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I found this online (http://www.fullsizechevy.com/showthread.php?164702-GM-Computer-Relearn-Procedure-(including-Crankshaft-relearn)&p=2208410&viewfull=1) and wanted to get some feedback on it... Please advise if this is the correct way to do a TDC Offset Relearn, Thanks!!!

DIESEL ENGINE TDC OFFSET RELEARN PROCEDURES

This procedure should only be performed when one or more of the following has occurred:

1. A diagnostic trouble code of P1214 (TDC offset not established) is present.
2. The engine has been replaced.
3. The front engine cover has been replaced.
4. The PCM with or without the injection pump has been replaced.
5. The crankshaft position sensor has been replaced.


NOTE: Replacement of only the injection pump does not require this procedure.

In order to initiate the relearn:

1. Hook up your scan tool.
2. Start the engine and idle engine until coolant temperature is at least 170 degrees F.
3. Clear any diagnostic trouble codes, if any. Then turn the engine off.
4. Turn the ignition switch to the “On” position. Do not start the engine.
5. Prepare the PCM to activate the offset relearn by placing and holding the accelerator pedal in the fully open position for no less than 45 seconds. Then release the pedal.
6. Turn the ignition switch to the “Off” position for 30 seconds. To confirm that the PCM has powered down, you should get a “No communication with vehicle” message on your scan tool.
7. Now start the engine and make sure that the coolant temperature is 170 degrees F or higher.
8. As soon as the engine coolant has reached 170 degrees F. and the engine speed is below 1500 RPM, the PCM will automatically learn the new TDC offset. A slight stumble in engine RPM is indicative that the new TDC has been activated.
9. Verify the TDC offset reading on your scan tool. The TDC offset should be between -0.25 and –0.75 degrees. If the TDC offset is within the specification, the relearn is completed. If the offset is out of specification then the injection pump must be adjusted. If the injection pump has not been replaced or adjusted and the TDC offset is very high on the positive side, then check for damage on the camshaft driven gear or key-way. If the TDC offset is very high on the negative side, check the crankshaft sensor for proper installation.
 

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Yep,Thats about the size of it.
 

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"Set base ⁠timing⁠ to 3.5 degrees with the stepper motor disabled via the TECH 2.

Then, perform a "TDC Learn" procedure and set "TDC offset"

I was told his was the only way to do it, and nothing else would work
 

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Discussion Starter #5
Okay, but what if I do not have a Tech2 scan tool... All I have is a OBDII PocketScan Code Reader. Can I still do the TDC Offset Relearn?
 

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I found this online (http://www.fullsizechevy.com/showthread.php?164702-GM-Computer-Relearn-Procedure-(including-Crankshaft-relearn)&p=2208410&viewfull=1) and wanted to get some feedback on it... Please advise if this is the correct way to do a TDC Offset Relearn, Thanks!!!

DIESEL ENGINE TDC OFFSET RELEARN PROCEDURES

This procedure should only be performed when one or more of the following has occurred:

1. A diagnostic trouble code of P1214 (TDC offset not established) is present.
2. The engine has been replaced.
3. The front engine cover has been replaced.
4. The PCM with or without the injection pump has been replaced.
5. The crankshaft position sensor has been replaced.


NOTE: Replacement of only the injection pump does not require this procedure.

In order to initiate the relearn:

1. Hook up your scan tool.
2. Start the engine and idle engine until coolant temperature is at least 170 degrees F.
3. Clear any diagnostic trouble codes, if any. Then turn the engine off.
4. Turn the ignition switch to the “On” position. Do not start the engine.
5. Prepare the PCM to activate the offset relearn by placing and holding the accelerator pedal in the fully open position for no less than 45 seconds. Then release the pedal.
6. Turn the ignition switch to the “Off” position for 30 seconds. To confirm that the PCM has powered down, you should get a “No communication with vehicle” message on your scan tool.
7. Now start the engine and make sure that the coolant temperature is 170 degrees F or higher.
8. As soon as the engine coolant has reached 170 degrees F. and the engine speed is below 1500 RPM, the PCM will automatically learn the new TDC offset. A slight stumble in engine RPM is indicative that the new TDC has been activated.
9. Verify the TDC offset reading on your scan tool. The TDC offset should be between -0.25 and –0.75 degrees. If the TDC offset is within the specification, the relearn is completed. If the offset is out of specification then the injection pump must be adjusted. If the injection pump has not been replaced or adjusted and the TDC offset is very high on the positive side, then check for damage on the camshaft driven gear or key-way. If the TDC offset is very high on the negative side, check the crankshaft sensor for proper installation.
OBD11 only?
 

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OBD 1 scan tool only. OBD2[96+] KOKO ;key on key off]
 

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Okay, but what if I do not have a Tech2 scan tool... All I have is a OBDII PocketScan Code Reader. Can I still do the TDC Offset Relearn?
Well you can do only the KOKO methode to do a relearn,but without a scan tool to verify the setting its like a blind man going target shooting.

Code readers are just reading codes.
 

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Discussion Starter #9
Well you can do only the KOKO methode to do a relearn,but without a scan tool to verify the setting its like a blind man going target shooting.

Code readers are just reading codes.

Could it hurt or better to take it somewhere for the relearn?
 

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You can try,you might get lucky if the IP was set within the perimeters.I would rather have a scan tool hooked up.
Its your call.
 

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Discussion Starter #11
In luck... I hope

My postal carrier said he has the Tech 2 tool and will bring it by to help me do the TDC offset relearn, anyone with experience using this tool that can offer some advise so that when he comes I have a clue????
 

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I am trying to do the tdc offset currently, my scanner says the offset is currently -2.5 and I have done the relearn from the PCM. I was just at the shop and set the IP timing to 3.5 on average. I need to know what I need to do to make this adjustment to -.75.
 

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I am trying to do the tdc offset currently, my scanner says the offset is currently -2.5 and I have done the relearn from the PCM. I was just at the shop and set the IP timing to 3.5 on average. I need to know what I need to do to make this adjustment to -.75.
First, what scanner are you using?

and what year vehicle?? is it an OBD1 or OBDII vehicle??
 

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Scanner is a snap on versus. Obd 2
Snap on is limited in what it can do for TDCO functions...

'96-'00 OBD2 will need the Car Code, AutoEnginuity PC software and cable or AUTEL® MaxiDAS®, available on the net, all three service GM.
All 3 are very user-friendly, does everything the TECH2 does for engine and transmission test and control. All three connect to the USB port on a laptop computer: http://www.dieselplace.com/forum/63-gm-diesel-engines/21-6-5l-diesel-engine/532050-installed-new-ip-now-tdco-2-5-after-relearn-2.html#post5275530



96 is year of truck
For information about setting timing on an OBD II : http://www.dieselplace.com/forum/63-gm-diesel-engines/21-6-5l-diesel-engine/2599-98-99-timing-setting-possibly-other-years.html

KOKO Procedure : http://www.dieselplace.com/forum/63-gm-diesel-engines/21-6-5l-diesel-engine/595794-1997-6-5-td.html#post5887642

Using Carcode to set TDCO: http://www.dieselplace.com/forum/63-gm-diesel-engines/21-6-5l-diesel-engine/764265-injection-base-timing.html#post7613962
 
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