.com/IMAGES/ALDL_plug.jpg)
[A] ECM Ground
[B) Diagnostic Enable
[C] ECM to Air Switch Solenoid
[G] Fuel Pump Prime
[H] RWAL VSS
[J] ?????
[M] 8192 Baud TTL serial data TX & RX
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Thx guy's. That is a lot of heavy knowledge, and I appreciate it. I have reread it several times. Now, if I can only get my weak mind to comprehend it all.
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Good info here
Sent from my iPhone using Tapatalk
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W/the help of Jim_Hensley, we went thru the process of elimination, our test pointed to the EGR valve itself. Ended up replacing the new EGR valve, with another new EGR valve. Go figure.. Reset the ECM. made a couple 10 mi. runs. No check lite.