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Engine Controls - 6.6l (Introduction) Chevrolet Cab & Chassis Silverado 3500

Testing & Diagnostics 58 illustrations ~26177 words

Temperature vs Resistance

°C°FOHMS
Temperature vs Resistance Values (Approximate)
15030247
14028460
13026677
120248100
110230132
100212177
90194241
80176332
70158467
60140667
50122973
451131188
401041459
35951802
30862238
25772796
20683520
15594450
10505670
5417280
0329420
52312300
101416180
15521450
20428680
302252700
4040100700

Temperature vs Resistance

Altitude vs Barometric Pressure

Altitude Measured in Meters (m)Altitude Measured in Feet (ft)Barometric Pressure Measured in Kilopascals (kPa)
Determine your altitude by contacting a local weather station or by using another reference source.
4 26714,00056-64
3 96213,00058-66
3 65812,00061-69
3 35311,00064-72
3 04810,00066-74
2 7439,00069-77
2 4388,00071-79
2 1347,00074-82
1 8296,00077-85
1 5245,00080-88
1 2194,00083-91
9143,00087-95
6102,00090-98
3051,00094-102
00 Sea Level96-104
3051,000101-105

Altitude vs Barometric Pressure

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Accelerator Pedal Nut20 N.m15 lb ft
Air Cleaner Housing Cover Screw4 N.m35 lb in
Air Cleaner Outlet Duct Clamp4 N.m35 lb in
Air Conditioning Compressor Bolt50 N.m37 lb ft
Air Conditioning Compressor/Power Steering Bracket Bolt46 N.m34 lb ft
Air Inlet Tube Nut10 N.m89 lb in
Air Inlet Tube to Intake Manifold Tube Bolt/Nut10 N.m89 lb in
Air Intake Pipe Clamp4.6 N.m41 lb in
Battery Positive Cable Junction Block Bracket Bolt9 N.m80 lb in
Boost Sensor Bracket Bolt9 N.m80 lb in
Camshaft Position (CMP) Sensor Bolt10 N.m89 lb in
Charged Air Cooler Duct Clamp6 N.m53 lb in
Crankshaft Position (CKP) Sensor Bolt10 N.m89 lb in
Crankshaft Position Sensor (CKP) Sensor Spacer Bolt10 N.m89 lb in
Distribution Block Fuel Line Clip Bolt25 N.m18 lb ft
Drive Belt Tensioner Bolt50 N.m37 lb ft
Electronic Brake Control Module Bracket Bolt25 N.m18 lb ft
Engine Coolant Temperature (ECT) Sensor20 N.m15 lb ft
Engine Harness Main Connector (to Bracket) Screw10 N.m89 lb in
Engine Wiring Harness Clamp Bolt10 N.m89 lb in
Engine Wiring Harness Main Connector Bracket Bolt to Engine21 N.m15 lb ft
Engine Wiring Harness Ground Bolt34 N.m25 lb ft
Exhaust Gas Recirculation (EGR) Coolant Pipe Bolt25 N.m18 lb ft
Exhaust Gas Recirculation (EGR) Cooler Tube Bolt50 N.m37 lb ft
Exhaust Gas Recirculation (EGR) Cooler Tube Rear Bolt20 N.m15 lb ft
Exhaust Gas Recirculation (EGR) Valve/Solenoid Bolt20 N.m15 lb ft
Fuel Bundle Nut16 N.m12 lb ft
Fuel Cooler Nut40 N.m30 lb ft
Fuel Feed Pipe Bolt/Nut25 N.m18 lb ft
Fuel Feed Pipe Clip Bolt10 N.m89 lb in
Fuel Feed Pipe Nut41 N.m30 lb ft
Fuel Fill Vent Hose Clamp2.5 N.m22 lb in
Fuel Filter Bracket Bolt20 N.m15 lb ft
Fuel Filter Bracket to Fuel Filter/Heater Element Housing20 N.m15 lb ft
Fuel Injection Control Module Bolt20 N.m14 lb ft
Fuel Injection Control Module Eye Bolt34 N.m25 lb ft
Fuel Injection Pump Adapter Bolt20 N.m14 lb ft
Fuel Injection Pump Bolt21 N.m15 lb ft
Fuel Injection Pump Gear Nut70 N.m52 lb ft
Fuel Injector Bracket Bolt30 N.m22 lb ft
Fuel Injector Feed Pipe Fitting41 N.m30 lb ft
Fuel Inlet Pipe to Fuel Rail Fitting41 N.m30 lb ft
Fuel Line Bracket Nut16 N.m12 lb ft
Fuel Line to Balance Pump Fitting30 N.m22 lb ft
Fuel Pipe Bracket Bolt25 N.m18 lb ft
Fuel Pressure Regulator Screws
First Pass4 N.m35 lb in
Final Pass7 N.m62 lb in
Fuel Rail Balance Pipe Bolt25 N.m18 lb ft
Fuel Rail Balance Pipe Fitting41 N.m30 lb ft
Fuel Rail Bolt25 N.m18 lb ft
Fuel Rail Pressure Sensor70 N.m52 lb ft
Fuel Tank Fill Pipe Clamp2.5 N.m22 lb in
Fuel Tank Filler Housing to Body Screw2.3 N.m20 lb in
Fuel Tank Filler Housing to Fuel Tank Fill Pipe Screw2.3 N.m20 lb in
Fuel Tank Ground Strap Bolt9 N.m80 lb in
Fuel Tank Shield Bolt18 N.m13 lb ft
Fuel Tank Strap Bolt40 N.m30 lb ft
Fuel Tank Vent Hose Clamp2.5 N.m22 lb in
Fuel Temperature Sensor22 N.m16 lb ft
Generator Bracket Bolt46 N.m34 lb ft
Generator Positive Cable Nut9 N.m80 lb in
Glow Plug18 N.m13 lb ft
Glow Plug Controller Bolt10 N.m89 lb in
Glow Plug Electrical Connector Nut2 N.m18 lb in
Glow Plug Harness Nut1.7 N.m15 lb in
Glow Plug Wiring Harness Bracket Bolt10 N.m89 lb in
Heater Outlet Hose Bolt21 N.m15 lb ft
Hood Hinge Bolts25 N.m18 lb ft
Intake Manifold Cover Clamp6 N.m53 lb in
Mass Air Flow (MAF) Sensor Screw8 N.m70 lb in
Oil Level Indicator Tube Bracket Bolt21 N.m15 lb ft
Oil Level Sensor Harness Bolt40 N.m30 lb ft
Positive Crankcase Ventilation (PCV) Pipe Bolt18 N.m13 lb ft
Power Steering Pump Bracket Rear Bolts50 N.m37 lb ft
Turbocharger Vane Position Control Solenoid Valve Bracket Bolt23 N.m17 lb ft
Turbocharger Vane Position Sensor28 N.m21 lb ft

Fastener Tightening Specifications

What Fuel to Use in the United States

In the United States, for best results use Number 2-D diesel fuel year-round, above and below freezing conditions, as oil companies blend Number 2-D fuel to address climate differences. Number 1-D diesel fuel may be used in very cold temperatures when the temperature stays below -18°C (0°F). However, the fuel will produce a power and fuel economy loss. The use of Number 1-D diesel fuel in warm or hot climates may result in stalling, poor starting when the engine is hot and may damage the fuel injection system.

Diesel fuel may foam when filling the tank. This can cause the automatic pump nozzle to shut OFF, even though the tank is not full. If this happens, just wait for the foaming to stop and then continue to fill the tank.

What Fuel to Use in Canada

Canadian fuels are blended for seasonal changes. Diesel Type A fuel is blended for better cold weather starting, when it stays below -18°C (0°F). However, the fuel will produce a power and fuel economy loss. The use of Type A diesel fuel in warmer climates may result in stalling, poor starting. Diesel Type B fuel is blended for temperatures above -18°C (0°F). The emission control system requires the use of diesel fuel with low sulfur, 0.05 percent by weight, content. Both low and higher sulfur fuels will be available in Canada. Only low sulfur diesel fuels are available in the United States. Diesel-powered trucks must be refueled only with low sulfur fuel. Use of fuels with higher-sulfur content will affect the function of the emission components and may caused reduced performance, excessive smoke and unpleasant odor.

Very Cold Weather Operation

If the vehicle is driven in very cold temperatures and can not get a winterized Number 2-D that has been adapted to cold weather or a Number 1-D, use one gallon of kerosene for every 2 gallons of diesel fuel. Once you add kerosene, run the engine for several minutes to mix the fuels. Only add kerosene when the temperature falls below -18°C (0°F), because the fuel economy and lubricating qualities of kerosene is not as good as that of diesel fuel.

In cold weather, the fuel filter may become clogged (waxed). To unclog the filter, move the vehicle to a warm garage area and warm the filter to a temperature between 0-10°C (32-50°F). Replacing the filter is not necessary.

Fuel Specific Gravity Testing

Use a J 38641-B Diesel Fuel Quality Tester to measure the fuel specific gravity (API Rating). See Special Tools . Follow the instructions on the tool to obtain the proper temerpature-adjusted value. This information must be accurate for the proper diagnosis of the fuel system.

Fuel Injector Return Flow and Fuel Pressures

The fuel return from the fuel injectors to the tank will vary based on the API value of the fuel. Measure the Fuel API with the Diesel Fuel Quality Tester. For this reason the Fuel System Diagnosis - High Pressure Side values will vary for identifying a fuel injector or fuel pump concern. Use the following tables when referred to by the diagnostic. The first table is to be used during the initial diagnosis to identify the worst fuel injectors. After the fuel injectors that fail the first part of the test are capped off, the return flow from each uncapped fuel injector must be measured again. This is because the fuel system is returning less fuel to the tank, and thus the fuel pressure is higher during the retest. Failure to use the correct table may result in the replacement of good fuel injectors.

API RatingMaximum Single Fuel Injector Return Flow
30-343 ml
35-394 ml
40-445 ml

Initial Fuel Injector Return Flow Values

API RatingMaximum Single Fuel Injector Return Flow
30-344 ml
35-395 ml
40-445 ml

Retesting Fuel Injector Return Flow Values

Water in Fuel

Sometimes, water can be pumped into the fuel tank along with diesel fuel. This can happen if the service station does not regularly inspect and clean their fuel tanks, or the fuel gets contaminated for the service stations suppliers.

If water is pumped into the fuel tank, a water in fuel light will illuminate. If the water in fuel light illuminates, the excess water must be drained from the fuel system on the vehicle.

If the vehicle is driven in very cold temperatures and can not get a winterized Number 2-D that has been adapted to cold weather or a Number 1-D, use one gallon of kerosene for every 2 gallons of diesel fuel. Once you add kerosene, run the engine for several minutes to mix the fuels. Only add kerosene when the temperature falls below -18°C (0°F), because the fuel economy and lubricating qualities of kerosene is not as good as that of diesel fuel.

In cold weather, the fuel filter may become clogged (waxed). To unclog the filter, move the vehicle to a warm garage area and warm the filter to a temperature between 0-10°C (32-50°F). Replacing the filter is not necessary.

Action Taken When the DTC Sets - Type A

The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

Action Taken When the DTC Sets - Type B

The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.

Conditions for Clearing the MIL/DTC - Type A or Type B

  1. The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
  2. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  3. Use a scan tool in order to clear the MIL and the DTC.

Non-Emissions Related DTCs

Action Taken When the DTC Sets - Type C

  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The MIL will not illuminate.
  3. The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC - Type C

  1. A last test failed, or current DTC, clears when the diagnostic runs and passes.
  2. Use a scan tool in order to clear the DTC.

Conditions for Clearing the DTC - Type X

This DTC is available in the PCM software, but has been disabled, or turned OFF. In this case, the diagnostic does not run, no DTCs are stored, and the MIL does not illuminate. Type X DTCs are used primarily for export vehicles that do not require MIL illumination or DTC storing.

Diagnostic Trouble Code (DTC) Type(s)

DTC CodeFederalCalifornia
P0016CB
P0045BB
P0046BB
P0087AA
P0088AA
P0089CA
P0090AA
P0101CB
P0102BB
P0103BB
P0112BB
P0113BB
P0116XB
P0117BB
P0118BB
P0128XB
P0168CC
P0181BB
P0182AA
P0183AA
P0192AA
P0193AA
P0201-P0208AA
P0234AA
P0237AA
P0238AA
P0299AA
P0300CB
P0301-P0308CB
P0335AA
P0336BB
P0340AA
P0341BB
P0370AA
P0374AA
P0381CB
P0401CB
P0403CB
P0404CB
P0405CB
P0406CB
P0461CC
P0462CC
P0463CC
P0500BB
P0506XB
P0507XB
P0522CC
P0523CC
P0530CC
P0562CC
P0563CC
P0567CC
P0568CC
P0571CC
P0601AA
P0602AA
P0603CC
P0604AA
P0611BB
P0612BB
P0621CC
P0622CC
P0642AA
P0643AA
P0650AA
P0652AA
P0653AA
P0670CC
P0671-P0678CC
P0698AA
P0699AA
P0700 (no mil)AA
P0802BB
P0833CC
P1093CA
P1094CC
P1125CC
P1223CB
P1226CB
P1229CB
P1232CB
P1235CB
P1238CB
P1241CB
P1244CB
P1293AA
P1294AA
P1295AA
P1296AA
P1404CB
P1550CC
P1621CC
P1626CC
P1631CC
P1637CC
P1658AA
P1687AA
P2066CC
P2067CC
P2068CC
P2122CC
P2123CC
P2128CC
P2132CC
P2133CC
P2138CC
P2139CC
P2140CC
P2146AA
P2149AA
P2227CB
P2228BB
P2229BB
P2563BB
P2564BB
P2565BB
P2610CC
P2636CC
U0073CB
U0101CB
U0105CB
U0106CB
U1300CC
U1301CC

Diagnostic Trouble Code (DTC) Type(s)

Scheme 1

Scheme 1: Fuel Injection Line Routing Diagram
Scheme 1: Fuel Injection Line Routing Diagram
CalloutComponent Name
1Fuel Rail
2Fuel Pressure Sensor
3Fuel Injectors
4Fuel Return Junction Block
5Fuel Tank
6Fuel Injection Control Module
7Fuel Filter
8First Start Fuel Bleeder Valve
9Fuel Injection Pump

Engine Controls Schematic Icons

Engine Controls Schematic Icons Icon Icon Definition NOTE: The OBD II symbol is used on the circuit diagrams in order to alert the technician that the circuit is essential for proper OBD II emission control circuit operation. Any circuit which fails and causes the malfunction indicator lamp (MIL) to turn ON, or causes emissions-related component damage, is identified as an OBD II circuit. IMPORTANT: Twisted-pair wires provide an effective shield that helps protect sensitive electronic components from electrical interference. If the wires were covered with shielding, install new shielding. In order to prevent electrical interference from degrading the performance of the connected components, you must maintain the proper specification when making any repairs to the twisted-pair wires shown : The wires must be twisted a minimum of 9 turns per 31 cm (12 in) as measured anywhere along the length of the wires The outside diameter of the twisted wires must not exceed 6.0 mm (0.25 in)

Scheme 2

Scheme 2: Engine Controls Schematic Icons
Scheme 2: Engine Controls Schematic Icons

Scheme 3

Scheme 3
Scheme 3

Scheme 4

Scheme 4: Engine Controls Schematics
Scheme 4: Engine Controls Schematics

Scheme 5

Scheme 5
Scheme 5

Scheme 6

Scheme 6
Scheme 6

Scheme 7

Scheme 7
Scheme 7

Scheme 8

Scheme 8
Scheme 8

Scheme 9

Scheme 9
Scheme 9

Scheme 10

Scheme 10
Scheme 10

Scheme 11

Scheme 11
Scheme 11

Scheme 12

Scheme 12
Scheme 12

Scheme 13

Scheme 13: Engine Controls Component Views
Scheme 13: Engine Controls Component Views
CalloutComponent Name
1Battery Tray - Left
2Engine Control Module (ECM)
3Transmission Control Module (TCM)
4Fan Shroud

Scheme 14

Scheme 14
Scheme 14
CalloutComponent Name
1Fuel Injector 7
2Glow Plug 7
3Fuel Injector 5
4Glow Plug 5
5Fuel Injector 3
6Glow Plug 3
7Fuel Injector 1
8Glow Plug 1
9Camshaft Position (CMP) Sensor
10Crankshaft Position (CKP) Sensor
11Starter
12Starter Solenoid

Scheme 15

Scheme 15
Scheme 15
CalloutComponent Name
1Glow Plug 2
2Fuel Injector 2
3Fuel Injector 4
4Glow Plug 4
5Fuel Injector 6
6Glow Plug 6
7Fuel Injector 8
8Glow Plug 8
9Engine Oil Pressure (EOP) Sensor
10Engine Oil Level Switch

Scheme 16

Scheme 16
Scheme 16
CalloutComponent Name
1Fuel Heater
2Fuel Filter
3Water In Fuel (WIF) Sensor
4Fuel Pressure Sensor
5Fuel Temperature Sensor
6Glow Plug Controller
7Baro Sensor
8Boost Pressure Sensor
9Fuel Pressure Regulator
10Fuel Injection Control Module (FICM)
11Exhaust Gas Recirculation (EGR) Valve

Scheme 17

Scheme 17
Scheme 17
CalloutComponent Name
1Engine Coolant Temperature (ECT) Sensor

Scheme 18

Scheme 18
Scheme 18
CalloutComponent Name
1Turbocharger Vane Position Control Solenoid Valve
2Turbocharger Vane Position Sensor

Scheme 19

Scheme 19
Scheme 19
CalloutComponent Name
1Fuel Pump and Sender Assembly - Primary Connector (Gas)/Fuel Level Sensor - Primary Connector (Diesel)
2Fuel Pump and Sender Assembly - Primary (Gas)/Fuel Level Sensor - Primary (Diesel)

Scheme 20

Scheme 20
Scheme 20
CalloutComponent Name
1Fuel Pump and Sender Assembly - Secondary (Gas)/Fuel Level Sensor - Secondary (Diesel)
2Fuel Pump (Diesel Only)

Scheme 21

Scheme 21
Scheme 21
CalloutComponent Name
1Auxiliary Battery Relay w/TP2
2A/C Accumulator
3A/C Low Pressure Switch
4Inner Wheel Well
5Coolant Level Switch Connector 6.6L and 8.1L
6Mass Air Flow (MAF) Sensor
7Air Cleaner Assembly
8Engine Coolant Recovery Reservoir
9Auxiliary Battery Relay Electrical Connector w/TP2

Scheme 22

Scheme 22
Scheme 22
CalloutComponent Name
1Accelerator Pedal Position (APP) Sensor Connector
2Accelerator Pedal Position (APP) Sensor

