REVISION
This Bulletin has been revised to include 2006 LLY engine connector information. Wiring requirements for all engines are summarized in Table 1. Instructions are also provided for an alternative switch if the GM PTO switch is unavailable.
This bulletin offers an alternative method to implement Fast Idle on 2004 and beyond Full size pickups with the LLY Duramax Diesel engine.This procedure uses PTO speed control for Fast Idle.Fast Idle may be implemented as defined in UI bulletin 53 with full PTO capability but the schematic for the LLY engine is not included. A schematic for all of the engines with Fast Idle/PTO capability is included with this document.
The PTO switch must be ordered and installed separately. All wiring is present in 3600 series trucks. One wire must be added to 2500 & 3500 series trucks as described below. No tech II tool is required to implement Fast Idle with this procedure. Additional capabilities will exist if the truck is equipped with cruise control. A functional description of PTO operation is included in Bulletin #53 and the 2003 and Beyond Light Duty C/K Full Size Truck Electrical Body Builders Manual.
This procedure supercedes Bulletin #63 Fast Idle Procedure for the LB7 Engine. This Bulletin covers the following the following issues:
1. PTO Switch & mounting
2. Electrical Schematic (for additional wiring if required) 3. Connector pin-out and Location.
UI BULLETIN # 71, REV. 1
SUBJECT: LLY engine Fast Idle Procedure for2004 and beyond C/K
MODELS AFFECTED: 2004 & beyond C/K Pickups (Chevrolet & GMC)
DATE: 11/12/04
REVISION DATE: 05/19/06 PAGE: 1 of 7
ADVISORY
1. PTO Switch & Mounting PTO Accessory Kit
GM Service Parts Organization offers a PTO Accessory Kit (Part Number 12497678) that contains the PTO control switch and PTO interface wiring harness. The PTO accessory kit is required when PTO/High Idle speed control is desired but the PTO supplier kits are not utilized. The PTO accessory kit is available from your local GM dealer.
The following parts are included in the PTO Accessory Kit: • PTO control switch.
• Instruction sheet.
• PTO interface wiring harness. (Includes a mating connector to the PTO Interface Connector and approximately 3 feet of blunt cut wires)
Note: The wire supplied with the kit is not required for fast idle. PTO Control Switch
The PTO option includes a provision for a dash mounted PTO control switch. This switch is supplied with the Chelsea and Muncie
PTO kits mentioned above or it can be purchased as part of the PTO accessory kit. The PTO control switch has three positions:
• OFF • ON
• SET – (spring loaded)
Additional PTO control is available if the vehicle is equipped with Cruise Control. The Cruise Control stalk controls the following PTO functions:
• PTO SET Speed • PTO RESUME Speed
Alternative PTO Switch Replacement
The PTO Switch may not be available from GM Service Parts. Two switches may be added to simulate the function of this part.
• Latching Switch (PTO on/off)
UI BULLETIN # 71, REV. 1
(Cont.)
2. Electrical Schematic (for additional wiring if required)
Fast Idle will operate on 3600 series trucks after the switch is installed. All of the wiring required to operate Fast Idle is present. 2500 and 3500 series trucks need to have the 488 circuit added from C106 to the ECMas shown in the schematic. (See Figure1 for 2003 – 2005 engines, Figure 1a for 2006 engines.) A wiring table is offered to clarify wiring requirements for the various engines (see Table 1).
2004 – 2005 ENGINES
FIGURE 1
UI BULLETIN # 71, REV. 1
(Cont.)
2006 ENGINES
FIGURE 1a
UI BULLETIN # 71, REV. 1
(Cont.)
ECM/PCM PTO WIRING INTERFACE WIRING
Circuit # 2562 494 488 2522
Circuit Name PTO Engage PTO Engine Kill PTO Enable Switch PTO Status (Shutoff)
Wire Color PPL LT BLU LT GRN YEL
ENGINE/CONNECTOR PIN-OUT
06 LLY Diesel
C1=96 way (BLK) 31 60 8
C2=58 way (BLK) 18
04-05 LLY Diesel
C1=56 way (BLU) C2=73 way (BLK)
C3=56 way (GRY) 39 1 6 17
03-04 LB7 Diesel
C1=80 way (BLU) 71
C2=80 way (CLR) 37 56 13
8.1 L Gas
C1=80 way (BLU) 78 71 22 52
C2=80 way (GRN)
TABLE 1
UI BULLETIN # 71, REV. 1
(Cont.)
UI BULLETIN # 71, REV. 1
(Cont.)
3. Connector pin-out and Location
The Lt Green PTO ON Switch wire is located in C106 in cavity C. Pin-out and terminal information is indicated in figure 2.
C106 Engine Harness to I/P Harness (PTO)
Connector Part 15326829 Connector Part 15326833
Information 6-Way F GT 150 Series (BLK) Information 6-Way M GT 150 Series (BLK) Pin Wire Color Circuit No. Function Pin Wire Color Circuit No. Function
A YEL 2522 PTO Engage Signal A YEL 2522 PTO Engage Signal
B – – – – Not Used B – – – – Not Used
C LT GRN 488 PTO On Switch-Signal C LT GRN 488 PTO On Switch-Signal
D – – – – Not Used D – – – – Not Used
E DK BLU 84 Cruise Control Set/Coast E DK BLU 84 Cruise Control Set/Coast
Switch Signal Switch Signal
F – – – – Not Used F – – – – Not Used
3. Connector pin-out and Location (continued)
C106 is located on the side of the Underhood electrical center as indicated in figure 3.
FIGURE 3
ECM connector detail is shown in the 2003 and Beyond Light Duty C/K Full Size Truck Electrical Body Builders Manual. The Upfitter is responsible for wire selection, routing and to terminate the wires at C106 and the ECM with the appropriate connectors.
Note: Upfitter Integration website - www.gmupfitter.com
