Programming PTO Parameters - kw L18 LB7 LLY LG4 high idle UF3 program operation calibration Tech2

The following diagnosis might be helpful if the vehicle exhibits the described symptoms in the PI.

Some dealers have reported difficulty using the Tech 2 to program the operating parameters for Power Take Off -PTO applications on 2003-04 C45-85 with 8.1L / 6.6L and 7.8L engines - excluding Caterpillar Engines. CAT Engines require PTO programming using the CAT-ET system. There are two options available that require programming with the Tech 2 in order meet the customers operating requirements. The first is High Idle Option UF3 that can be programmed to provide a single high RPM idle speed. The second is Option PTO that provides multiple engine RPM selections and several operational modes for various power take off applications. These two options are exclusive to each other and cannot be ordered together on the same vehicle.

Both of these options come from the factory with generic settings and must be programmed with the Tech 2 for the specific operating parameters required by the body builder/upfitter or customer. Refer to SI Document #826997 for PTO description, operation and diagnostic information including the mode function tables and charts. Additional information is also available on the GM Engineering Upfitter Integration web site at www.gmupfitter.com under their UI Bulletin # 53. This bulletin provides an overview of High Idle and PTO operating functions, control modes, electrical schematics, part numbers and examples of the Tech 2 programming screens. Use the following procedure to reprogram the operating parameters for PTO or High Idle-UF3 with the Tech 2.

NOTE: It is important to consult with the body builder, upfitter or customer for their required RPM parameter settings for their specific vehicle application prior to programming.

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PROGRAMMING TIPS:

There must be 200 RPM difference between UF3/PTO operating RPM and base engine idle RPM. You may not be able to program parameters if any of the following conditions are present:

If the ABS / AUX / or Primary brake warning lights are on.

If the brake switch and/or tail lamps are not functioning.

If there are DTCs stored in the PCM or ECM.

If there are DTCs stored in the TCM - Allison Transmission only

If the clutch switch is not functioning - manual transmission only.

If the engine exhaust brake is activated - diesel engines only.

1. Connect and activate Tech 2 and turn ignition key on.
2. Select - Vehicle Options - and build truck in Tech 2.
3. Select - Powertrain
4. Select - Special Functions
5. Select - PTO Options
6. Select - Change Options / this screen lets the programmer verify the correct option selected
7. Select one of the following desired idle control options and follow the next step instructions:

UF3 High Idle - go to Step # 8

PTO Preset Speed Control - go to Step # 19

PTO Variable Speed Control - go to Step # 33

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UF3 HIGH IDLE PROGRAMMING:

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8. Select - FO - Fast Idle
9. Highlight - PTO Standby Speed
10. Toggle the - Decrease Button - to the desired setting below 1250 RPM. Note: 1250=MAX.
11. Highlight - PTO Engine Shutdown - and select - NO
12. Highlight - PTO Engage Relay - and select - NO
13. Highlight - PTO Feedback - and select - NO
14. Press - Reprogram
15. Turn ignition key off. Wait 30 seconds for module to power down.
16. Start engine and verify the High Idle settings with Tech 2. If not, repeat steps 10-15.
17. Depress and release the brake pedal.
18. Activate the High Idle switch and the engine speed should increase to the programmed RPM.

NOTE: When programming the Preset or Variable PTO modes, there must be a minimum of 200 RPM between the Standby, Set and Resume RPM speed parameters. Failure to do so will cause the PCM to default the engine back to base idle RPM.

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PTO PRESET SPEED CONTROL PROGRAMMING:

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19. Select - PTO Preset Speed Control
20. Select - PTO MAX Engine Speed
21. Set from 2200 to 4000 RPM as required but not below 2200 RPM
22. Select - Standby Speed - see chart in SI Doc # 826997
23. Select - PTO Set Speed - see chart in SI Doc # 826997
24. Select - PTO Resume Speed - see chart in SI Doc # 826997
25. Select - PTO MAX Engage Speed - see chart in SI Doc # 826997

NOTE: The 1000 RPM setting prevents the operator from engaging the PTO before the engine reaches operating temperature. This prevents damage to engine and other components.

26. Select - PTO Engine Shutdown - you can enable the engine shutdown system to function while operating in PTO mode or disable this function.
27. Select - PTO Engage Relay - this allows the PCM/ECM to activate the Engage Relay. Select -NO - if using a separate or remote switch to activate the PTO.
28. Select - PTO Feedback - this allows PCM/ECM to recognize PTO engagement feedback. Use only when PTO Engage Relay is selected.
29. Select - Reprogram - and verify that parameter settings are present.
30. Turn ignition key off. Wait 30 seconds for module to power down.
31. Start engine and verify the programmed settings are present with Tech 2.
32. Operate PTO and the engine speed should increase to the Standby RPM setting.

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PTO VARIABLE SPEED CONTROL PROGRAMMING:

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33. Select - PTO Variable Speed Control.
34. Select - PTO MAX Engine Speed.
35. Set from 2200 to 4000 RPM as required but not below 2200 RPM.

NOTE: 2200 RPM is recommended so that if the operator drives the truck with the PTO switch engaged, the engine will default to fuel cut off and prevent damage to the PTO.

36. Select - Standby Speed - see chart in SI DOC # 826997
37. Select - PTO MAX Engage Speed - see chart in SI Doc # 826997

NOTE: The 1000 RPM setting prevents the operator from engaging the PTO before the engine reaches operating temperature. This prevents damage to engine and other components.

38. Select - PTO Engine Shutdown - you can enable the engine shutdown system to function while operating in PTO mode or disable this function.
39. Select - PTO Engage Relay - this allows the PCM/ECM to activate the Engage Relay. Select - NO - if using a separate or remote switch to activate the PTO.
40. Select - PTO Feedback - this allows PCM/ECM to recognize PTO engagement feedback. Use only when PTO Engage Relay is selected.
41. Select - Reprogram - and verify that parameter settings are present.
42. Turn ignition key off. Wait 30 seconds for module to power down.
43. Start engine and verify the programmed settings are present with Tech 2.
44. Operate PTO and the engine speed should increase to the Standby RPM setting.

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Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

(2003-04 Chevrolet Kodiak Medium Duty Conventional C45 C55 C65 C75 C85) and ( 2003-04 GMC Topkick Medium Duty Conventional C45 C55 C65 C75 C85)

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