Engine Control Module (ECM) Connector End Views

Engine Control Module (ECM) - C1 Connector Part Information 15357147 56-Way F Micro 64 (BU) Pin Wire Color Circuit No. Function 1 YE 2361 SAE J1939 Serial Data Bus + 2 D-GN 2362 SAE J1939 Serial Data Bus - 3-4 - - Not Used 5 OG 440 Battery Positive Voltage 6 - - Not Used 7 OG/BK 1057 Low Reference 8 PK/BK 632 Low Reference 9 BK/WH 451 Ground 10 PK 439 Ignition 1 Voltage 11-12 - - Not Used 13 YE 492 MAF Sensor Signal 14 BN/WH 5763 EGR Valve Position Signal 15 D-GN 1049 Class 2 Serial Data 16 - - Not Used 17 TN 1274 5-Volt Reference 18 PK 1020 Ignition 0 Voltage 19 PK 439 Ignition 1 Voltage 20 OG 440 Battery Positive Voltage 21 GY 2700 5-Volt Reference 22 - - Not Used 23 OG/BK 5929 5-Volt Reference 24-25 - - Not Used 26 D-BU 507 Wait to Start Indicator Control 27 - - Not Used 28 L-BU 1162 APP Sensor 2 Signal 29 - - Not Used 30 PU/WH 1589 Fuel Level Sensor Signal - Primary 31 WH/BK 2932 5-Volt Reference 32 WH/BK 1164 5-Volt Reference 33 TN 2917 5-Volt Reference 34 GY 2705 5-Volt Reference 35 - - Not Used 36 YE/BK 1275 5-Volt Reference 37 YE 2834 Fuel Pressure Regulator Solenoid Control 39 GY 597 5-Volt Reference 40 PU/WH 2530 Fuel Pressure Regulator Solenoid Supply Voltage 41 GY 23 Generator Field Duty Cycle Signal 42 PK 1039 Ignition 1 Voltage 43 D-BU 1936 Fuel Level Sensor Signal - Secondary 44 D-GN/WH 465 Fuel Pump Relay Control 45 - - Not Used 46 YE/BK 1827 Vehicle Speed Signal 47 GY 2703 5-Volt Reference 48-49 - - Not Used 50 RD 631 12-Volt Reference 51 YE 2834 Fuel Pressure Regulator Solenoid Control 52 GY/BK 2219 FICM Relay Control 53 D-GN/WH 817 Vehicle Speed Signal 54 PU/WH 2530 Fuel Pressure Regulator Solenoid Supply Voltage 55 - - Not Used 56 PK 1039 Ignition 1 Voltage

Engine Control Module (ECM) - C2 Connector Part Information 15357131 73-Way F Micro 64 (BK) Pin Wire Color Circuit No. Function 1 - - Not Used 2 OG/BK 2919 Low Reference 3 - - Not Used 4 BN 25 Charge Indicator Control 5-6 - - Not Used 7 GY/BK 1694 4WD Low Signal 8 BK 2754 Low Reference 9-12 - - Not Used 13 BK 2751 Low Reference 14 GY 720 Low Reference 15-16 - - Not Used 17 YE/BK 508 Water in Fuel Indicator Control 18 - - Not Used 19 D-BU 1161 APP Sensor 1 Signal 20 - - Not Used 21 D-BU 2466 Trans MIL Request 22 - - Not Used 23 L-GN 432 Turbocharger Boost Sensor Signal 24 D-GN 1163 APP Sensor 3 Signal 25 TN/WH 332 Oil Pressure Sensor Signal 26 BN 1174 Oil Level Switch Signal 27 YE 1578 Fuel Temperature Signal 28 L-GN 1867 12-Volt Reference 29 GY/BK 2931 Low Reference 30 OG/BK 469 Low Reference 31 YE 5947 Turbocharger Vane Position Sensor Signal 32 - - Not Used 33 OG/BK 5764 EGR Motor High Control 34 - - Not Used 35 L-GN/ BK 5746 EGR Motor Low Control 36 BK/WH 451 Ground 37 - - Not Used 38 L-GN 1478 Coolant Level Switch Signal 39 BK 2755 Low Reference 40 BN 1271 Low Reference 41 - - Not Used 42 YE 2918 FRP Sensor Signal 43 - - Not Used 44 TN 5928 Low Reference 45 - - Not Used 46 GY/BK 433 Baro Sensor Signal 47-48 - - Not Used 49 D-BU 5930 Turbocharger Vane Position Control Solenoid Valve Control 50 WH 5931 Low Reference 51 - - Not Used 52 PK/BK 1746 Fuel Injector 3 Control 53 OG/BK 5764 EGR Motor High Control 54 PU 1272 Low Reference 55 L-GN/ BK 5746 EGR Motor Low Control 56 GY 1273 Low Reference 57 BN 2524 Generator 2 Turn on Signal 58 BK 552 Low Reference 59 - - Not Used 60 L-BU 1320 CHMSL Supply Voltage 61 PU 420 TCC Brake Switch/Cruise Control Release Signal 62 - - Not Used 63 L-BU 2832 Engine Speed Signal 64 BK 470 Low Reference 65 L-GN/BK 1745 Fuel Injector 2 Control 66 RD/BK 877 Fuel Injector 7 Control 67 YE 410 ECT Sensor Signal 68 D-BU/WH 878 Fuel Injector 8 Control 69 L-BU/BK 844 Fuel Injector 4 Control 70 BK/WH 845 Fuel Injector 5 Control 71 YE/BK 846 Fuel Injector 6 Control 72 BK 1744 Fuel Injector 1 Control 73 BK/WH 451 Ground

Scheme 23

Scheme 23: Engine Control Module (ECM) Connector End Views
Scheme 23: Engine Control Module (ECM) Connector End Views

Engine Control Module (ECM) - C3 Connector Part Information 15357148 56-Way F Micro 64 (GY) Pin Wire Color Circuit No. Function 1 L-BU 494 PTO Engine Kill Signal (PTO) 2-5 - - Not Used 6 L-GN 488 PTO on Switch Signal (PTO) 7 - - Not Used 8 BK/WH 1695 Front Axle Switch Signal 9 - - Not Used 10 PK 1039 Ignition 1 Voltage 11 - - Not Used 12 PU/WH 821 VSS High Signal (ML6) YE 400 VSS High Signal (M74) 13 - - Not Used 14 PK 1039 Ignition 1 Voltage 15-16 - - Not Used 17 YE 2522 PTO Engage Signal (PTO) 18 PU 806 Crank Voltage 19 D-BU 84 Cruise Control Set/Coast Switch Signal 20-21 - - Not Used 22 GY/BK 87 Cruise Control Resume/Accel Switch Signal 23 L-GN/BK 822 VSS Low Signal (ML6) 24 TN 472 IAT Sensor Signal 25-29 - - Not Used 30 GY 397 Cruise Control on Switch Signal 31 OG/BK 1786 Park/Neutral Signal 32 - - Not Used 33 RD/BK 380 A/C Refrigerant Pressure Sensor Signal 34 - - Not Used 35 YE/BK 625 Starter Enable Relay Control 36 - - Not Used 37 WH 121 Engine Speed Signal 38 - - Not Used 39 PU 2562 PTO Control (PTO) 40 BN/WH 419 MIL Control 41 D-GN/WH 459 A/C Compressor Clutch Relay Control 42 - - Not Used 43 YE/BK 1868 Low Reference 44 BK/WH 451 Ground 45 GY 1524 Backup Lamp Supply Voltage 46 - - Not Used 47 GY 48 CPP Switch Signal 48 BN 718 Low Reference 49-50 - - Not Used 51 BN/WH 633 CMP Sensor Signal 52 D-BU/WH 1869 CKP Sensor Signal 53-56 - - Not Used

Engine Controls Connector End Views

Accelerator Pedal Position (APP) Sensor Connector Part Information 15318071 10-Way F Metri-Pack 150 Series (GY) Pin Wire Color Circuit No. Function A GY 1273 Low Reference B PU 1272 Low Reference C L-BU 1162 APP Sensor 2 Signal D TN 1274 5-Volt Reference E BN 1271 Low Reference F D-BU 1161 APP Sensor 1 Signal G WH/BK 1164 5-Volt Reference H - - Not Used J YE/BK 1275 5-Volt Reference K D-GN 1163 APP Sensor 3 Signal

BARO Sensor Connector Part Information 12129946 3-Way F M/P 150 Series Sealed (GY) Pin Wire Color Circuit No. Function A OG/BK 1057 Low Reference B GY/BK 433 BARO Sensor Signal C WH/BK 2932 5-Volt Reference

Boost Pressure Sensor Connector Part Information 12129946 3-Way F Sealed (GY) Pin Wire Color Circuit No. Function A OG/BK 469 Low Reference B L-GN 432 Turbocharger Boost Sensor Signal C GY 597 5-Volt Reference

Camshaft Position (CMP) Sensor Connector Part Information 6248-5317 3-Way F Sealed (GY) Pin Wire Color Circuit No. Function 1 BN/WH 633 CMP Sensor Signal 2 PK/BK 632 Low Reference 3 RD 631 5-Volt Reference

Crankshaft Position (CKP) Sensor Connector Part Information 6248-5317 3-Way F Sealed (GY) Pin Wire Color Circuit No. Function 1 D-BU/WH 1869 CKP Sensor Signal 2 YE/BK 1868 Low Reference 3 L-GN 1867 12-Volt Reference

Engine Coolant Temperature (ECT) Sensor Connector Part Information 12162192 2-Way Metri-Pack 150.2 Series, Sealed, Pull To Seat (BK) Pin Wire Color Circuit No. Function A GY 720 Low Reference B YE 410 ECT Sensor Signal

Exhaust Gas Recirculation (EGR) Valve Connector Part Information 6195-0021 6-Way F DL Series Sealed (GY) Pin Wire Color Circuit No. Function A PU 2703 5-Volt Reference B YE/BK 2754 Low Reference C D-BU/WH 5763 EGR Valve Position Signal D PK 5764 EGR Motor High Control E - - Not Used F WH 5746 EGR Motor Low Control

Fuel Heater Connector Part Information 7118-3320-30 2-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 PK 239 Ignition 1 Voltage 2 BK 50 Ground

Fuel Injection Control Module (FICM) Connector - C1 Connector Part Information 1928403454 81-Way F Bosch Series (BK) Pin Wire Color Circuit No. Function 1 WH/L-GN IC18 Fuel Injector 4 Command 2 YE/BK IZ17 Ground 3 OG IC13 Injector Supply Voltage 4 RD/L-GN IC15 Fuel Injector 1 Command 5 PK 339 Ignition 1 Voltage 6-43 - - Not Used 44 L-BU/BK 844 Fuel Injector 4 Control 45 BK/WH 845 Fuel Injector 5 Control 46 - - Not Used 47 PK/BK 1746 Fuel Injector 3 Control 48 RD/BK 877 Fuel Injector 7 Control 49-58 - - Not Used 59 D-BU/WH IC20 Fuel Injector 6 Command 60 D-BU/WH IC520 Fuel Injector 6 Command 61 WH/RD IC21 Fuel Injector 7 Command 62 WH/RD IC521 Fuel Injector 7 Command 63 D-BU/WH 878 Fuel Injector 8 Control 64 YE/BK 846 Fuel Injector 6 Control 65 - - Not Used 66 BK 1744 Fuel Injector 1 Control 67 L-GN/BK 1745 Fuel Injector 2 Control 68-81 - - Not Used

Fuel Injection Control Module (FICM) Connector - C2 Connector Part Information 1928403462 40-Way F Bosch Series (BK) Pin Wire Color Circuit No. Function 82-89 - - Not Used 90 D-GN 2362 SAE J1939 Serial Data Bus - 91 YE 2361 SAE J1939 Serial Data Bus + 92-93 - - Not Used 94 L-BU 2832 Engine Speed Signal 95-113 - - Not Used 114 BK/GN IZ18 Ground 115 WH/L-BU IC17 Fuel Injector 3 Command 116 RD/L-GN IC19 Fuel Injector 5 Command 117 - - Not Used 118 RD/WH IC60 Injector Supply Voltage 119 PK 339 Ignition 1 Voltage 120 WH/GN IC22 Fuel Injector 8 Command 121 WH/YE IC16 Fuel Injector 2 Command

Scheme 24

Scheme 24: Engine Controls Connector End Views
Scheme 24: Engine Controls Connector End Views

Fuel Injector 1 Connector Part Information 1928403874 2-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 RD/L-GN IC15 Fuel Injector 1 Command 2 OG IC13 Injector Supply Voltage

Fuel Injector 2 Connector Part Information 1928403874 2-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 WH/YE IC16 Fuel Injector 2 Command 2 RD/WH IC14 Injector Supply Voltage

Fuel Injector 3 Connector Part Information 1928403874 2-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 WH/BU IC17 Fuel Injector 3 Command 2 RD/WH IC60 Injector Supply Voltage

Fuel Injector 4 Connector Part Information 1928403874 2-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 WH/L-GN IC18 Fuel Injector 4 Command 2 OG IC62 Injector Supply Voltage

Fuel Injector 5 Connector Part Information 1928403874 2-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 RD/L-GN IC19 Fuel Injector 5 Command 2 RD/WH IC61 Injector Supply Voltage

Fuel Injector 6 Connector Part Information 1928403874 2-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 D-BU/WH IC20 Fuel Injector 6 Command 2 OG IC64 Injector Supply Voltage

Fuel Injector 7 Connector Part Information 1928403874 2-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 WH/RD IC21 Fuel Injector 7 Command 2 OG IC63 Injector Supply Voltage

Fuel Injector 8 Connector Part Information 1928403874 2-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 WH/GN IC22 Fuel Injector 8 Command 2 RD/WH IC65 Injector Supply Voltage

Fuel Level Sensor - Primary Connector Part Information 12160563 2-Way F Metri-Pack 150 Series Sealed (NA) Pin Wire Color Circuit No. Function A PU 1589 Fuel Level Sensor Signal - Primary B - C - - Unavailable D OG/BK 510 Low Reference

Fuel Level Sensor - Secondary w/Dual Tanks Connector Part Information 12160563 2-Way F Metri-Pack 150 Series Sealed (NA) Pin Wire Color Circuit No. Function A D-BU 1936 Fuel Level Sensor Signal - Secondary B - C - - Unavailable D OG/BK 510 Low Reference

Fuel Pressure Regulator Connector Part Information 12059450 3-Way M Sealed (BK) Pin Wire Color Circuit No. Function 1 PU/WH 2530 Fuel Pressure Regulator Solenoid Supply Voltage 2 YE 2834 Fuel Pressure Solenoid Control 3 BK - Shield

Fuel Rail Pressure (FRP) Sensor Connector Part Information 1928403968 3-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 OG/BK 2919 Low Reference 2 YE 2918 FRP Sensor Signal 3 TN 2917 5-Volt Reference

Fuel Pump w/Dual Tanks Connector Part Information 12059450 2-Way M Metri-Pack 280 Series Sealed (BK) Pin Wire Color Circuit No. Function A GY 120 Fuel Pump Supply Voltage B BK 1650 Ground (20 Series) BK 2150 Ground (30 Series)

Fuel Temperature Sensor Connector Part Information 178392-6 2-Way F Sealed (GY) Pin Wire Color Circuit No. Function 1 YE 1578 Fuel Temperature Signal 2 BN 718 Low Reference

Glow Plug Controller - C1 Connector Part Information 15443870 1-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 BK 1042 Battery Positive Voltage

Glow Plug Controller - C2 Connector Part Information 60412601 E 12-Way F Sealed (BK) Pin Wire Color Circuit No. Function 1 RD/GN HB11 Glow Plug 1 Supply Voltage 2 WH/GN HB12 Glow Plug 2 Supply Voltage 3 RD/WH HB13 Glow Plug 3 Supply Voltage 4 WH/YE HB14 Glow Plug 4 Supply Voltage 5 PK 239 Ignition 1 Voltage 6 D-GN 2362 SAE J1939 Serial Data Bus 7 RD/L-GN HB15 Glow Plug 5 Supply Voltage 8 WH/L-GN HB16 Glow Plug 6 Supply Voltage 9 RD/BU HB17 Glow Plug 7 Supply Voltage 10 WH/BU HB18 Glow Plug 8 Supply Voltage 11 PK/YE HB03 Ground 12 YE 2361 SAE J1939 Serial Data Bus +

Intake Air Temperature (IAT)/Mass Air Flow (MAF) Sensor Connector Part Information 15324447 5-Way F 090II SLD (BK) Pin Wire Color Circuit No. Function 1 BK 552 Low Reference 2 TN 472 IAT Sensor Signal 3 PK 439 Ignition 1 Voltage 4 GY/BK 2931 Low Reference 5 YE 492 MAF Sensor Signal

Turbocharger Vane Position Control Solenoid Valve Connector Part Information PR-IA066070097 2-Way F Sealed (BK) Pin Wire Color Circuit No. Function A D-BU 5930 Turbocharger Vane Position Control Solenoid Valve B WH 5931 Low Reference

Turbocharger Vane Position Sensor Connector Part Information 282088-1 4-Way F Superseal 1.5 Series Sealed (BK) Pin Wire Color Circuit No. Function A OG/BK 5929 5-Volt Reference B TN 5928 Low Reference C YE 5775 Turbocharger Vane Position Sensor Signal D - - Not Used

Scheme 25

Scheme 25
Scheme 25

Engine Control Module (ECM) Replacement

Service of the engine control module (ECM) should consist of either replacement of the ECM or programming of the electrically erasable programmable read only memory (EEPROM). If the diagnostic procedures call for the ECM to be replaced, the replacement ECM should be checked to ensure that the correct part is being used. If the correct part is being used, remove the faulty ECM and install the new service ECM.

Removal Procedure

IMPORTANTTo prevent internal ECM damage, the ignition switch must be OFF when disconnecting or connecting power to the ECM. Remove any debris from the ECM connector surfaces before servicing the ECM. Inspect the ECM module connector gaskets when diagnosing or replacing the ECM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the ECM. The replacement ECM must programmed.
  1. Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.
  2. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  3. Disconnect the ECM electrical connectors (2).
  4. Release the ECM cover retaining tabs.
  5. Remove the ECM cover from the bracket.
  6. Remove the ECM cover.

Installation Procedure

  1. Install the ECM.
  2. Install the ECM cover to the bracket.
  3. Engage the ECM cover retaining tabs.
  4. Connect the ECM electrical connectors (2).
  5. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  6. If a NEW ECM was installed, program the ECM. Refer to «Control Module References»(ref-197326-S18267990112005101100000) in Computer/Integrating Systems.
  7. Perform the turbocharger learn procedure. Refer to «Turbocharger Learn Procedure»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Remove the fuel fill cap in order to relieve the fuel pressure.
  3. Cut the tie strap attaching the harness to the bracket.
  4. Disconnect the fuel injection control module (FICM) electrical connectors. Pull the retainers out until the connectors disengage.
  5. Remove and discard the fuel line eye bolts.
  6. Remove and discard the fuel line eye bolt washers from the banjo fittings.
  7. Remove the FICM bolts.
  8. Remove the FICM with insulators.
  9. If necessary, remove the oil level indicator tube bracket bolt from the FICM bracket.
  10. If necessary, remove the fuel line and engine harness clips from the FICM bracket.
  11. If necessary, remove the FICM bracket bolts.
  12. If necessary, remove the FICM bracket.
  1. If necessary, install the FICM bracket.
  2. If necessary, install the FICM bracket bolts.
  3. If necessary, install the fuel line and engine harness clips to the FICM bracket.
  4. If necessary, install the oil level indicator tube bracket bolt to the FICM bracket. Tighten: Tighten the bolt to 21 N.m (15 lb ft).
  5. Install the FICM with insulators.
  6. Install the FICM bolts. Tighten: Tighten the bolt to 20 N.m (14 lb ft).
  7. Lubricate the NEW eye bolt washers with diesel fuel prior to installing.
  8. Install the NEW eye bolt washers to the banjo fittings.
  9. Install the NEW fuel line eye bolts. Tighten: Tighten the bolt to 34 N.m (25 lb ft).
  10. Connect the FICM electrical connectors. Slide the retainers in to engage the connectors.
  11. Install a NEW tie strap attaching the harness to the bracket.
  12. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  13. Install the fuel fill cap.
  14. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  15. Start the engine. If the engine stalls, repeat the above step.
  16. Once the engine starts, inspect for fuel leaks.
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Remove the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  3. Remove both front wheelhouse panels. Refer to «Wheelhouse Panel Replacement»(ref-197355-S26734560152005101100000) in Body Front End.
  4. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Loosen the charged air cooler outlet duct to intake hose clamp. IMPORTANT: Do not use a screwdriver or other tool to pry the hose loose. The hose can be torn or damaged. Loosen the hose by twisting.
  6. Remove the charged air cooler outlet duct from the intake.
  7. Loosen the charged air cooler inlet duct connector to turbocharger clamp (1).
  8. Remove the charged air cooler inlet duct connector (4) from the turbocharger.
  9. Disconnect the fuel injection control module electrical connectors.
  10. Cut the tie strap attaching the harness to the bracket.
  11. Remove the left glow plug harness bracket bolts.
  12. Remove the right glow plug harness bracket bolts.
  13. Remove the positive crankcase ventilation (PCV) hose/pipe. Refer to «Crankcase Ventilation Hoses/Pipes Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  14. Disconnect the engine coolant temperature (ECT) sensor electrical connector.
  15. Disconnect the exhaust gas recirculation (EGR) valve electrical connector.
  16. Disconnect the camshaft position (CMP) sensor electrical connector.
  17. Remove the 2 ground bolts.
  18. Disconnect the crankshaft position (CKP) sensor electrical connector.
  19. Remove the tie strap from the electrical harness.
  20. Disconnect the main engine electrical harness connectors. Lift up on the latches (1) in order to disconnect the connectors.
  21. Open the harness clip (2).
  22. Remove the main engine electrical harness connectors.
  23. Disconnect the barometric sensor electrical connector.
  24. Remove the main engine electrical harness connector bolts.
  25. Disconnect the fuel pressure control valve electrical connector.
  26. Disconnect the turbocharger boost sensor electrical connector.
  27. Disconnect the oil level sensor electrical harness connector.
  28. Disconnect the fuel temperature sensor electrical connector.
  29. Disconnect the glow plug controller electrical connector.
  30. Disconnect the glow plug controller battery feed electrical connector (1).
  31. Disconnect and remove the turbocharger vane position sensor.
  32. Disconnect the fuel injector electrical connectors.
  33. Disconnect the turbocharger vane control solenoid valve.
  34. Disconnect the fuel rail pressure sensor electrical connector.
  35. Disconnect the oil pressure sensor electrical connector.
  36. Remove the oil level sensor harness bolt.
  37. Remove the glow plug controller bolts.
  38. Remove the glow plug controller.
  39. Remove the glow plug electrical connector nuts.
  40. Remove the engine wiring harness.
  1. Install the engine wiring harness.
  2. Install the glow plug electrical connector nuts. Tighten: Tighten the nuts to 2 N.m (18 lb in).
  3. Install the glow plug controller.
  4. Install the glow plug controller bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
  5. Install the oil level sensor harness bolt. Tighten: Tighten the bolt to 40 N.m (30 lb ft).
  6. Connect the oil pressure sensor electrical connector.
  7. Connect the fuel rail pressure sensor electrical connector.
  8. Connect the turbocharger vane control solenoid valve.
  9. Connect the fuel injector electrical connectors.
  10. Install and connect the turbocharger vane position sensor.
  11. Connect the glow plug controller battery feed electrical connector (1).
  12. Connect the glow plug controller electrical connector.
  13. Connect the fuel temperature sensor electrical connector.
  14. Connect the oil level sensor electrical harness connector.
  15. Connect the turbocharger boost sensor electrical connector.
  16. Connect the fuel pressure control valve electrical connector.
  17. Install the main engine electrical harness connector screws. Tighten: Tighten the screws to 10 N.m (89 lb in).
  18. Connect the barometric sensor electrical connector.
  19. Connect the main engine electrical harness connectors.
  20. Push down on the latches (1) in order to connect the connectors.
  21. Close the harness clip (2).
  22. Install a NEW tie strap to the electrical harness.
  23. Connect the CKP sensor electrical connector.
  24. Install the 2 ground bolts. Tighten: Tighten the bolts to 34 N.m (25 lb ft).
  25. Connect the CMP sensor electrical connector.
  26. Connect the EGR valve electrical connector.
  27. Connect the ECT sensor electrical connector.
  28. Install the PCV hose/pipe. Refer to «Crankcase Ventilation Hoses/Pipes Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  29. Install the right glow plug harness bracket bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
  30. Install the right glow plug connectors to the glow plugs. Tighten: Tighten the glow plug connector nuts to 2 N.m (18 lb in).
  31. Install the left glow plug harness bracket bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in.
  32. Install the left glow plug connectors to the glow plugs. Tighten: Tighten the glow plug connector nuts to 2 N.m (18 lb in).
  33. Connect the fuel injection control module electrical connectors.
  34. Install a NEW tie strap attaching the harness to the bracket.
  35. Remove the tape from the turbocharger openings.
  36. Install the charged air cooler inlet duct connector (4) to the turbocharger.
  37. Tighten the charged air cooler inlet duct connector to turbocharger clamp (1). Tighten: Tighten the clamp to 6 N.m (53 lb in).
  38. Install the charged air cooler outlet duct to the intake.
  39. Tighten the charged air cooler outlet duct to intake hose clamp. Tighten: Tighten the clamp to 6 N.m (53 lb in).
  40. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  41. Install both front wheelhouse panels. Refer to «Wheelhouse Panel Replacement»(ref-197355-S26734560152005101100000) in Body Front End.
  42. Install the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  43. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.

Note. Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

  1. Drain the coolant to a level below the engine coolant temperature (ECT) sensor. Refer to «Draining and Filling Cooling System (w/RPO HP2)»(ref-197356-S32653343972005101100000) or «Draining and Filling Cooling System (w/o RPO HP2)»(ref-197356-S16321664992005101100000) in Engine Cooling.
  2. Disconnect the ECT sensor electrical connector.
  3. Remove the ECT sensor (1).

Note. Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

  1. If installing the old sensor, coat the threads with sealant GM P/N 12346004 (Canadian P/N 10953480), or equivalent.
  2. Install the ECT sensor (1). Tighten: Tighten the sensor to 20 N.m (15 lb ft).
  3. Connect the ECT sensor electrical connector.
  4. Fill the cooling system, if necessary. Refer to «Draining and Filling Cooling System (w/RPO HP2)»(ref-197356-S32653343972005101100000) or «Draining and Filling Cooling System (w/o RPO HP2)»(ref-197356-S16321664992005101100000) in Engine Cooling.
  1. Disconnect the mass air flow (MAF)/intake air temperature (IAT) sensor electrical connector (1).
  2. Remove the MAF/IAT sensor TORX® screws.
  3. Remove the MAF/IAT sensor (1).
  1. Install the MAF/IAT sensor (1).
  2. Install the MAF/IAT sensor TORX® screws. Tighten: Tighten the screws to 8 N.m (70 lb in).
  3. Connect the MAF/IAT sensor electrical connector (1).
  1. Disconnect the barometric pressure (BARO) sensor electrical connector.
  2. Push the BARO sensor (1) downward in order to remove it from the bracket.
  1. Push the BARO sensor (1) upward in order to remove it from the bracket.
  2. Connect the BARO sensor electrical connector.
  1. Remove the right fuel rail fuel feed pipe. Refer to «Fuel Rail Fuel Feed Pipe Replacement - Right»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Remove the boost sensor bracket bolt (1).
  3. Remove the boost sensor and bracket.
  4. Separate the boost sensor from the bracket.
  5. Inspect the sensor seal for damage, replace as necessary.
  1. Position the boost sensor onto the bracket.
  2. Install the boost sensor and bracket.
  3. Install the boost sensor bracket bolt (1). Tighten: Tighten the bolt to 9 N.m (80 lb in).
  4. Install the right fuel rail fuel feed pipe. Refer to «Fuel Rail Fuel Feed Pipe Replacement - Right»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .

Note. Handle the electronic throttle control components carefully. Use cleanliness in order to prevent damage. Do not drop the electronic throttle control components. Do not roughly handle the electronic throttle control components. Do not immerse the electronic throttle control components in cleaning solvents of any type.

  1. Remove the connector position assurance (CPA) retainer.
  2. Disconnect the accelerator pedal position (APP) sensor electrical connector.
  3. Reposition the carpet to access the lower nut.
  4. Remove the accelerator pedal nuts.
  5. Remove the accelerator pedal assembly.
  1. Install the accelerator pedal assembly.
  2. Install the accelerator pedal nuts. Tighten: Tighten the nuts to 20 N.m (15 lb ft).
  3. Connect the APP sensor electrical connector.
  4. Reposition the carpet.
  5. Install the CPA retainer.
  6. Connect a scan tool in order to test for proper throttle-opening and throttle-closing range.
  7. Operate the accelerator pedal and monitor the throttle angles. The accelerator pedal should operate freely, without binding, between a closed throttle and a wide open throttle (WOT).
  8. Verify that the vehicle meets the following conditions: The vehicle is not in a reduced engine power mode. The ignition is ON. The engine is OFF.
  9. Inspect the carpet fit under the accelerator pedal.

Quick Connect Fitting(s) Service (Metal Collar)

Tools Required

  1. J 44581 Fuel Line Disconnect Tool. See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__special-tools) .
  2. J 43178 Fuel Line Disconnect Tool
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Remove the fuel fill cap.
  3. Remove the retainers from the fuel feed and return pipe quick connect fittings.
  4. Using compressed air, blow any dirt or debris from around the fitting.
  5. Using the correct end of J 44581 for the size of the fitting. See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__special-tools) . Insert J 44581 into the female connector, then push inward in order to release the locking tabs. See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__special-tools) .
  6. If the vehicle is a cab/chassis, it may be necessary to use J 43178 in order to release the quick connect fittings at the sending unit.
  7. Pull the connection apart.
  8. Use a clean shop towel in order to wipe off the male end. NOTE: If necessary, remove rust or burrs from the fuel pipes with an emery cloth. Use a radial motion with the fuel pipe end in order to prevent damage to the O-ring sealing surface. Use a clean shop towel in order to wipe off the male tube ends. Inspect all the connections for dirt and burrs. Clean or replace the components and assemblies as required.
  9. Inspect both ends of the fitting for dirt and burrs. Clean or replace the components as required.
CAUTIONIn order to reduce the risk of fire and personal injury, before connecting fuel pipe fittings, always apply a few drops of clean engine oil to the male pipe ends. This will ensure proper reconnection and prevent a possible fuel leak. During normal operation, the O-rings located in the female connector will swell and may prevent proper reconnection if not lubricated.
  1. Apply a few drops of clean engine oil to the male connection end.
  2. Push both sides of the fittings together in order to snap the retaining tabs into place.
  3. Once installed, pull on both sides of the connections in order to make sure the connection is secure.
  4. Install the retainers to the fuel feed/return pipes.
  5. Install the fuel fill cap.
  6. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
IMPORTANTThere are several types of plastic fuel and evaporative emission (EVAP) quick connect fittings used on this vehicle. The following instructions apply to all types of plastic quick connect fittings except where indicated.
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Remove fuel fill cap.
  3. Using compressed air, blow any dirt from around the quick connect fitting.
  4. Squeeze the plastic quick connect fitting release tabs together to disengage the quick connect fitting. (This step applies to Bartholomew style fittings ONLY).
  5. Squeeze where indicated by the arrows on both sides of the plastic ring to disengage the quick connect fitting.
  6. Squeeze where indicated by the arrows on both sides of the plastic ring to disengage the quick connect fitting.
  7. Pull the connection apart.
  1. Apply a few drops of clean engine oil to the male connection end.
  2. Push both sides of the quick connect fitting together in order to cause the retaining tabs to snap into place.
  3. Once installed, pull on both sides of the quick connect fitting in order to make sure the connection is secure.
  4. Install the fuel fill cap.
  5. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.

Fuel System Priming

IMPORTANTIn order for the DURAMAX diesel fuel system to work properly, the fuel lines must be full of fuel and contain no air. If air gets into the fuel lines, it will be necessary to prime the fuel system to eliminate the air before operating the vehicle. Air could have entered the system in one of the following ways: The vehicle ran out of fuel. The filter was removed for service or replacement. The fuel lines were removed or disconnected for servicing. The fuel filter water drain cock was opened while the engine was running. If one or more of the above occurred, air has entered the fuel system and you will need to prime the system prior to operating the vehicle.
  1. Prior to priming the engine, ensure that the following has been completed: There is fuel in the fuel tank. The fuel filter has been installed and properly tightened. The fuel lines are properly connected. The fuel filter is cool to the touch. Any dirt or debris has been removed from the fuel filter head and vent valve.
  2. Open the vent valve by turning the screw counterclockwise several full turns.
  3. Operate the priming pump until a small amount of fuel seeps from the vent valve. Allow the pump to return upward between pumps. When fuel is present, the filter is full of fuel and the system should be primed.
  4. Close the vent valve.
  5. Clean any fuel which accumulated on the fuel filter.
  6. Start the engine and allow it to idle for a few minutes.
  7. Check the filter for leaks.
  1. Drain the fuel from the fuel filter. Refer to «Water-in-Fuel Draining Procedure»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__water-in-fuel-draining-procedure) .
  2. Reposition the fuel hose clamps.
  3. Remove the fuel hoses.
  4. Disconnect the fuel filter connectors.
  5. Unscrew the fuel filter from the fuel filter adapter.
  6. Remove the water-in-fuel sensor from the fuel filter.
  1. Install the water-in-fuel sensor to the NEW fuel filter.
  2. Screw on the NEW fuel filter to the fuel filter adapter.
  3. Connect the fuel filter connectors.
  4. Install the fuel hoses.
  5. Position the fuel hose clamps.
  6. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  7. Start the engine. If the engine stalls, repeat the above step.
  8. Once the engine starts, inspect for fuel leaks.

Fuel Filter Life Reset

This message will appear when a reset is performed either by using the steering wheel controls or following manual procedure.

  1. Reset the fuel filter monitor.
  2. For vehicles with steering wheel controls, press and hold the select button for 5 seconds while the FUEL FILTER LIFE message is displayed. This message will appear on the driver information center (DIC) for ten seconds.
  3. For vehicles without steering wheel controls, do the following: Without pressing the pedals, turn the ignition key to the ON position without starting the engine. Wait 5 seconds. Completely press the brake and the accelerator pedals simultaneously and hold for 10 seconds. The system is now reset. Turn the ignition key OFF.
  4. The next time the engine is started, the message will no longer be displayed. ALWAYS reset the FUEL FILTER LIFE system after a fuel filter change.
  1. Drain the fuel from the fuel filter. Refer to «Water-in-Fuel Draining Procedure»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__water-in-fuel-draining-procedure) .
  2. Remove the right front wheelhouse panel. Refer to «Wheelhouse Panel Replacement»(ref-197355-S26734560152005101100000) in Body Front End.
  3. Disconnect the fuel filter electrical connectors.
  4. Remove the water-in-fuel sensor (3) from the fuel filter (2).
  1. Install the water-in-fuel sensor (3) to the fuel filter (2).
  2. Connect the fuel filter electrical connector.
  3. Install the right front wheelhouse panel. Refer to «Wheelhouse Panel Replacement»(ref-197355-S26734560152005101100000) in Body Front End.
  4. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  5. Start the engine. If the engine stalls, repeat the above step.
  6. Once the engine starts, inspect for fuel leaks.

Water-in-Fuel Draining Procedure

  1. Attach a small piece of hose to the drain cock onto the water-in-fuel sensor.
  2. Place an approved fuel-resistant container under the fuel filter.
  3. Open the drain cock 3 or 4 turns or until the water contaminated fuel seeps from the drain cock.
  4. Operate the priming pump until only diesel fuel is visible. Allow the pump to return upward between pushes.
  5. Tighten the drain cock.
  6. Remove the container and hose.
  1. Drain the fuel from the fuel filter. Refer to «Water-in-Fuel Draining Procedure»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__water-in-fuel-draining-procedure) .
  2. Reposition the fuel hose clamps.
  3. Remove the fuel hoses.
  4. Disconnect the fuel filter electrical connectors.
  5. Remove the fuel filter bracket bolts.
  6. Remove the fuel filter assembly.
  7. Remove the fuel filter bracket bolts and bracket from the fuel filter/heater element housing.
  8. Remove the fuel filter from the fuel filter/heater element housing.
  9. Inspect the fuel filter, replace if necessary.
  1. Install the fuel filter to the fuel filter/heater element housing.
  2. Install the fuel filter bracket and bolts to the fuel filter/heater element housing. Tighten: Tighten the bolts to 20 N.m (15 lb ft).
  3. Install the fuel filter assembly.
  4. Install the fuel filter bracket bolts. Tighten: Tighten the bolts to 20 N.m (15 lb ft).
  5. Connect the fuel filter electrical connectors.
  6. Install the fuel hoses.
  7. Position the fuel hose clamps.
  8. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  9. Start the engine. If the engine stalls, repeat the above step.
  10. Once the engine starts, inspect for fuel leaks.

Tools Required

J 45004 Fuel Tank Siphon Hose

IMPORTANTPurge any residual fuel in J 45004 into an approved container prior to use.
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Remove the fuel fill cap.
  3. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-197364-S02039416942005101100000) in General Information.
  4. Loosen the fuel fill pipe clamp (2).
  5. Remove the fuel fill pipe from the fuel tank.
  6. Insert the J 45004 hose into the tank.
  7. Attach the J 45004 hose to the hose used with the hand or air operated pump devise.
  8. Using a hand or air operated pump drain as much fuel from the tank as possible.
  1. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Remove the fuel tank filler housing to body screws (1), and retainer (2).
  3. Remove the fuel tank filler housing to fuel tank fill pipe screws.
  4. Remove the fuel tank filler housing.
  5. Remove the rear axle vent hose from the clip on the fuel fill pipe bracket.
  6. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-197364-S02039416942005101100000) in General Information.
  7. Remove the fuel tank ground strap bolt (1).
  8. Reposition the fuel tank ground strap (3).
  9. Loosen the fill pipe vent hose clamp (1) at the fuel tank.
  10. Remove the fill pipe vent hose from the fuel tank.
  11. Remove the fill pipe.
  12. Remove the fuel system cooler. Refer to «Fuel System Cooler Replacement (Pickup)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel System Cooler Replacement (Cab/Chassis)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  13. If equipped, remove the fuel tank shield bolts.
  14. If equipped, remove the fuel tank shield.
  15. Disconnect the fuel feed and return lines. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  16. Cap the fuel lines in order to prevent possible fuel system contamination.
  17. Place a suitable adjustable jack under the fuel tank.
  18. Remove the fuel tank strap bolts.
  19. Remove the fuel tank straps.
  20. Lower the fuel tank until the sending unit electrical connector is accessible.
  21. Disconnect the sending unit electrical connector.
  22. Completely lower the fuel tank.
  23. With the aid of an assistant, place the fuel tank in a suitable work area.
  24. If necessary, disconnect and remove the fuel feed (1) and return (2) lines from the sending unit and retaining clips. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  25. If replacing the fuel tank, remove the sending unit. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  1. If the fuel tank was replaced, install the sending unit. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Install and connect the fuel feed (1) and return (2) lines to the sending unit and retaining clips. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  3. With the aid of an assistant, place the fuel tank on the jack.
  4. Raise the fuel tank until the sending unit electrical connection can be made.
  5. Connect the sending unit electrical connector.
  6. Install the fuel tank.
  7. Install the fuel tank straps. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  8. Install the fuel tank strap bolts. Tighten: Tighten the bolts to 40 N.m (30 lb ft).
  9. Remove the jack from under the fuel tank.
  10. Remove the caps from the fuel lines.
  11. Connect the fuel feed and return lines to the fuel tank. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  12. If necessary, install the fuel tank shield.
  13. If necessary, install the fuel tank shield bolts. Tighten: Tighten the bolts to 18 N.m (13 lb ft).
  14. Install the fuel system cooler. Refer to «Fuel System Cooler Replacement (Pickup)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel System Cooler Replacement (Cab/Chassis)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  15. Install the fuel tank fill pipe and vent hose to the fuel tank.
  16. Tighten the fuel tank fill pipe clamp (2) at the fuel tank. Tighten: Tighten the clamp to 2.5 N.m (22 lb in).
  17. Tighten the fuel tank vent hose clamp (1) at the fuel tank. Tighten: Tighten the clamp to 2.5 N.m (22 lb in).
  18. Position the fuel tank ground strap (3).
  19. Install the fuel tank ground strap bolt (1). Tighten: Tighten the bolt to 9 N.m (80 lb in).
  20. Install the rear axle vent hose to the clip on the fuel fill pipe bracket.
  21. Lower the vehicle.
  22. Install the fuel tank filler housing.
  23. Install the fuel tank filler housing to fuel tank fill pipe screws. Tighten: Tighten the screws to 2.3 N.m (20 lb in).
  24. Install the fuel tank filler housing to body screws (1), and retainer (2). Tighten: Tighten the screws to 2.3 N.m (20 lb in).
  25. Fill the fuel tank.
  26. Install the fuel fill cap.
  27. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  28. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  29. Start the engine. If the engine stalls, repeat the above step.
  30. Once the engine starts, inspect for fuel leaks.
  1. Disconnect the fuel feed and pressure balance rear lines. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  2. Loosen the fuel fill and vent hose clamps (1, 2) at the fuel tank.
  3. Remove the fuel fill pipe and vent hose from the tank.
  4. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Disconnect the sending unit electrical connectors (1).
  6. Disconnect the fuel feed and return lines from the fuel tank. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  7. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-197364-S02039416942005101100000) in General Information.
  8. If necessary, remove the fuel tank shield bolts.
  9. If necessary, remove the fuel tank shield.
  10. Place a suitable adjustable jack under the fuel tank.
  11. Remove the fuel tank strap bolts.
  12. Remove the fuel tank straps.
  13. Lower the fuel tank.
  14. With the aid of an assistant, place the fuel tank in a suitable work area.
  15. Cap the fuel lines on the vehicle in order to prevent possible fuel system contamination.
  16. If replacing the fuel tank, remove the sending unit. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  1. If the fuel tank was replaced, install the sending unit. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Remove the caps from the fuel lines.
  3. With the aid of an assistant, place the fuel tank on the jack.
  4. Raise the fuel tank.
  5. Install the fuel tank straps. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  6. Install the fuel tank strap bolts. Tighten: Tighten the bolts to 40 N.m (30 lb ft).
  7. Remove the jack from under the fuel tank.
  8. If necessary, install the fuel tank shield.
  9. If necessary, install the fuel tank shield bolts. Tighten: Tighten the bolts to 18 N.m (13 lb ft).
  10. Lower the vehicle.
  11. Connect the fuel feed and return lines at the fuel tank. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  12. Connect the sending unit electrical connectors (1).
  13. Install the fuel fill pipe and vent hose to the tank.
  14. Tighten the fuel fill and vent hose clamps (1, 2) at the fuel tank. Tighten: Tighten the clamps to 2.5 N.m (22 lb in).
  15. Connect the fuel feed and pressure balance rear lines. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  16. Fill the fuel tank.
  17. Install the fuel fill cap.
  18. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  19. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  20. Start the engine. If the engine stalls, repeat the above step.
  21. Once the engine starts, inspect for fuel leaks.
  1. Loosen the fuel fill and vent hose clamps (1, 2) at the tank.
  2. Remove the fuel fill and vent hose from the tank.
  3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  4. Disconnect the sending unit electrical connector.
  5. Disconnect the fuel feed and return lines from the sending unit. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  6. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-197364-S02039416942005101100000) in General Information.
  7. If equipped, remove the fuel tank shield bolts.
  8. If equipped, remove the fuel tank shield.
  9. Remove the fuel tank strap bolts.
  10. Remove the fuel tank straps.
  11. Lower the fuel tank.
  12. With the aid of an assistant, place the fuel tank in a suitable work area.
  13. Cap the fuel lines in order to prevent possible fuel system contamination.
  14. If replacing the fuel tank, remove the sending unit. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  1. If the fuel tank was replaced, install the sending unit. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Remove the caps from the fuel lines.
  3. With the aid of an assistant, place the fuel tank on the jack.
  4. Raise the fuel tank.
  5. Install the fuel tank straps. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  6. Install the fuel tank strap bolts. Tighten: Tighten the bolts to 40 N.m (30 lb ft).
  7. Remove the jack from under the fuel tank.
  8. If equipped, install the fuel tank cover.
  9. If equipped, install the fuel tank cover bolts. Tighten: Tighten the bolts to 18 N.m (13 lb ft).
  10. Lower the vehicle.
  11. Connect the fuel feed and return lines to the sending unit. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  12. Connect the sending unit electrical connector.
  13. Install the fuel fill and vent hose to the tank.
  14. Tighten the fuel fill and vent hose clamps (1, 2) at the tank. Tighten: Tighten the hose clamps to 2.5 N.m (22 lb in).
  15. Fill the fuel tank.
  16. Install the fuel fill cap.
  17. Install the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  18. Using a scan tool, command the fuel transfer pump on.
  19. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  20. Start the engine. If the engine stalls, repeat the above step.
  21. Once the engine starts, inspect for fuel leaks.
  1. Remove the sending unit. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Disconnect the fuel level sensor electrical connector (1).
  3. Remove the sensor retaining clip (3).
  4. Squeeze the locking tangs (2) and remove the fuel level sensor.
  1. Install the fuel level sensor.
  2. Install the sensor retaining clip (3).
  3. Connect the sensor electrical connector (1).
  4. Install the sending unit. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  1. Loosen the fuel fill cap to relieve the fuel system pressure.
  2. Disconnect the balance pump electrical connector.
  3. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-197364-S02039416942005101100000) in General Information.
  4. Clean the fuel line connections and surrounding areas at the pump before disconnecting to avoid possible fuel system contamination.
  5. Disconnect the fuel lines from the pump.
  6. Slide the pump out of the bracket.
  7. Cap the fuel lines.
  1. Remove the caps from the fuel lines.
  2. Install the NEW fuel line O-rings.
  3. Position the new balance pump into the bracket.
  4. Connect the fuel lines to the balance pump. Use a backup wrench to prevent the pump from turning. Tighten: Tighten the fittings to 30 N.m (22 lb ft).
  5. Lower the vehicle.
  6. Connect the balance pump electrical connector.
  7. Tighten the fuel fill cap.
  8. Using a scan tool, command the fuel transfer pump on.
  9. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  10. Start the engine. If the engine stalls, repeat the above step.
  11. Once the engine starts, inspect for fuel leaks.

J 45722 Fuel Sender Lock Ring Wrench

  1. Remove the fuel tank. Refer to «Fuel Tank Replacement (Pickup)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel Tank Replacement (Cab/Chassis - Front)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel Tank Replacement (Cab/Chassis - Rear)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Disconnect the fuel lines from the sending unit. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) or «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  3. Using J 45722 , remove the sending unit lock ring.
  4. Remove the sending unit and seal. Discard the seal.
  5. Clean the sending unit sealing surfaces.
  1. Install the sending unit and a NEW seal.
  2. Using J 45722 , install the sending unit lock ring.
  3. Connect the fuel lines to the sending unit. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) or «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  4. Install the fuel tank. Refer to «Fuel Tank Replacement (Pickup)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel Tank Replacement (Cab/Chassis - Front)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel Tank Replacement (Cab/Chassis - Rear)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  1. Reposition the hose clamps at the fuel filter and the return line.
  2. Remove the fuel hose (1) from the fuel filter housing and the return line.
  1. Install the fuel hose (1) to the fuel filter housing and return line.
  2. Position the hose clamps at the fuel filter and the return line.
  3. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  4. Start the engine. If the engine stalls, repeat the above step.
  5. Once the engine starts, inspect for fuel leaks.
  1. Remove the water outlet. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  2. Remove the air intake tube. Refer to «Air Intake Pipe Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  3. Reposition the fuel hose clamps (1) at the return/feed line as required.
  4. Disconnect the fuel hoses from the return/feed line as required.
  5. Reposition the fuel hose clamps (1) at the injection pump as required.
  6. Disconnect the fuel hoses (2, 3) from the injection pump as required.
  7. Remove the fuel hoses from the vehicle as required.
  1. Install the fuel hoses to the vehicle as required.
  2. Connect the fuel hoses (2, 3) to the injection pump as required.
  3. Position the fuel hose clamps (1) at the injection pump as required.
  4. Connect the fuel hoses to the return/feed line as required.
  5. Position the fuel hose clamps (1) at the return/feed line as required.
  6. Install the air intake tube. Refer to «Air Intake Pipe Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  7. Install the water outlet. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  8. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  9. Start the engine. If the engine stalls, repeat the above step.
  10. Once the engine starts, inspect for fuel leaks.
  1. Remove the water outlet. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  2. Remove the air intake tube. Refer to «Air Intake Pipe Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  3. Reposition the fuel hose clamps (1) at the return/feed line as required.
  4. Disconnect the fuel hoses from the return/feed line as required.
  5. Reposition the fuel hose clamps (1) at the injection pump as required.
  6. Disconnect the fuel hoses (2, 3) from the injection pump as required.
  7. Remove the fuel hoses from the vehicle as required.
  1. Install the fuel hoses to the vehicle as required.
  2. Connect the fuel hoses (2, 3) to the injection pump as required.
  3. Position the fuel hose clamps (1) at the injection pump as required.
  4. Connect the fuel hoses to the return/feed line as required.
  5. Position the fuel hose clamps (1) at the return/feed line as required.
  6. Install the air intake tube. Refer to «Air Intake Pipe Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  7. Install the water outlet. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  8. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  9. Start the engine. If the engine stalls, repeat the above step.
  10. Once the engine starts, inspect for fuel leaks.
  1. Disconnect the fuel feed and return lines. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  2. Remove the fuel line bracket nut.
  3. Remove the fuel line bracket from the stud.
  4. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-197364-S02039416942005101100000) in General Information.
  5. Remove the fuel bundle clips (2) from the transmission brackets (1).
  6. Disconnect the chassis harness from the retaining clips.
  7. Remove the fuel system cooler, if necessary. Refer to «Fuel System Cooler Replacement (Pickup)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel System Cooler Replacement (Cab/Chassis)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  8. Disconnect the fuel feed and return lines from the fuel tank lines. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  9. Remove the fuel bundle nuts from the chassis.
  10. Loosen the electronic brake control module (EBCM) bracket bolts (4).
  11. Allow the EBCM to remain loose in order to allow fuel pipe clearance.
  12. Remove the fuel bundle using the following procedure: Guide the fuel bundle pipes towards the rear of the vehicle to clear the engine. Lower the fuel bundle while moving it forward and out.
  1. Install the fuel pipe bundle using the following procedure: Install the fuel bundle to the chassis by guiding the pipes towards the rear of vehicle. Lift the fuel pipes, while guiding the forward portion of the pipes up towards the engine connections. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  2. Install the fuel bundle nuts to the chassis. Tighten: Tighten the nuts to 16 N.m (12 lb ft).
  3. Connect the fuel feed and return lines to the fuel tank lines. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  4. Install the fuel system cooler, if necessary. Refer to «Fuel System Cooler Replacement (Pickup)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel System Cooler Replacement (Cab/Chassis)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Connect the fuel bundle clips (2) to the transmission brackets (1).
  6. Tighten the EBCM bracket bolts (4). Tighten: Tighten the bolts to 25 N.m (18 lb ft).
  7. Lower the vehicle.
  8. Install the fuel line bracket to the stud.
  9. Install the fuel line bracket nut. Tighten: Tighten the nut to 16 N.m (12 lb ft).
  10. Connect the fuel feed and return lines. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  11. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  12. Start the engine. If the engine stalls, repeat the above step.
  13. Once the engine starts, inspect for fuel leaks.
  1. Disconnect the fuel feed and return lines. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  2. Remove the fuel line bracket nut.
  3. Remove the fuel line bracket from the stud.
  4. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-197364-S02039416942005101100000) in General Information.
  5. Remove the fuel bundle clips (2) from the transmission brackets (1).
  6. Disconnect the chassis harness from the retaining clips.
  7. Remove the fuel system cooler, if necessary. Refer to «Fuel System Cooler Replacement (Pickup)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel System Cooler Replacement (Cab/Chassis)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  8. Disconnect the fuel feed and return lines from the fuel tank lines. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  9. Remove the fuel bundle nuts from the chassis.
  10. Loosen the electronic brake control module (EBCM) bracket bolts (4).
  11. Allow the EBCM to remain loose in order to allow fuel pipe clearance.
  12. Remove the fuel bundle using the following procedure: Guide the fuel bundle pipes towards the rear of vehicle to clear the engine. Lower the fuel bundle while moving it foreword and out.
  1. Install the fuel pipe bundle using the following procedure: Install the fuel bundle to the chassis by guiding the pipes towards the rear of vehicle. Lift the fuel pipes, while guiding the forward portion of the pipes up towards the engine connections. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  2. Install the fuel bundle nuts to the chassis. Tighten: Tighten the nuts to 16 N.m (12 lb ft).
  3. Connect the fuel feed and return lines to the fuel tank lines. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  4. Install the fuel system cooler, if necessary. Refer to «Fuel System Cooler Replacement (Pickup)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel System Cooler Replacement (Cab/Chassis)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Connect the fuel bundle clips (2) to the transmission brackets (1).
  6. Tighten the EBCM bracket bolts (4). Tighten: Tighten the bolts to 25 N.m (18 lb ft).
  7. Lower the vehicle.
  8. Install the fuel line bracket to the stud.
  9. Install the fuel line bracket nut. Tighten: Tighten the nut to 16 N.m (12 lb ft).
  10. Connect the fuel feed and return lines. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  11. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  12. Start the engine. If the engine stalls, repeat the above step.
  13. Once the engine starts, inspect for fuel leaks.
  1. Remove the front and auxiliary fuel tanks. Refer to «Fuel Tank Replacement (Pickup)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel Tank Replacement (Cab/Chassis - Front)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel Tank Replacement (Cab/Chassis - Rear)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Disconnect the pressure balance pump electrical connector.
  3. Remove the fuel bundle nuts.
  4. Remove the fuel bundle.
  1. Install the fuel bundle.
  2. Install the fuel bundle nuts. Tighten: Tighten the nuts to 16 N.m (12 lb ft).
  3. Connect the pressure balance pump electrical connector.
  4. Install the front and auxiliary fuel tanks. Refer to «Fuel Tank Replacement (Pickup)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel Tank Replacement (Cab/Chassis - Front)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) or «Fuel Tank Replacement (Cab/Chassis - Rear)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  1. Remove the glow plug controller. Refer to «Glow Plug Controller Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Disconnect the return line from the return/junction block line.
  3. Remove the fuel return line clips.
  4. Remove the fuel injector return line from the injectors.
  1. Install the fuel injector return line to the injectors.
  2. Install the fuel return line clips.
  3. Connect the return line to the return/junction block line.
  4. Install the glow plug controller. Refer to «Glow Plug Controller Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  6. Start the engine. If the engine stalls, repeat the above step.
  7. Once the engine starts, inspect for fuel leaks.
  1. Remove the fuel injection control module (FICM). Refer to «Fuel Injection Control Module Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Remove the fuel filter and bracket. Refer to «Fuel Filter Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  3. Disconnect the return line from the return/junction block line.
  4. Remove the fuel return line clips.
  5. Remove the fuel injector return line from the injectors.
  1. Install the fuel injector return line to the injectors.
  2. Install the fuel return line clips.
  3. Connect the return line to the return/junction block line.
  4. Install the fuel filter and bracket. Refer to «Fuel Filter Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Install the FICM. Refer to «Fuel Injection Control Module Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  6. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  7. Start the engine. If the engine stalls, repeat the above step.
  8. Once the engine starts, inspect for fuel leaks.
  1. Remove the water outlet tube. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  2. Disconnect the fuel feed line quick connect fitting. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  3. Remove the fuel injection control module upper banjo bolt and washer.
  4. Reposition the exhaust gas recirculation (EGR) coolant pipe hose clamp.
  5. Remove the EGR coolant pipe hose.
  6. Remove the EGR coolant pipe bolts.
  7. Remove the EGR coolant pipe.
  8. Remove the fuel feed pipe nut and clip bolts.
  9. Remove the fuel feed pipe.
  1. Install the fuel feed pipe.
  2. Install the fuel feed pipe nut and clip bolts. Tighten: Tighten the bolts/nut to 41 N.m (30 lb ft).
  3. Install the EGR coolant pipe.
  4. Install the EGR coolant pipe bolts. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
  5. Install the EGR coolant pipe hose.
  6. Position the EGR coolant pipe hose clamp.
  7. Lubricate a NEW washer with diesel fuel.
  8. Install the fuel injection control module upper banjo bolt and the NEW washer. Tighten: Tighten the bolt to 34 N.m (25 lb ft).
  9. Connect the fuel feed line quick connect fitting. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  10. Install the water outlet tube. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  11. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  12. Start the engine. If the engine stalls, repeat the above step.
  13. Once the engine starts, inspect for fuel leaks.
  1. Remove the engine wiring harness. Refer to «Engine Wiring Harness Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Remove the water outlet. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  3. Remove the exhaust gas recirculation (EGR) cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  4. Reposition the fuel return line hose clamps (1).
  5. Remove the fuel return line hoses from the return line.
  6. Remove the fuel return line clamp bolts (1).
  7. Reposition the fuel return line hose clamp (3) from the fuel rail.
  8. Remove the fuel return line hose from the fuel rail.
  9. Remove the fuel return line (2).
  1. Install the fuel return line (2).
  2. Install the fuel return line hose to the fuel rail.
  3. Position the fuel return line hose clamp (3) at the fuel rail. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  4. Install the fuel return line clamp bolts (1). Tighten: Tighten the bolts to 25 N.m (18 lb ft).
  5. Install the fuel return line hoses to the return line.
  6. Position the fuel return line hose clamps (1).
  7. Install the EGR cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  8. Install the water outlet. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  9. Install the engine wiring harness. Refer to «Engine Wiring Harness Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  10. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  11. Start the engine. If the engine stalls, repeat the above step.
  12. Once the engine starts, inspect for fuel leaks.
  1. Remove the engine wiring harness. Refer to «Engine Wiring Harness Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Remove the water outlet. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  3. Remove the exhaust gas recirculation (EGR) cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  4. Disconnect the right fuel rail feed pipe fittings (1, 3).
  5. Remove the fuel rail pipe clamp bolts (2).
  6. Remove the right fuel rail feed pipe.
  1. Install the right fuel rail feed pipe.
  2. Install the fuel rail pipe clamp bolts (2). Tighten: Tighten the bolts to 25 N.m (18 lb ft).
  3. Connect the right fuel rail feed pipe fittings (1, 3). Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  4. Install the EGR cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Install the water outlet. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  6. Install the engine wiring harness. Refer to «Engine Wiring Harness Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  7. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  8. Start the engine. If the engine stalls, repeat the above step.
  9. Once the engine starts, inspect for fuel leaks.
  1. Remove the water outlet. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  2. Reposition the return line hose clamps at the return line and injection pump.
  3. Remove the hose (3) from the return line and injection pump.
  4. Disconnect the left fuel rail feed pipe fittings (1).
  5. Remove the left fuel rail feed pipe.
  1. Install the left fuel rail feed pipe.
  2. Connect the left fuel rail feed pipe fittings (1). Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  3. Install the hose (3) to the return line and injection pump.
  4. Position the return line hose clamps at the return line and injection pump.
  5. Install the water outlet. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  6. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  7. Start the engine. If the engine stalls, repeat the above step.
  8. Once the engine starts, inspect for fuel leaks.
  1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Loosen the charged air cooler outlet duct to intake hose clamp. IMPORTANT: Do not use a screwdriver or other tool to pry the hose loose. The hose can be torn or damaged. Loosen the hose by twisting.
  3. Remove the charged air cooler outlet duct from the intake.
  4. Remove the fuel filter. Refer to «Fuel Filter Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Remove the fuel rail pressure sensor. Refer to «Fuel Rail Pressure (FRP) Sensor Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  6. Prior to removing the fuel injector pipes, use compressed air to blow any debris from between the injector line and fittings. Wipe the fittings clean of debris.
  7. Spray lithium grease, GM P/N 12346293 or equivalent, between the fuel injector line and fittings to assist in containing any debris during removal.
  8. Remove the fuel injector pipes.

Note. Ensure proper torquing of the fuel injector line. An under-torqued fuel injector line will not seal properly and an over-torqued fuel injector line may damage the fuel injector fitting. An improperly sealed or damaged fuel injector line or fuel injector fitting will cause a fuel leak.

  1. Install the fuel injector pipes. Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  2. After installing the fuel injector pipes, clean the injector pipes and apply sealant GM P/N 97720043, at the fittings to prevent moisture and debris from collecting between the line and fitting.
  3. Install the fuel rail pressure sensor. Refer to «Fuel Rail Pressure (FRP) Sensor Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  4. Install the fuel filter. Refer to «Fuel Filter Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Installer the charged air cooler outlet duct to the intake.
  6. Tighten the charged air cooler outlet duct to intake hose clamp. Tighten: Tighten the clamp to 6 N.m (53 lb in).
  7. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  8. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  9. Start the engine. If the engine stalls, repeat the above step.
  10. Once the engine starts, inspect for fuel leaks.
  1. Remove the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  2. Drain the cooling system. Refer to «Draining and Filling Cooling System (w/RPO HP2)»(ref-197356-S32653343972005101100000) or «Draining and Filling Cooling System (w/o RPO HP2)»(ref-197356-S16321664992005101100000) in Engine Cooling.
  3. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  4. Loosen the charged air cooler inlet duct connector to turbocharger clamp (1).
  5. Remove the charged air cooler inlet duct connector (4) from the turbocharger.
  6. Remove the battery cable to generator nut.
  7. If equipped, remove the battery cable to auxiliary generator nut.
  8. Remove the battery cable harness clip from the bracket.
  9. Remove the battery cable junction block bolt (1) from the power steering pump.
  10. Move and secure the battery cables out of the way.
  11. Disconnect the fuel lines. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  12. Remove the fuel line bracket nut.
  13. Remove the fuel line bracket from the stud.
  14. Disconnect the main engine electrical harness connectors. Lift up on the latches (1) in order to disconnect the connectors.
  15. Open the harness clip (2).
  16. Remove the main engine electrical harness connectors.
  17. Remove the engine harness main electrical connectors bolts.
  18. Disconnect the barometric sensor electrical connector.
  19. Remove the engine harness main connector bracket bolts.
  20. Remove the water outlet tube. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  21. Remove the auxiliary generator, if equipped. Refer to «Generator Replacement - Auxiliary (6.6L (LLY) Engine)»(ref-197347-S33514212702005101100000) in Engine Electrical.
  22. Disconnect the glow plug controller electrical connector.
  23. Disconnect the glow plug controller battery feed electrical connector (1).
  24. Remove the positive crankcase ventilation (PCV) hose/pipe. Refer to «Crankcase Ventilation Hoses/Pipes Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  25. Prior to removing the fuel injector pipes, use compressed air to blow any debris from between the injector line and fittings. Wipe the fittings clean of debris.
  26. Spray lithium grease, GM P/N 12346293 or equivalent, between the fuel injector line and fittings to assist in containing any debris during removal.
  27. Remove the left fuel injector pipes.

Note. Ensure proper torquing of the fuel injector line. An under-torqued fuel injector line will not seal properly and an over-torqued fuel injector line may damage the fuel injector fitting. An improperly sealed or damaged fuel injector line or fuel injector fitting will cause a fuel leak.

  1. Install the fuel injector pipes. Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  2. After installing the fuel injector pipes, clean the injector pipes and apply sealant GM P/N 97720043, at the fittings to prevent moisture and debris from collecting between the line and fitting.
  3. Install the PCV hose/pipe. Refer to «Crankcase Ventilation Hoses/Pipes Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  4. Connect the glow plug controller battery feed electrical connector (1).
  5. Connect the glow plug controller electrical connectors.
  6. Install the auxiliary generator, if equipped. Refer to «Generator Replacement - Auxiliary (6.6L (LLY) Engine)»(ref-197347-S33514212702005101100000) in Engine Electrical.
  7. Install the water outlet tube. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  8. Install the engine harness main connector bracket bolts. Tighten: Tighten the bolts to 21 N.m (15 lb ft).
  9. Connect the barometric sensor electrical connector.
  10. Install the engine harness main electrical connectors bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
  11. Connect the main engine electrical harness connectors.
  12. Push down on the latches (1) in order to connect the connectors.
  13. Close the harness clip (2).
  14. Install the fuel line bracket from the stud.
  15. Install the fuel line bracket nut. Tighten: Tighten the nut to 21 N.m (15 lb ft).
  16. Connect the fuel lines. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  17. Position the generator positive cable.
  18. Install the generator positive cable in the clip on the engine front cover.
  19. Install the generator positive cable and nut to the generator. Tighten: Tighten the nut to 9 N.m (80 lb in).
  20. Install the battery positive cable junction block bracket and bolt (1) to the power steering bracket. Tighten: Tighten the bolt to 9 N.m (80 lb in).
  21. Remove the tape from the turbocharger openings.
  22. Install the charged air cooler inlet duct connector (4) to the turbocharger.
  23. Tighten the charged air cooler inlet duct connector to turbocharger clamp (1). Tighten: Tighten the clamp to 6 N.m (53 lb in).
  24. Install the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  25. Fill the cooling system. Refer to «Draining and Filling Cooling System (w/RPO HP2)»(ref-197356-S32653343972005101100000) or «Draining and Filling Cooling System (w/o RPO HP2)»(ref-197356-S16321664992005101100000) in Engine Cooling.
  26. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  27. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  28. Start the engine. If the engine stalls, repeat the above step.
  29. Once the engine starts, inspect for fuel leaks.
  1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-197364-S02039416942005101100000) in General Information.
  2. Disconnect the fuel lines at the cooler (1). Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  3. Remove the fuel cooler bolts (4, 6).
  4. Remove the fuel cooler (1).
  5. Remove the fuel cooler support bracket bolt (2, 5), and bracket (3) from the fuel cooler (1), if necessary.
  1. Install the fuel cooler support bracket (3), and bolts (2, 5) to the fuel cooler (1), if necessary. Tighten: Tighten the bolts to 18 N.m (13 lb ft).
  2. Install the fuel cooler (1) to the chassis and crossover.
  3. Install the fuel cooler bolts (4, 6). Tighten: Tighten the bolts to 18 N.m (13 lb ft).
  4. Connect the fuel lines at the fuel cooler (1). Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  5. Lower the vehicle.
  6. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  7. Start the engine. If the engine stalls, repeat the above step.
  8. Once the engine starts, inspect for fuel leaks.
  1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-197364-S02039416942005101100000) in General Information.
  2. Disconnect the fuel lines at the fuel cooler (1). Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  3. Remove the fuel cooler nuts (2).
  4. Remove the fuel cooler (1).
  1. Install the fuel cooler (1).
  2. Install the fuel cooler nuts (2). Tighten: Tighten the nuts to 40 N.m (30 lb ft).
  3. Connect the fuel lines at the fuel cooler (1). Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  4. Lower the vehicle.
  5. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  6. Start the engine. If the engine stalls, repeat the above step.
  7. Once the engine starts, inspect for fuel leaks.
  1. Remove the fuel tank filler housing to body screws (1) and retainer (2).
  2. Remove the fuel tank filler pipe housing to fuel tank fill pipe screws.
  3. Remove the fuel tank filler housing.
  4. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-197364-S02039416942005101100000) in General Information.
  5. Remove the fuel tank ground strap bolt (1).
  6. Remove the chassis harness ground strap (2) and fuel tank ground strap (3).
  7. Remove the rear axle vent hose from the clip on the fuel fill pipe bracket.
  8. Loosen the fuel tank vent hose and fill hose clamps (1, 2).
  9. Remove the vent hose from the tank.
  10. Remove the fill hose from the tank and the vehicle.
  11. Cap the opening on the fuel tank in order to prevent possible fuel system contamination.
  1. Remove the cap from the opening on the fuel tank.
  2. Install the fill hose to the vehicle and tank.
  3. Install the vent hose to the tank. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  4. Tighten the fuel tank vent hose and fill hose clamps (1, 2). Tighten: Tighten the clamp to 2.5 N.m (22 lb in).
  5. Install the rear axle vent hose to the clip on the fuel fill pipe bracket.
  6. Position the chassis harness ground strap (2) and fuel tank ground strap (3).
  7. Install the ground strap anti-rotation tab into the frame hole.
  8. Install the fuel tank ground strap bolt (1). Tighten: Tighten the bolt to 9 N.m (80 lb in).
  9. Lower the vehicle.
  10. Install the fuel tank filler housing.
  11. Install the fuel tank filler housing to fuel tank fill pipe screws. Tighten: Tighten the screws to 2.3 N.m (20 lb in).
  12. Install the fuel tank filler housing to body screws (1) and retainer (2). Tighten: Tighten the screws to 2.3 N.m (20 lb in).
  1. Relieve the fuel system pressure.
  2. Disconnect the fuel feed and pressure balance rear lines. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  3. Loosen the fuel fill and vent hose clamps (1, 2) at the tank.
  4. Remove the fuel fill and vent hoses from the tank.
  5. Cap the fuel and vent holes in the fuel tank in order to prevent possible fuel system contamination.
  1. Remove the caps from the fuel and vent holes in the fuel tank.
  2. Install the fuel fill and vent hoses to the tank. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  3. Tighten the fuel fill and vent hose clamps (1, 2) at the tank. Tighten: Tighten the clamp to 2.5 N.m (22 lb in).
  4. Connect the fuel feed and pressure balance rear lines. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .

Fuel System Cleaning

Fungi and other microorganisms can survive and multiply in diesel fuel if water is present. The fungi can be present in any part of the fuel handling system. These fungi grow into long strings and will form into large globules. The growths appear slimy and are usually black, green, or brown. The fungi may grow anywhere in the fuel but are most plentiful where diesel fuel and water meet. As the fuel is agitated, when service station tanks are being filled, fungi are distributed throughout the tank and may be pumped into a vehicle.

Fungi use the fuel as their main energy supply and need only trace amounts of water and minerals. As they grow and multiply, they change fuel into water, sludge, acids, and products of metabolism. The most common symptom is fuel filter plugging; however, various metal components including the fuel sending unit, pipes, fuel injectors, and injection pump can corrode.

CAUTIONAvoid physical contact with the biocides in order to avoid personal injury.

If fungi have caused fuel system contamination, use a diesel fuel biocide to sterilize the fuel system. Do not exceed the dosage recommended on the label. Discontinue the use of a biocide when towing a trailer. It is permissible to have biocide in the fuel when starting to tow, but do not add any biocide while towing.

Steam cleaning may be necessary if most of the fungus growth cannot be removed with biocides.

The presence of water or gasoline in diesel fuel may also cause injection pump and nozzle damage.

This procedure checks for the presence of water and gasoline in diesel fuel that may cause injection pump and nozzle damage.

Remove and inspect the fuel filter element.

  1. If water, gasoline or fungi/bacteria are not present, end the inspection.
  2. If water or fungi/bacteria are present, proceed to Cleaning Water from the Fuel System.
  3. If gasoline is present, proceed to Cleaning Gasoline from the Fuel System.

Cleaning Water from the Fuel System

  1. Disconnect the negative battery. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Remove the sending unit. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  3. Inspect the fuel tank and the fuel sender for rust, fungi or bacteria. If there is rust, replace the rusted components.
  4. Clean the inside of the fuel tank and the fuel sender with hot water.
  5. Use compressed air in order to dry the fuel tank and the fuel sender.
  6. Disconnect the ends of the following lines: The fuel filter inlet line (both ends) The transfer pump pressure line and suction line (if applicable) The fuel filter outlet line (both ends) The fuel filter drain The fuel return line (both ends)
  7. Inspect each of the pipes and lines.
  8. Replace any rusted pipes.
  9. Clean the inside of the fuel filter housing.
  10. Dry the fuel filter housing with compressed air.
  11. Dry the inside of each line with low pressure air.
  12. Remove the ignition 1 relay from the underhood relay center.
  13. Install a new fuel filter. Refer to «Fuel Filter Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  14. Install the sending unit Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  15. Add clean diesel fuel to the primary tank until the tank is 1/4 full.
  16. Reconnect the following lines: The fuel filter inlet line The fuel filter outlet line The transfer pump pressure and suction (both ends) lines The fuel return line (tank end)
  17. Connect the fuel filter drain to a line that flows into a clean metal container.
  18. Connect the batteries.
  19. Operate the fuel system hand primer at the fuel filter until clean fuel flows from the fuel filter drain into a metal container.
  20. Close the fuel filter drain and remove the bleeder hose.
  21. Install a hose on the fuel return line near the glow plug relay, and insert other end into a 7.6 liters (2 gallon) metal container.
  22. Crank the engine for 30 second time intervals, with 1 minute cool-down periods. Continue until 3.8 liters (1 gallon) of fuel has passed into the container.
  23. Connect the fuel return line.
  24. Install the ignition 1 relay in the underhood relay center.
  25. Start and run the engine.
  26. Stop the engine.
  27. Clean any fuel spillage from the engine.
  28. Fill the fuel tank and add a biocide, if needed.

Cleaning Gasoline from the Fuel System

  1. Drain the fuel tank.
  2. Fill the fuel tank to 1/4 full.
  3. Remove the ignition 1 relay from the underhood relay center.
  4. Loosen the fuel filter drain and connect the filter to a hose that flows into a metal container.
  5. Operate the fuel system hand primer at the fuel filter until clean fuel flows from the fuel filter drain into the metal container.
  6. Hand tighten the fuel filter drain and disconnect the hose.
  7. Install a hose on the fuel return line near the glow plug relay, and insert the other end into a 7.6 liters (2 gallon) metal container.
  8. Crank the engine for 30 second time intervals, with 1 minute cool-down periods. Continue until 3.8 liters (1 gallon) of fuel has passed into the container.
  9. Reconnect the fuel return line.
  10. Install the ignition 1 relay into the underhood relay center.
  11. Attempt to start and run the engine for 15 minutes. If the engine does not start, operate the hand primer for 30 strokes, or until firm.
  12. Stop the engine.
  13. Clean any fuel spillage from the engine.
  14. Clear the engine of any diagnostic trouble codes (DTCs).

Fuel Feed and Fuel Return Pipe Purge Procedure

  1. Pump the primer located on top of the fuel filter 30 times or until stiff.
  2. Attempt to start and run the engine. If the engine does not start, repeat step 1.
  3. Allow to run for 5 minutes at idle.
  4. Check for fuel leaks.
  5. Clear all engine diagnostic trouble codes (DTCs).
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Remove the water outlet tube. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  3. Remove the battery cable junction block bracket bolt (1) from the power steering pump bracket.
  4. Reposition the junction block and bracket.
  5. Loosen the charged air cooler inlet duct to turbocharger clamp (1).
  6. Remove the charged air cooler inlet duct connector (4) from the turbocharger.
  7. Disconnect the fuel feed and return line quick connect fittings. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  8. Remove the fuel line bracket nut.
  9. Remove the fuel line bracket from the stud.
  10. Remove the positive crankcase ventilation (PCV) hose/pipe. Refer to «Crankcase Ventilation Hoses/Pipes Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  11. Remove the air conditioning (A/C) compressor bolts.
  12. Reposition the A/C compressor aside.
  13. Remove the banjo bolt and washer from the fuel injection control module.
  14. Remove the fuel feed pipe nuts/bolts.
  15. Remove the fuel feed pipe.
  16. Disconnect the fuel rail balance pipe from the fuel rails.
  17. Remove the fuel rail balance pipe bolts.
  18. Remove the fuel rail balance pipe.
  19. Disconnect the fuel injector return hose from the return/junction block line.
  20. Reposition the return/junction block hose clamps at the injection pump.
  21. Remove the fuel hoses from the return/junction block.
  22. Reposition the return/junction block hose clamp at the rear of the left fuel rail.
  23. Remove the fuel hose from the fuel rail.
  24. Remove the return/junction block fuel line clip bolts.
  25. Remove the return/junction block and lines.
  26. Remove the fuel pipe bracket bolts.
  27. Remove the fuel pipe bracket.
  28. Disconnect the fuel inlet pipe from the fuel rail.
  29. Disconnect the fuel inlet pipe from the injection pump.
  30. Remove the inlet fuel pipe.
  31. Prior to removing the fuel injector pipes, use compressed air to blow any debris from between the injector line and fittings. Wipe the fittings clean of debris.
  32. Spray lithium grease, GM P/N 12346293 or equivalent, between the fuel injector line and fittings to assist in containing any debris during removal.
  33. Remove the left fuel injector pipes.
  34. Remove the fuel rail bolts.
  35. Remove the fuel rail and bracket.
  1. Install the fuel rail and bracket.
  2. Install the fuel rail bolts. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
  3. Install the fuel injector pipes. Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  4. After installing the fuel injector pipes, clean the injector pipes and apply sealant GM P/N 97720043, at the fittings to prevent moisture and debris from collecting between the line and fitting.
  5. Remove the inlet fuel pipe.
  6. Connect the fuel inlet pipe to the injection pump.
  7. Connect the fuel inlet pipe to the fuel rail. Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  8. Install the fuel pipe bracket.
  9. Install the fuel pipe bracket bolts. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
  10. Install the return/junction block and lines.
  11. Install the return/junction block fuel line clip bolts. Tighten: Tighten the bolts 25 N.m (18 lb ft).
  12. Install the fuel hose to the fuel rail.
  13. Position the return/junction block hose clamp at the rear of the left fuel rail.
  14. Install the fuel hoses to the return/junction block.
  15. Position the return/junction block hose clamps at the injection pump.
  16. Connect the fuel injector return hose to the return/junction block line.
  17. Install the fuel rail balance pipe.
  18. Connect the fuel rail balance pipe to the fuel rails. Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  19. Install the fuel rail balance pipe bolts. Tighten: Tighten the bolts 25 N.m (18 lb ft).
  20. Install the fuel feed pipe.
  21. Install the fuel feed pipe nut/bolt. Tighten: Tighten the nut/bolt to 25 N.m (18 lb ft).
  22. Install the banjo bolt and washer to the fuel injection control module. Tighten: Tighten the bolt to 40 N.m (29 lb ft).
  23. Position the A/C compressor aside.
  24. Install the A/C compressor bolts. Tighten: Tighten the bolts to 50 N.m (37 lb ft).
  25. Install the PCV hose/pipe. Refer to «Crankcase Ventilation Hoses/Pipes Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  26. Install the fuel line bracket to the stud.
  27. Install the fuel line bracket nut. Tighten: Tighten the nut to 21 N.m (15 lb ft).
  28. Connect the fuel feed and return line quick connect fittings. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__quick-connect-fittings-service-metal-collar) .
  29. Remove the tape from the turbocharger openings.
  30. Install the charged air cooler inlet duct connector (4) to the turbocharger.
  31. Tighten the charged air cooler inlet duct to turbocharger clamp (1). Tighten: Tighten the clamp to 6 N.m (53 lb in).
  32. Position the junction block and bracket.
  33. Install the battery cable junction block bracket bolt (1) to the power steering pump bracket. Tighten: Tighten the bolt to 9 N.m (80 lb in).
  34. Install the water outlet tube. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  35. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  36. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  37. Start the engine. If the engine stalls, repeat the above step.
  38. Once the engine starts, inspect for fuel leaks.
  1. Disconnect the negative battery cables. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  3. Remove the fuel injection control module (FICM). Refer to «Fuel Injection Control Module Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  4. Remove the fuel filter. Refer to «Fuel Filter Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Remove the exhaust gas recirculation (EGR) cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  6. Remove the positive crankcase ventilation (PCV) hose/pipe. Refer to «Crankcase Ventilation Hoses/Pipes Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  7. Disconnect the fuel rail balance pipe from the fuel rails.
  8. Remove the fuel rail balance pipe bolts.
  9. Remove the fuel rail balance pipe.
  10. Prior to removing the fuel injector pipes, use compressed air to blow any debris from between the injector line and fittings. Wipe the fittings clean of debris.
  11. Spray lithium grease, GM P/N 12346293 or equivalent, between the fuel injector line and fittings to assist in containing any debris during removal.
  12. Remove the fuel injector pipes.
  13. Remove the fuel rail bolts.
  14. Remove the fuel rail.
  1. Install the fuel rail.
  2. Install the fuel rail bolts. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
  3. Install the fuel injector pipes. Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  4. After installing the fuel injector pipes, clean the injector pipes and apply sealant GM P/N 97720043, at the fittings to prevent moisture and debris from collecting between the line and fitting.
  5. Install the fuel rail balance pipe.
  6. Connect the fuel rail balance pipe to the fuel rails. Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  7. Install the fuel rail balance pipe bolts. Tighten: Tighten the bolts 25 N.m (18 lb ft).
  8. Install the PCV hose/pipe. Refer to «Crankcase Ventilation Hoses/Pipes Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  9. Install the EGR cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  10. Install the fuel filter. Refer to «Fuel Filter Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  11. Install the FICM. Refer to «Fuel Injection Control Module Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  12. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  13. Connect the negative battery cables. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  14. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  15. Start the engine. If the engine stalls, repeat the above step.
  16. Once the engine starts, inspect for fuel leaks.
  1. Reposition the fuel hose clamp at the return/junction block.
  2. Remove the hose (1) from the return/junction block.
  3. Disconnect the right fuel return line from the return/junction block line.
  4. Reposition the return/junction block hose clamps (3).
  5. Remove the return/junction block hoses.
  6. Remove the return/junction block line clamp bolt (2).
  7. Remove the return/junction block bolt (1).
  8. Remove the return/junction block.
  1. Install the return/junction block.
  2. Install the return/junction block bolt (1).
  3. Install the return/junction block line clamp bolt (2). Tighten: Tighten the bolts to 25 N.m (18 lb ft).
  4. Install the return/junction block hoses.
  5. Position the return/junction block hose clamps (3).
  6. Connect the right fuel return line to the return/junction block line.
  7. Install the hose (1) to the return/junction block.
  8. Position the fuel hose clamp at the return/junction block.
  9. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  10. Start the engine. If the engine stalls, repeat the above step.
  11. Once the engine starts, inspect for fuel leaks.
  1. Remove the air intake pipe. Refer to «Air Intake Pipe Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Disconnect the air conditioning (A/C) compressor clutch electrical connector.
  3. Disconnect the A/C cut out switch electrical connector.
  4. Remove the A/C compressor bolts.
  5. Remove the generator. Refer to «Generator Replacement (4.3L Engine)»(ref-197347-S10903242222005101100000) or «Generator Replacement (4.8L, 5.3L, and 6.0L Engines)»(ref-197347-S00076912952005101100000) or «Generator Replacement (6.6L (LLY) Engine)»(ref-197347-S40758141102005101100000) or «Generator Replacement (8.1L Engine)»(ref-197347-S42024257712005101100000) in Engine Electrical.
  6. Reposition the A/C compressor (with the hoses attached) to the right side of the engine compartment.
  7. Disconnect the main engine electrical harness connectors. Lift up on the latches (1) in order to disconnect the connectors.
  8. Open the harness clip (2).
  9. Remove the main engine electrical harness connectors.
  10. Disconnect the barometric pressure (BARO) sensor electrical connector.
  11. Remove the main engine harness electrical connector bolts.
  12. Remove the main connectors from the bracket.
  13. Disconnect the engine coolant temperature (ECT) sensor electrical connector.
  14. Remove the water outlet tube. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  15. Disconnect the fuel temperature sensor electrical connector.
  16. Disconnect the fuel pressure regulator electrical connector (1).
  17. Disconnect the oil level sensor harness electrical connector.
  18. Reposition the distribution block hose clamps.
  19. Remove the distribution block hoses from the distribution block.
  20. Clean the fuel pressure regulator and high pressure injection pump thoroughly with solvent, such as GM P/N 12377981 (Canadian P/N 10953463) or equivalent.
  21. Using compressed air, thoroughly blow dry the regulator and pump.
  22. Remove the 3 fuel pressure regulator screws (1) using a T25 TORX®.
  23. Remove the fuel pressure regulator (1).
  24. If dirt or debris is found in the bore or seating surfaces of the fuel injection pump, perform the following: Place a clean rag over the bore on order to collect the excess fuel. Bump the engine over in order to flush any debris out of the regulator bore.
IMPORTANTIf the pressure regulator is being re-used, check the O-rings for damage. If the O-rings are damaged, install NEW O-rings.
  1. Lubricate and install NEW O-rings onto the regulator. Lubricate the O-rings with clean, NEW engine oil.
  2. Install the fuel pressure regulator (1).
  3. Install the 3 fuel pressure regulator screws (1) using a T25 TORX®. Tighten: Tighten the screws a first pass to 4 N.m (35 lb in). Tighten the screws a final pass to 7 N.m (62 lb in).
  4. Install the distribution block hoses to the distribution block.
  5. Position the distribution block hose clamps.
  6. Connect the oil level sensor harness electrical connector.
  7. Connect the fuel pressure regulator electrical connector (1).
  8. Connect the fuel temperature sensor electrical connector.
  9. Install the water outlet tube. Refer to «Water Outlet Tube Replacement (6.6L (LLY) Engine)»(ref-197356-S13467457222005101100000) in Engine Cooling.
  10. Connect the ECT sensor electrical connector.
  11. Install the main connectors to the bracket.
  12. Install the main engine harness electrical connector bolts. Tighten: Tighten the bolts to 21 N.m (15 lb ft).
  13. Connect the BARO sensor electrical connector.
  14. Connect the main engine electrical harness connectors.
  15. Push down on the latches (1) in order to connect the connectors.
  16. Close the harness clip (2).
  17. Position the A/C compressor.
  18. Install the A/C compressor bolts. Tighten: Tighten the bolts to 50 N.m (37 lb ft).
  19. Connect the A/C cut out switch electrical connector.
  20. Connect the A/C compressor clutch electrical connector.
  21. Install the generator. Refer to «Generator Replacement (4.3L Engine)»(ref-197347-S10903242222005101100000) or «Generator Replacement (4.8L, 5.3L, and 6.0L Engines)»(ref-197347-S00076912952005101100000) or «Generator Replacement (6.6L (LLY) Engine)»(ref-197347-S40758141102005101100000) or «Generator Replacement (8.1L Engine)»(ref-197347-S42024257712005101100000) in Engine Electrical.
  22. Install the air intake pipe. Refer to «Air Intake Pipe Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  23. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  24. Start the engine. If the engine stalls, repeat the above step.
  25. Once the engine starts, inspect for fuel leaks.

Fuel Pressure Relief Valve Replacement

At this time the fuel pressure relief valve is serviced as part of the fuel rail. Refer to Fuel Rail Assembly Replacement - Bank 1 .

  1. Remove the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  2. Disconnect negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  3. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  4. Remove the fuel injection control module. Refer to «Fuel Injection Control Module Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Drain the cooling system. Refer to «Draining and Filling Cooling System (w/RPO HP2)»(ref-197356-S32653343972005101100000) or «Draining and Filling Cooling System (w/o RPO HP2)»(ref-197356-S16321664992005101100000) .
  6. Remove the fan. Refer to «Fan Replacement»(ref-197356-S07457687482005101100000) in Engine Cooling.
  7. Remove the battery cable junction block bolt (1) from the power steering pump bracket.
  8. Reposition the battery cables out of the way.
  9. Disconnect the air conditioning (A/C) compressor clutch electrical connector.
  10. Disconnect the A/C cut out switch electrical connector.
  11. Remove the A/C compressor bolts.
  12. Reposition the A/C compressor, with the hoses attached, to the right side of the engine compartment.
  13. Remove the power steering pump bracket rear bolts (1).
  14. Reposition the power steering pump, with the hoses attached, to the right side of the engine compartment.
  15. Remove the A/C compressor/power steering pump bracket bolts and bracket.
  16. Remove the heater outlet hose bolt from the generator bracket.
  17. Remove the drive belt tensioner and bolt.
  18. Remove the generator. Refer to «Generator Replacement (4.3L Engine)»(ref-197347-S10903242222005101100000) or «Generator Replacement (4.8L, 5.3L, and 6.0L Engines)»(ref-197347-S00076912952005101100000) or «Generator Replacement (6.6L (LLY) Engine)»(ref-197347-S40758141102005101100000) or «Generator Replacement (8.1L Engine)»(ref-197347-S42024257712005101100000) in Engine Electrical.
  19. Remove the generator bracket bolts and bracket.
  20. Remove the thermostat housing crossover. Refer to «Thermostat Housing Crossover Replacement (6.6L (LLY) Engine)»(ref-197356-S02919999392005101100000) in Engine Cooling.
  21. Disconnect the fuel balance pipe fitting from the right fuel rail.
  22. Remove the fuel balance pipe retainer bolts.
  23. Disconnect the fuel rail inlet pipe from the injection pump and rail.
  24. Remove the inlet pipe.
  25. Remove the center intake manifold. Refer to «Intake Manifold Replacement - Center»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  26. Reposition the injection pump hose clamps at the fuel line.
  27. Remove the hoses from fuel lines.
  28. Remove the fuel injection pump bolts.
  29. Remove the fuel injection pump from the block. Use 2 screwdrivers to work the pump from the block towards the rear of engine keeping the pump straight.
  30. The fuel injection pump may need to be rotated in order to remove it from the vehicle.

Preparing The Fuel Injection Pump

  1. Hold the fuel pump by the drive gear in a vice with copper jaw liners.
  2. Loosen the gear nut until the nut is even with the end of the gear shaft.
  3. Remove the gear from the tapered shaft of the injection pump.
  4. Separate the injection pump and adapter by removing the 3 bolts and spacers.
  5. Inspect the O-ring for damage on the pump adapter and replace, if necessary. Lubricate the O-ring with clean engine oil.
  6. Clean all mating surfaces.
  7. Install the adapter on the pump. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  8. Install the 3 bolts and spacers. Tighten: Tighten the bolts to 20 N.m (15 lb ft).
  9. Install the gear and nut. Tighten: Tighten nut to 70 N.m (52 lb ft).
  1. Install the fuel injection pump to the block.
  2. Install the fuel injection pump bolts. Tighten: Tighten the bolts to 21 N.m (15 lb ft).
  3. Install the hoses to fuel lines.
  4. Position the injection pump hose clamps at the fuel line.
  5. Install the center intake manifold. Refer to «Intake Manifold Replacement - Center»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  6. Install the inlet pipe.
  7. Connect the fuel rail inlet pipe to the injection pump and rail. Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  8. Connect the fuel balance pipe fitting to the right fuel rail. Tighten: Tighten the fitting to 41 N.m (30 lb ft).
  9. Install the fuel balance pipe retainer bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
  10. Install the thermostat housing crossover. Refer to «Thermostat Housing Crossover Replacement (6.6L (LLY) Engine)»(ref-197356-S02919999392005101100000) in Engine Cooling.
  11. Install the generator bracket and bolts. Tighten: Tighten the bolts to 46 N.m (34 lb ft).
  12. Install the generator. Refer to «Generator Replacement (4.3L Engine)»(ref-197347-S10903242222005101100000) or «Generator Replacement (4.8L, 5.3L, and 6.0L Engines)»(ref-197347-S00076912952005101100000) or «Generator Replacement (6.6L (LLY) Engine)»(ref-197347-S40758141102005101100000) or «Generator Replacement (8.1L Engine)»(ref-197347-S42024257712005101100000) in Engine Electrical.
  13. Install the drive belt tensioner and bolt. Tighten: Tighten the bolt to 50 N.m (37 lb ft).
  14. Install the heater outlet hose bolt to the generator bracket Tighten: Tighten the bolt to 21 N.m (15 lb ft).
  15. Install the oil level indicator tube bracket bolt. Tighten: Tighten the bolt to 21 N.m (15 lb ft).
  16. Install the A/C compressor/power steering pump bracket and bolts. Tighten: Tighten the bolt to 46 N.m (34 lb ft).
  17. Position the power steering pump, with the hoses attached, to the bracket.
  18. Install the power steering pump bracket rear bolts (1). Tighten: Tighten the bolts to 50 N.m (37 lb ft).
  19. Position the A/C compressor, with the hoses attached, to the bracket.
  20. Install the A/C compressor bolts. Tighten: Tighten the bolts to 50 N.m (37 lb ft).
  21. Connect the A/C cut out switch electrical connector.
  22. Connect the A/C compressor clutch electrical connector.
  23. Position the battery cables to the bracket.
  24. Install the battery cable junction block bolt to the power steering pump bracket. Tighten: Tighten the bolts to 9 N.m (80 lb in).
  25. Install the fan. Refer to «Fan Replacement»(ref-197356-S07457687482005101100000) in Engine Cooling.
  26. Install the fuel injection control module. Refer to «Fuel Injection Control Module Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  27. Fill the cooling system. Refer to «Draining and Filling Cooling System (w/RPO HP2)»(ref-197356-S32653343972005101100000) or «Draining and Filling Cooling System (w/o RPO HP2)»(ref-197356-S16321664992005101100000) in Engine Cooling.
  28. Install the air cleaner outlet duct. Refer to «Crankcase Ventilation Hoses/Pipes Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) .
  29. Connect negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  30. Install the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  31. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  32. Start the engine. If the engine stalls, repeat the above step.
  33. Once the engine starts, inspect for fuel leaks.

J-46594 Fuel Injector Remover

  1. Remove the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  2. Drain the cooling system. Refer to «Draining and Filling Cooling System (w/RPO HP2)»(ref-197356-S32653343972005101100000) or «Draining and Filling Cooling System (w/o RPO HP2)»(ref-197356-S16321664992005101100000) in Engine Cooling.
  3. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  4. Loosen the charged air cooler inlet duct connector to turbocharger clamp (1).
  5. Remove the charged air cooler inlet duct connector (4) from the turbocharger.
  6. Disconnect the main engine electrical harness connectors. Lift up on the latches (1) in order to disconnect the connectors.
  7. Open the harness clip (2).
  8. Remove the main engine electrical harness connectors.
  9. Remove the engine harness main electrical connectors bolts.
  10. Remove the main electrical connectors from the bracket.
  11. Disconnect the barometric sensor electrical connector.
  12. Remove the engine wire harness from the clip.
  13. Remove the main electrical harness bracket bolts.
  14. Remove the main electrical harness bracket.
  15. Disconnect the glow plug controller electrical connector.
  16. Disconnect the glow plug controller battery feed electrical connector (1).
  17. Remove the positive crankcase ventilation (PCV) hose/pipe. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  18. Prior to removing the fuel injector pipes, use compressed air to blow any debris from between the injector line and fittings. Wipe the fittings clean of debris.
  19. Spray lithium grease, GM P/N 12346293 or equivalent, between the fuel injector line and fittings to assist in containing any debris during removal.
  20. Remove the left fuel injector pipes.
  21. Remove the fuel return hose clips.
  22. Remove the fuel return hose from the injectors.
  23. Disconnect the fuel injector electrical connectors.
  24. Remove the fuel injector bracket bolts.
  25. Install J-46594 into the bolt hole in the fuel injector bracket.
  26. Install a flare nut wrench onto J-46594 and pull back away from the fuel injector, until the injector releases from its seat.
  27. Remove J-46594 .
  28. Remove the fuel injectors with brackets.
  29. If necessary, remove the fuel injector bracket pins.
  30. If necessary, remove and discard the copper washer from the fuel injector bore.
  31. If necessary, remove and discard the O-ring from the fuel injector.

Fuel Injector Cleaning and Inspection

IMPORTANTIf reusing the old injectors perform the following
  1. Use a soft bristle non-metallic brush and top engine cleaner, GM P/N 1052626 or equivalent, to remove any deposits from the nozzle tip (1) and the copper washer sealing area (2) before re-installation.
  2. Inspect the fuel injector nozzle tip (1) for any signs of discoloration (dark yellow, tan or blue) due to excessive heat.
  3. Replace the injector if any damage is found.
  4. Clean the fuel injector high pressure line.
  5. Inspect the fuel injector line for excessive corrosion or damage to the sealing surfaces (1, 2). Replace the line if any damage is found.
  1. If necessary, install a NEW O-ring onto the fuel injector.
  2. If necessary, install a NEW copper washer to the fuel injector bore.
  3. If necessary, install the fuel injector bracket pins.
  4. Install the fuel injectors with brackets.
  5. Install the fuel injector bracket bolts. Tighten: Tighten the bolts to 30 N.m (22 lb ft).
  6. Connect the fuel injector electrical connectors.
  7. Install the fuel return hose to the injectors.
  8. Install the fuel return hose clips.
  9. Install the fuel injector pipes. Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  10. After installing the fuel injector pipes, clean the injector pipes and apply sealant GM P/N 97720043, at the fittings to prevent moisture and debris from collecting between the line and fitting.
  11. Install the PCV hose/pipe. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  12. Connect the glow plug controller battery feed electrical connector (1).
  13. Connect the glow plug controller electrical connector.
  14. Install the main electrical harness bracket.
  15. Install the main electrical harness bracket bolts. Tighten: Tighten the bolts to 21 N.m (15 lb ft).
  16. Connect the barometric sensor electrical connector.
  17. Install the engine wire harness to the clip.
  18. Install the main electrical connectors to the bracket.
  19. Install the engine harness main electrical connectors bolts. Tighten: Tighten the bolts to 21 N.m (15 lb ft).
  20. Connect the main engine electrical harness connectors.
  21. Push down on the latches (1) in order to connect the connectors.
  22. Close the harness clip (2).
  23. Remove the tape from the turbocharger openings.
  24. Install the charged air cooler inlet duct connector (4) to the turbocharger.
  25. Tighten the charged air cooler inlet duct connector to turbocharger clamp (1). Tighten: Tighten the clamp to 6 N.m (53 lb in).
  26. Fill the cooling system. Refer to «Draining and Filling Cooling System (w/RPO HP2)»(ref-197356-S32653343972005101100000) or «Draining and Filling Cooling System (w/o RPO HP2)»(ref-197356-S16321664992005101100000) in Engine Cooling.
  27. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  28. Install the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  29. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  30. Start the engine. If the engine stalls, repeat the above step.
  31. Once the engine starts, inspect for fuel leaks.

J-46594 Fuel Injector Remover

  1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Loosen the charged air cooler outlet duct to intake hose clamp. IMPORTANT: Do not use a screwdriver or other tool to pry the hose loose. The hose can be torn or damaged. Loosen the hose by twisting.
  3. Remove the charged air cooler outlet duct from the intake.
  4. Remove the fuel filter and bracket. Refer to «Fuel Filter Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Remove the fuel injection control module (FICM). Refer to «Fuel Injection Control Module Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  6. Prior to removing the fuel injector pipes, use compressed air to blow any debris from between the injector line and fittings. Wipe the fittings clean of debris.
  7. Spray lithium grease, GM P/N 12346293 or equivalent, between the fuel injector line and fittings to assist in containing any debris during removal.
  8. Remove the fuel injector pipes.
  9. Remove the fuel return hose clips.
  10. Remove the fuel return hose from the injectors.
  11. Disconnect the fuel injector electrical connectors.
  12. Remove the fuel injector bracket bolts.
  13. Install J-46594 into the bolt hole in the fuel injector bracket.
  14. Install a flare nut wrench onto J-46594 and pull back away from the fuel injector, until the injector releases from its seat.
  15. Remove J-46594 .
  16. Remove the fuel injectors with brackets.
  17. If necessary, remove the fuel injector bracket pins.
  18. If necessary, remove and discard the copper washer from the fuel injector bore.
  19. If necessary, remove and discard the O-ring from the fuel injector.
IMPORTANTIf reusing the old injectors perform the following
  1. Use a soft bristle non-metallic brush and top engine cleaner, GM P/N 1052626 or equivalent, to remove any deposits from the nozzle tip (1) and the copper washer sealing area (2) before re-installation.
  2. Inspect the fuel injector nozzle tip (1) for any signs of discoloration (dark yellow, tan or blue) due to excessive heat.
  3. Replace the injector if any damage is found.
  4. Clean the fuel injector high pressure line.
  5. Inspect the fuel injector line for excessive corrosion or damage to the sealing surfaces (1, 2). Replace the line if any damage is found.
  1. If necessary, install a NEW O-ring onto the fuel injector.
  2. If necessary, install a NEW copper washer to the fuel injector bore.
  3. If necessary, install the fuel injector bracket pins.
  4. Install the fuel injectors with brackets.
  5. Install the fuel injector bracket bolts. Tighten: Tighten the bolts to 30 N.m (22 lb ft).
  6. Connect the fuel injector electrical connectors.
  7. Install the fuel return hose to the injectors.
  8. Install the fuel return hose clips.
  9. Install the fuel injector pipes. Tighten: Tighten the fittings to 41 N.m (30 lb ft).
  10. After installing the fuel injector pipes, clean the injector pipes and apply sealant GM P/N 97720043, at the fittings to prevent moisture and debris from collecting between the line and fitting.
  11. Install the FICM. Refer to «Fuel Injection Control Module Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  12. Install the fuel filter with bracket. Refer to «Fuel Filter Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  13. Install the charged air cooler outlet duct from the intake.
  14. Tighten the charged air cooler outlet duct to intake hose clamp. Tighten: Tighten the clamp to 6 N.m (53 lb in).
  15. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  16. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  17. Start the engine. If the engine stalls, repeat the above step.
  18. Once the engine starts, inspect for fuel leaks.
  1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Remove the exhaust gas recirculation (EGR) cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  3. Disconnect the fuel rail pressure sensor electrical connector.
  4. Prior to removal, clean the fuel pressure sensor and surrounding area thoroughly with solvent, such as GM P/N 12377981 (Canadian P/N 10953463) or equivalent.
  5. Using compressed air, thoroughly blow dry the sensor and surrounding area.
  6. Remove the fuel pressure sensor (1).
  1. Install the fuel pressure sensor (1). Tighten: Tighten the sensor to 70 N.m (52 lb ft).
  2. Connect the fuel rail pressure sensor electrical connector.
  3. Install the EGR cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  4. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  5. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  6. Start the engine. If the engine stalls, repeat the above step.
  7. Once the engine starts, inspect for fuel leaks.
  1. Remove the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical.
  2. Loosen the charged air cooler inlet duct connector to turbocharger clamp (1).
  3. Remove the charged air cooler inlet duct connector (4) from the turbocharger.
  4. Disconnect the fuel temperature sensor electrical connector.
  5. Remove the fuel temperature sensor.
  1. Install the fuel temperature sensor. Tighten: Tighten the sensor to 22 N.m (16 lb ft).
  2. Connect the fuel temperature sensor electrical connector.
  3. Remove the tape from the turbocharger openings.
  4. Install the charged air cooler inlet duct connector (4) to the turbocharger.
  5. Tighten the charged air cooler inlet duct connector to turbocharger clamp (1). Tighten: Tighten the clamp to 6 N.m (53 lb in).
  6. Install the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical.
  7. Prime the fuel system. Refer to «Fuel System Priming»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction__fuel-system-priming) .
  8. Start the engine. If the engine stalls, repeat the above step.
  9. Once the engine starts, inspect for fuel leaks.
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Remove the left wheelhouse panel. Refer to «Wheelhouse Panel Replacement»(ref-197355-S26734560152005101100000) in Body Front End.
  3. Remove the glow plug harness nut(s).
  4. Remove the harness from the glow plug(s).
  5. Remove the glow plug(s).
  1. Install the glow plug(s). Tighten: Tighten the plug to 18 N.m (13 lb ft).
  2. Install the harness to the glow plug(s).
  3. Install the glow plug harness nut(s). Tighten: Tighten the nut to 1.7 N.m (15 lb in).
  4. Install the left wheelhouse panel. Refer to «Wheelhouse Panel Replacement»(ref-197355-S26734560152005101100000) in Body Front End.
  5. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Remove the right wheelhouse panel. Refer to «Wheelhouse Panel Replacement»(ref-197355-S26734560152005101100000) in Body Front End.
  3. Remove the glow plug harness nut(s).
  4. Remove the harness from the glow plug(s).
  5. Remove the glow plug(s).
  1. Install the glow plug(s). Tighten: Tighten the plug to 18 N.m (13 lb ft).
  2. Install the harness to the glow plug(s).
  3. Install the glow plug harness nut(s). Tighten: Tighten the nut to 1.7 N.m (15 lb in).
  4. Install the right wheelhouse panel. Refer to «Wheelhouse Panel Replacement»(ref-197355-S26734560152005101100000) in Body Front End.
  5. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Disconnect the glow plug controller electrical connector.
  3. Disconnect the glow plug controller battery feed electrical connector (1).
  4. Remove the glow plug controller bolts.
  5. Remove the glow plug controller.
  1. Install the glow plug controller.
  2. Install the glow plug controller bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
  3. Connect the glow plug controller battery feed electrical connector (1).
  4. Connect the glow plug controller electrical connector.
  5. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  2. Remove the right wheelhouse panel. Refer to «Wheelhouse Panel Replacement»(ref-197355-S26734560152005101100000) in Body Front End.
  3. Disconnect the crankshaft position (CKP) sensor electrical connector.
  4. Remove the CKP sensor bolt.
  5. Remove the CKP sensor.
  6. If necessary, remove the CKP sensor spacer bolts.
  7. If necessary, remove the CKP sensor spacer.
  1. If necessary, lubricate a NEW CKP spacer O-ring with clean engine oil.
  2. If necessary, install the NEW O-ring to the CKP sensor spacer. IMPORTANT: The crankshaft position sensor spacers are machined with different timing positions. However, if the crankshaft position sensor spacer requires replacement, replace with a grade "C" spacer.
  3. If necessary, install the CKP sensor spacer. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  4. If necessary, install the CKP sensor spacer bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
  5. Lubricate a NEW CKP sensor O-ring with clean engine oil.
  6. Install the NEW O-ring to the CKP sensor.
  7. Install the CKP sensor.
  8. Install the CKP sensor bolt. Tighten: Tighten the bolt to 10 N.m (89 lb in).
  9. Connect the CKP sensor electrical connector.
  10. Install the right wheelhouse panel. Refer to «Wheelhouse Panel Replacement»(ref-197355-S26734560152005101100000) in Body Front End.
  11. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-197347-S01049574002005101100000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-197347-S39973143602005101100000) in Engine Electrical.
  1. Remove the cooling fan pulley. Refer to «Cooling Fan Pulley Replacement (6.6L (LLY) Engine)»(ref-197356-S32480144412005101100000) in Engine Cooling.
  2. Remove the camshaft position (CMP) sensor bolt.
  3. Remove the CMP sensor.
  1. Lubricate the CMP sensor O-ring with clean engine oil.
  2. Install the CMP sensor. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  3. Install the CMP sensor bolt. Tighten: Tighten the bolt to 10 N.m (89 lb in).
  4. Install the cooling fan pulley. Refer to «Cooling Fan Pulley Replacement (6.6L (LLY) Engine)»(ref-197356-S32480144412005101100000) in Engine Cooling.
  1. Remove the exhaust gas recirculation (EGR) cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Remove the EGR valve bolts (3).
  3. Remove the EGR valve/solenoid assembly (1).
  4. Remove and discard the EGR valve/solenoid assembly gasket (2).
  1. Install a NEW EGR valve/solenoid assembly gasket (2).
  2. Install the EGR valve/solenoid assembly (1). NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  3. Install the EGR valve bolts. Tighten: Tighten the bolts to 20 N.m (15 lb ft).
  4. Install the EGR cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  1. Remove the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  3. Loosen the charged air cooler outlet duct to intake hose clamp. IMPORTANT: Do not use a screwdriver or other tool to pry the hose loose. The hose can be torn or damaged. Loosen the hose by twisting.
  4. Remove the charged air cooler outlet duct from the intake.
  5. Drain the cooling system. Refer to «Draining and Filling Cooling System (w/RPO HP2)»(ref-197356-S32653343972005101100000) or «Draining and Filling Cooling System (w/o RPO HP2)»(ref-197356-S16321664992005101100000) in Engine Cooling.
  6. Remove the positive crankcase ventilation (PCV) hose/pipe. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  7. If necessary, remove the tie strap from the electrical harness.
  8. Remove the air inlet tube to intake manifold tube bolt and nut.
  9. Remove the air inlet tube nuts.
  10. Remove the air inlet tube.
  11. Disconnect the exhaust gas recirculation (EGR) valve electrical connector.
  12. Disconnect the EGR cooler tube heater hose.
  13. Remove the EGR coolant pipe bolts.
  14. Remove the EGR coolant pipe.
  15. Remove the rear EGR cooler tube bolts.
  16. Remove the EGR cooler tube bolts.
  17. Remove the EGR cooler tube.
  1. Install the EGR cooler tube.
  2. Install the EGR cooler tube bolts. Tighten: Tighten the bolts to 50 N.m (37 lb ft).
  3. Install the rear EGR cooler tube bolts. Tighten: Tighten the bolts to 20 N.m (15 lb ft).
  4. Install the EGR coolant pipe.
  5. Install the EGR coolant pipe bolts. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
  6. Connect the EGR cooler tube heater hose.
  7. Connect the EGR valve electrical connector.
  8. Install the air inlet tube.
  9. Install the air inlet tube nuts. Tighten: Tighten the nuts to 25 N.m (18 lb ft).
  10. Install the air inlet tube to intake manifold tube bolt and nut. Tighten: Tighten the bolt/nut to 10 N.m (89 lb in).
  11. If necessary, install a tie strap to the electrical harness.
  12. Install the PCV hose/pipe. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  13. Install the charged air cooler outlet duct to the intake.
  14. Tighten the charged air cooler outlet duct to intake hose clamp. Tighten: Tighten the clamp to 6 N.m (53 lb in).
  15. Install the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  16. Fill the cooling system. Refer to «Draining and Filling Cooling System (w/RPO HP2)»(ref-197356-S32653343972005101100000) or «Draining and Filling Cooling System (w/o RPO HP2)»(ref-197356-S16321664992005101100000) in Engine Cooling.

Exhaust Gas Recirculation (EGR) System Cleaning

CAUTIONAvoid breathing fumes and swallowing EGR exhaust deposits when removing components for cleaning as bodily injury may result.
  1. Remove the exhaust gas recirculation (EGR) cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  2. Depress the pintle several times using a pencil eraser or other suitable soft instrument. The pintle should move in and out smoothly. Replace the valve if the valve exhibits tendencies to stick.
  3. Try to rotate the EGR valve electrical connector housing. Repeat for the coil housing. Replace the valve if the valve exhibits any looseness. Inspect the EGR valve pintle and seat for deposits. Use a cloth or other suitable soft device to remove the deposits. Remove all loose particles. Replace the valve if the deposits are such that the pintle to base interface cannot be cleaned adequately to allow the pintle to seal against the seat. Damage to the powdered metal EGR valve base occurs if cleaned with solvents, sharp tools, wire brush or wheel, or sand blasting. Cleaning by these methods is not recommended.
  4. Clean the passages with a wire brush. Remove all loose particles.
  5. Install the EGR cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  1. Remove the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  2. Remove the turbocharger oil feed pipe banjo bolt and washer.
  3. Reposition the oil feed pipe out of the way.
  4. Disconnect the turbocharger vane control solenoid valve electrical connector.
  5. Remove the vane control solenoid valve bracket bolt and bracket.
  6. Remove the turbocharger vane control solenoid valve from the turbocharger.
  1. Install the turbocharger vane control solenoid valve to the turbocharger.
  2. Install the vane control solenoid valve bracket and bolt. Tighten: Tighten the bolt to 23 N.m (17 lb ft).
  3. Connect the turbocharger vane control solenoid valve electrical connector.
  4. Position the oil feed pipe to the turbocharger.
  5. Install a NEW turbocharger oil feed pipe washer and the banjo bolt. Tighten: Tighten the bolt to 34 N.m (25 lb ft).
  6. Install the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  7. Perform the turbocharger learn procedure. Refer to «Turbocharger Learn Procedure»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  1. Remove the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  2. Disconnect the turbocharger vane position sensor electrical connector.
  3. Remove the turbocharger vane position sensor connector from the bracket.
  4. Remove the turbocharger vane position sensor from the turbocharger.
  1. Install the turbocharger vane position sensor to the turbocharger. Tighten: Tighten the sensor to 28 N.m (21 lb ft).
  2. Install the turbocharger vane position sensor connector to the bracket.
  3. Connect the turbocharger vane position sensor electrical connector.
  4. Install the thermal reflective shield/tape, refer to the following procedure.

Thermal Reflective Shield/Tape Installation

IMPORTANTEnsure outside surface of sensor body is clean and oil-free prior to beginning the installation procedure. If sensor body surface is oily, use a mild degreaser in order to remove the oil from the surface. Ensure degreased surface is dry prior to beginning the installation. The thermal reflective shield and tie strap are to be installed over the vane position sensor AFTER the sensor is installed and torqued in the turbo centerhousing. Graphics below show the sensor prior to the installation process for clarity purposes only.
  1. Peel off the protective backing from the back side of the thermal reflective shield/tape.
  2. With the sticky side of the shield/tape applied against the sensor body, align the bottom edge of the shield/tape with the bottom edge of the hex, and begin wrapping the sensor.
  3. Completely wrap the shield/tape around the sensor.
  4. Tuck the top of the shield/tape under the head of the brass cable crimp sleeve all around, allowing the shield/tape to fold over and overlap itself at the top.
  5. The top of the shield/tape is now shown tucked under the head of the brass cable crimp sleeve all around.
  6. Wrap the tie strap around the necked porting of the sensor body just above the hex. Insert the end of the strap in the buckle and tighten by pulling the end with needle nose pliers.
  7. Bend the end of the tie strap 180 degrees over the top of the buckle.
  8. Cut off the tie strap using side cutters so that the cut end will lie approximately over the center of the buckle. Push down the end of the tie strap over the buckle in order to minimize protrusion of the cut end or any sharp edges.
  9. Finished installation is shown.
  10. Install the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  11. Perform the turbocharger learn procedure. Refer to «Turbocharger Learn Procedure»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .

Circuit Description

The turbocharger (TC) learns the vane positions automatically during each ignition cycle. The engine control module (ECM) performs the turbocharger learn procedure automatically when the enable criteria are met. After each ignition cycle, and before the enable criteria ha been met, the ECM will use the previously learned value. If the ECM does not have a previously learn value, it will default to a stored calibrated value. The ECM will use this value until the enable criteria have been met. It will then perform this procedure to learn the new value. If the ECM attempts to perform the learn procedure and fails, DTCs P0046 or P2563 may set.

The turbocharger learn procedure must be performed manually with a Tech 2 when any turbocharger system service has been performed. Certain enable criteria must be met for the ECM to perform this procedure.

The turbocharger learn procedure is required when the following service procedures have been performed

  1. The turbocharger vane position control solenoid valve replacement
  2. The turbocharger vane position sensor replacement
  3. The engine control module (ECM) replacement
  4. The turbocharger replacement
  5. Any service that disturbs the turbocharger components

Learn Procedure

IMPORTANTOnce the enable conditions have been met the throttle must remain at idle. Do not change the accelerator pedal position (APP) during this procedure.
  1. The following conditions must be met for the ECM to perform the turbocharger learn procedure: The A/C is OFF. The vehicle is in Park or Neutral. Start and idle the engine. The engine coolant temperature (ECT) is more than 40°C (104°F).
  2. After the enable conditions have been met and the engine idle is stabilized, enter the TC Learn Output function from the Engine Output Control Menu. Command the TC Vane Position Sensor ON for at least 5 seconds, then command it OFF. The system should have learned the new turbocharger position. The TC Learned parameter should have toggled from No to Yes.
  1. Disconnect the mass air flow (MAF)/intake air temperature (IAT) sensor electrical connector (1).
  2. Loosen the screws holding the air cleaner housing halves together.
  3. Separate the housing halves and remove the air filter element.
  1. Install the air filter element into the lower air cleaner housing.
  2. Install the upper housing cover and tighten the screws. Tighten: Tighten the screws to 4 N.m (35 lb in).
  3. Connect the MAF/IAT sensor electrical connector (1).
  1. Disconnect the mass air flow (MAF)/intake air temperature (IAT) sensor electrical connector (1).
  2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  3. Grasp the air filter assembly (1) and pull up on the assembly in order to disengage the retaining pins (2) from the grommets (3).
  1. Line up the retaining pins (2) with the grommets (3).
  2. Install the air cleaner assembly until the air cleaner is seated fully on the mounts and is up against the fender apron.
  3. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  4. Connect the MAF/IAT sensor electrical connector (1).
  1. Loosen the outlet duct clamps at the turbocharger and the mass air flow (MAF)/intake air temperature (IAT) sensor.
  2. Remove the air cleaner outlet duct.
  1. Install the air cleaner outlet duct.
  2. Tighten the outlet duct clamps at the turbocharger and the MAF/IAT sensor. Tighten: Tighten the clamps to 4 N.m (35 lb in).
  1. Remove the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  3. Remove the positive crankcase ventilation (PCV) hose/pipe. Refer to «Crankcase Ventilation Hoses/Pipes Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  4. Disconnect the turbocharger electrical connector. Lift the metal retainer, in order to disconnect.
  5. Remove the engine wire harness clamp bolt and reposition.
  6. Loosen the air intake pipe to turbocharger clamp (1).
  7. Remove the air intake pipe (2) from the turbocharger.
  1. Clean the mating surfaces on the air intake pipe (2) and the turbocharger.
  2. Align the air intake pipe (2) to the turbocharger. NOTE: Refer to «Fastener Notice»(ref-197335-S17275608472005101100000) in Cautions and Notices.
  3. Tighten the air intake pipe to turbocharger clamp (1). Tighten: Tighten the clamp to 4.6 N.m (41 lb in).
  4. Install the engine wire harness clamp bolt. Tighten: Tighten the bolt to 10 N.m (89 lb in).
  5. Connect the turbocharger electrical connector.
  6. Install the PCV hose/pipe. Refer to «Crankcase Ventilation Hoses/Pipes Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).
  7. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-introduction) .
  8. Install the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) in Engine Mechanical - 6.6L (LLY).

Engine Control Module (ECM) Description

The engine control module (ECM) processes the various input information. The ECM sends the necessary electrical responses to control fuel delivery.

The input information has an interrelation to more than one output. One failed input can affect more than one systems operation.

Diagnostic System Check - Vehicle

The Diagnostic System Check - Vehicle is an organized approach to identify a problem caused by an electronic engine control system malfunction. This diagnostic check must be the starting point for any driveability complaint diagnosis. The diagnostic directs the technician to the next logical step in diagnosing the complaint.

Use the Engine Scan Tool Data Definitions list for a comparison after fulfilling the following items

  1. Complete the Diagnostic System Check - Vehicle.
  2. Confirm that the on-board diagnostics are functioning properly.
  3. Confirm there are no diagnostic trouble codes.

The Engine Scan Tool Definitions are an average of display values recorded from normal operating vehicles. The definitions intend to represent what a normal functioning system should display.

IMPORTANTDo not use a scan tool that displays faulty data. Report the problem to the manufacturer. Using a malfunctioning scan tool can result in misdiagnosis and unnecessary parts replacement. Use only the parameters listed in the Engine Scan Tool Data Definitions for diagnosis. When a scan tool reads other parameters, General Motors recommends not using the values for use in diagnosis. For more description on the values and the use of the scan tool to diagnose the engine control module (ECM) inputs, refer to the applicable diagnostic. When all the values are within the range illustrated in the Engine Scan Tool Data Definitions, refer to Symptoms - Engine Controls .

Control Module Communications

The control module system has a computer, the engine control module (ECM), to control fuel delivery, timing, and some emission control systems. The control module system monitors a number of engine and vehicle functions and controls the following operations through the fuel injection control module (FICM)

  1. Fuel rail pressure
  2. Fuel injector
  3. Fuel injector pulse width

The diesel ECM, located in the engine compartment, is the control center of the control module system. The engine control module used on the electronic fuel injected 6.6L diesel is referred to as a ECM.

The ECM constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The ECM performs the diagnostic function of the system. The ECM can recognize operational problems, alert the driver through the malfunction indicator lamp (MIL) - Service Engine Soon, and store one or more diagnostic trouble codes (DTCs) which identify the problem areas to aid the technician in making repairs. See the specific diagnosis procedure for more information.

Malfunction Indicator Lamp (MIL) Operation

The malfunction indicator lamp (MIL) is located in the instrument panel cluster. The MIL will display as either SERVICE ENGINE SOON or one of the following symbols when commanded ON

Scheme 26

Scheme 26: Malfunction Indicator Lamp (MIL) Operation
Scheme 26: Malfunction Indicator Lamp (MIL) Operation

Scheme 27

Scheme 27
Scheme 27

The MIL indicates that an emissions related fault has occurred and vehicle service is required.

The following is a list of the modes of operation for the MIL

  1. The MIL illuminates when the ignition is turned ON, with the engine OFF. This is a bulb test to ensure the MIL is able to illuminate.
  2. The MIL turns OFF after the engine is started if a diagnostic fault is not present.
  3. The MIL remains illuminated after the engine is started if the control module detects a fault. A diagnostic trouble code (DTC) is stored any time the control module illuminates the MIL due to an emissions related fault. The MIL turns OFF after three consecutive ignition cycles in which a Test Passed has been reported for the diagnostic test that originally caused the MIL to illuminate.
  4. The MIL flashes if the control module detects a misfire condition which could damage the catalytic converter.
  5. When the MIL is illuminated and the engine stalls, the MIL will remain illuminated as long as the ignition is ON.
  6. When the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition is cycled OFF and then ON.

Aftermarket (Add-On) Electrical And Vacuum Equipment

Any equipment installed on a vehicle after leaving the factory that connects to the electrical or vacuum systems of the vehicle defines aftermarket (Add-On) electrical and vacuum equipment. The vehicle design makes no allowances for this type of equipment.

Note. Do not attach add-on vacuum operated equipment to this vehicle. The use of add-on vacuum equipment may result in damage to vehicle components or systems.

Note. Connect any add-on electrically operated equipment to the vehicle's electrical system at the battery (power and ground) in order to prevent damage to the vehicle.

The add-on electrical equipment, even when installed to these strict guidelines, may still cause the powertrain system to malfunction. This may also include any equipment which is not connected to the electrical system of the vehicle such as portable telephones and radios. Therefore, the first step in diagnosing any powertrain problem is to eliminate all of the aftermarket electrical equipment from the vehicle. After this is done, if the problem still exists, diagnose the problem in the normal manner.

Engine Controls Information

The driveability and emissions information describes the function and operation of the control module. The emphasis is placed on the diagnosis and repair of problems related to the system.

Engine Components, Wiring Diagrams, and Diagnostic Trouble Code (DTC) tables

  1. The Component Locations
  2. The Wiring Diagrams
  3. The Control Module Terminal End View and Terminal Definitions
  4. The Diagnostic System Check - Vehicle
  5. The Diagnostic Trouble Code (DTC) tables

The Component System includes the following items

  1. The component and circuit description
  2. The On-vehicle service for each subsystem
  3. The Functional checks with the diagnostic tables
  4. How To Use Electrical Systems Diagnostic Information

The DTCs also contain the diagnostic support information containing the circuit or the system information, and helpful diagnostic information.

Wiring Harness Service

The control module harness electrically connects the control module to the various solenoids, switches, and sensors in the vehicle engine compartment and passenger compartment.

Replace the wire harnesses with the proper part number replacement. When splicing signal wires into a harness, use the wiring that has high temperature insulation.

Consider the low amperage and voltage levels utilized in the powertrain control systems. Make the best possible bond at all splices. Use rosin-core solder in these areas.

Molded-on connectors require complete replacement of the connector. Splice a new connector into the harness. Replacement connectors and terminals are listed in Group 8.965 in the Standard Parts Catalog.

For wiring repair, refer to Wiring Repairs in Wiring Systems.

Connectors and Terminals

In order to prevent shorting between opposite terminals, use care when probing a connector and when replacing terminals. Damage to the components could result.

Always use jumper wires between connectors for circuit checking.

Never probe through the Weather-Pack seals.

The J 35616 Connector Test Adapter Kit, or the equivalent, contains an assortment of flexible connectors used in order to probe the terminals during the diagnosis. The fuse remover and the BT-8616 Test Tool, or the equivalent, is used for removing a fuse and to adapt the fuse holder to a meter for diagnosis.

Open circuits are often difficult to locate by sight because oxidation or terminal misalignment are hidden by the connectors. Merely wiggling a connector on a sensor or in the wiring harness may temporarily correct the open circuit. Oxidized or loose connections may cause intermittent problems.

Be certain the type of connector and terminal before making any connector or terminal repair. Weather-Pack and Com-Pack III terminals look similar, but are serviced differently.

Scheme 28

Scheme 28: Accelerator Pedal Position (APP) System Description
Scheme 28: Accelerator Pedal Position (APP) System Description

The accelerator pedal position (APP) system along with the vehicle electronics and components is used to calculate and control the amount of acceleration and deceleration via fuel injector control. This eliminates the need for a mechanical cable attachment from the accelerator pedal to a throttle body.

The APP system includes, but is not limited to, the following components

  1. The accelerator pedal position (APP) sensor assembly
  2. The engine control module (ECM)

Accelerator Pedal Position (APP) Sensor

The accelerator pedal position (APP) sensor is mounted on the accelerator pedal control assembly. The sensor is made up of 3 individual sensors within one housing. Three separate signal, low reference, and 5-volt reference circuits are used in order to interface the accelerator pedal sensor assembly with the ECM. Each sensor has a unique functionality to determine pedal position. The ECM uses the APP sensor to determine the amount of acceleration or deceleration desired by the person driving the vehicle. The APP sensor 1 voltage should increase as the accelerator pedal is depressed, from below 1.0 volt at 0 pedal travel to above 2 volts at 100 percent pedal travel. APP sensor 2 voltage should decrease from above 4 volts at 0 pedal travel to below 3.0 volts at 100 percent pedal travel. APP sensor 3 voltage should decrease from above 3.8 volts at 0 percent pedal travel to below 3.3 volts at 100 percent pedal travel.

Fuel System Description

CalloutComponent Name
1Fuel Rail
2Fuel Pressure Sensor
3Fuel Injectors
4Fuel Return Junction Block
5Fuel Tank
6Fuel Injection Control Module
7Fuel Filter
8First Start Fuel Bleeder Valve
9Fuel Injection Pump

The fuel tank (5) stores the fuel supply. A mechanical fuel injection pump (10), located below the engine intake, draws fuel through the fuel injector control module (6) and the fuel filter (7). The fuel is used as a coolant for the fuel injector control module. The fuel pump output is controlled by the ECM, and provides fuel at the pressure needed by the fuel injectors (3). The fuel injectors supply fuel directly to the combustion chambers of the engine. A separate pipe returns unused fuel through a fuel cooler (4) and to the fuel tank.

Scheme 29

Scheme 29: Fuel Tanks
Scheme 29: Fuel Tanks

The fuel tanks store the fuel supply. The primary fuel tank (2) is located on the left side of the vehicle. On vehicles that are equipped with dual fuel tanks, the auxiliary fuel tank is located in the rear of the vehicle. The fuel tanks are each held in place by 2 metal straps that attach to the frame. The fuel tanks are molded from high density polyethylene.

Scheme 30

Scheme 30: Fuel Filler Cap
Scheme 30: Fuel Filler Cap

The fuel filler cap has a torque-limiting device that prevents the cap from being over tightened. To install, turn the cap clockwise until you hear audible clicks. This indicates that the cap is fully seated.

Scheme 31

Scheme 31: Fuel Sender Assembly
Scheme 31: Fuel Sender Assembly

The fuel sender consists of the following major components

  1. The fuel level sensor (1)
  2. The fuel strainer (2)

Scheme 32

Scheme 32
Scheme 32

The auxiliary fuel sender on vehicles equipped with dual fuel tanks consists of the following major components

  1. The fuel level sensor (1)
  2. The fuel strainer (2)

Fuel Level Sensor

The fuel level sensor consists of a float, a wire float arm, and a ceramic resistor card. The position of the float arm indicates the fuel level. The fuel level sensor contains a variable resistor which changes resistance in correspondence with the amount of fuel in the fuel tank. The engine control module (ECM) sends the fuel level information via the class 2 circuit to the instrument panel cluster (IPC). This information is used for the instrument panel (I/P) fuel gage and the low fuel warning indicator, if applicable. The ECM also monitors the fuel level input for various diagnostics.

Fuel Strainer

The fuel strainer attaches to the lower end of the fuel sender. The fuel strainer is made of woven plastic. The functions of the fuel strainer are to filter contaminants and to wick fuel. The fuel strainer is self-cleaning and normally requires no maintenance. Fuel stoppage at this point indicates that the fuel tank contains an abnormal amount of sediment.

Scheme 33

Scheme 33: Fuel Pump
Scheme 33: Fuel Pump

On vehicles equipped with dual fuel tanks, an electric fuel pump is located on the left frame rail. This fuel pump is powered by the fuel pump relay that is controlled by the engine control module (ECM). Fuel is transferred from the auxiliary fuel tank to the primary fuel tank in order to ensure all of the usable fuel volume is available to the fuel injection pump.

Scheme 34

Scheme 34: Fuel Injection Pump
Scheme 34: Fuel Injection Pump

The fuel injection pump is a mechanical high pressure pump. The fuel injection pump is located below the intake manifold. Fuel is pumped to the fuel rails at a specified pressure. Fuel pressure is regulated by a valve on the inlet of the fuel pump, controlled by the engine control module (ECM). Excess fuel from the fuel injection pump returns to the fuel tank through the fuel return pipe and a fuel cooler.

Scheme 35

Scheme 35: Fuel Filter
Scheme 35: Fuel Filter

The fuel filter is located on the rocker cover. The paper filter element traps particles in the fuel that may damage the fuel injection system.

Fuel Feed and Return Pipes

The fuel feed pipe carries fuel from the fuel tank to the fuel injector control module. The fuel return pipe carries fuel from the fuel rail assemblies back to the fuel tank. The fuel pipes consist of 2 sections

  1. The rear fuel pipe assemblies are located from the top of the fuel tank to the chassis fuel pipes. The rear fuel pipes are constructed of steel with sections of rubber hose covered with braiding.
  2. The chassis fuel pipes are located under the vehicle and connect the rear fuel pipes to the fuel rail pipes. These pipes are constructed of steel with sections of rubber hose covered with braiding.

Quick-Connect Fittings

Quick-connect fittings provide a simplified means of installing and connecting fuel system components. The fittings consist of a unique female connector and a compatible male pipe end. O-rings, located inside the female connector, provide the fuel seal. Integral locking tabs inside the female connector hold the fittings together.

Fuel Pipe O-Rings

O-rings seal the connections in the fuel system. Fuel system O-ring seals are made of special material. Service the O-ring seals with the correct service part.

Scheme 36

Scheme 36: Fuel Rail Assemblies
Scheme 36: Fuel Rail Assemblies

The left and right fuel rail assemblies attach to the cylinder heads. The fuel rail assemblies distribute pressurized fuel to the fuel injectors through the fuel lines.

The fuel rail assemblies consists of the following components

  1. The fuel rail pressure sensor in the right fuel rail
  2. The fuel pressure relief valve in the left fuel rail

The fuel rail pressure sensor gives the engine control module (ECM) an indication of fuel pressure. The ECM uses this information to regulate fuel pressure, by commanding the fuel pressure regulator open or closed on the inlet of the fuel injection pump.

The fuel pressure relief valve opens only to prevent excessive pressure in the event of a malfunction. Fuel from the fuel pressure relief valve is returned to the fuel tank.

Scheme 37

Scheme 37: Fuel Injectors and Return Lines
Scheme 37: Fuel Injectors and Return Lines

Scheme 38

Scheme 38
Scheme 38

A fuel injector is a solenoid device, controlled by the fuel injection control module (FICM), that meters pressurized fuel to a single engine cylinder. The engine control module (ECM) energizes the low-impedance injector solenoid to open a normally closed valve. Fuel pressure is released from above the fuel injector pintle, and is returned to the fuel tank through the fuel return lines. The difference in fuel pressure above and below the pintle causes the pintle to open. Fuel from the fuel injector tip is sprayed directly into the combustion chamber on the compression stroke of the engine.

Scheme 39

Scheme 39: Fuel System Cooler
Scheme 39: Fuel System Cooler

The fuel system cooler (1) is located in front of the primary fuel tank. The fuel system cooler cools the fuel before it is returned to the fuel tank.

High Idle System

The diesel engine has a high idle system to improve the warm-up time of the engine in cold weather conditions. This system allows the engine control module (ECM) to increase the idle speed above the normal calibrated value. The ECM increases the idle speed using the following adjustments

  1. The fuel injection timing is changed.
  2. The fuel injection quantity is changed.
  3. The turbocharger vane position is commanded closed. the vane position will be farther closed than any other normal operating condition.

The instrument panel will indicate the high idle system is active one of two ways

  1. The driver information center (DIC) will indicate an active high idle system on light duty trucks.
  2. An indicator lamp will flash on medium duty trucks.

High Idle Speed Enable and Disable

To enable or disable the high idle system perform the following procedure

  1. Turn the ignition ON, with the engine OFF.
  2. Depress the accelerator pedal to the floor and hold down.
  3. While the accelerator pedal is depressed, depress the brake pedal 3 times in less than 8 seconds.
  4. Release the accelerator pedal.
  5. Start the engine.

When the procedure is followed the engine idle speed will slowly increased to the calibrated high idle speed. This is 1200 RPM for light duty, and 1500 RPM for medium duty trucks.

The idle speed will return to normal if any of the following conditions occur

  1. There is brake, clutch, or throttle input from the driver.
  2. The automatic transmission is shifted out of Park or Neutral.
  3. The air temperature is more than 0°C (32°F).
  4. The engine coolant temperature (ECT) is more than 68°C (154°F)
  5. The vehicle speed exceeds 0 km/h (0 mph).

The high idle system will reactivate automatically when the following conditions occur

  1. The engine has been idling for more than 30 seconds.
  2. The transmission is placed in Park or Neutral.
  3. the vehicle speed is 0 km/h (0 mph).
  4. The ambient air temperature is less than 0°C (32°F).
  5. The ECT is less than 68°C (154°F)
  6. The brake, clutch and throttle pedals are not depressed.

Glow Plug System Description

In the diesel engine, air alone is compressed in the cylinder. Then, after the air has been compressed, a charge of fuel is sprayed into the cylinder and ignition occurs, due to the heat of compression. Eight glow plugs are used as an aid to starting.

Control of the instant start system (ISS) glow plugs is accomplished by an electronic glow plug control unit and 4.7 volt glow plugs, requiring 2 seconds to heat up to 1,000°C (1,832°F). The temperature and the power consumption is controlled between the engine control module (ECM) and the controller within a wide range to suit the engine's pre-heating requirements. Each glow plug is energized individually. This capability yields more optimum heat times for the glow plugs, thus pre-glow times can be kept to a minimum for short wait to crank times and maximum glow plug durability. A DTC will set if there is a glow plug system fault.

A normal functioning system operates as follows

  1. Turn the ignition ON with the engine OFF, and at room temperature.
  2. The glow plugs turn ON and heat up in 2 seconds and then are pulse-width modulated (PWM) for another 2 seconds.
  3. The glow plug wait lamp is ON for 1 second.
  4. If the engine is cranked during or after the above sequence, the glow plugs may cycle ON and OFF after the ignition switch is returned from the start position, whether the engine starts or not. The engine does not have to be running to terminate the glow plug cycling.

The glow plug initial ON time will vary based on the system voltage and temperature. Lower temperatures cause longer ON times.

The ECM provides glow plug operation after starting a cold engine. This post-start operation is initiated when the ignition switch is returned to Run, from the Start position. This function helps clean up excessive white smoke and/or poor idle quality after starting.

Glow Plugs

The glow plugs are 4.7 volt heaters in each of the cylinders that turn ON, then pulse-width modulated when the ignition switch is turned to the RUN position prior to starting the engine. They remain pulsing a short time after starting, then they are turned OFF.

A Wait to Start lamp on the instrument panel provides information on engine starting conditions. The Wait to Start lamp will not illuminate during post-start glow plug operation.

Glow Plug/Controller

The glow plug controller is a solid state device which operates the glow plugs. The glow plug controller is connected to the following circuits

  1. The fuel heater ignition 1 voltage circuit
  2. The battery voltage circuit
  3. The CAN communication circuit located between the engine control module (ECM) and the glow plug controller
  4. The engine ground circuit
  5. The glow plug supply voltage circuits located between the glow plug controller and the glow plugs.

The glow plug diagnostic circuits are directly monitored individually by using a separate transistor to control current to each glow plug. Individual diagnosis is thus possible for every glow plug.

Exhaust Gas Recirculation (EGR) System Description

The Exhaust Gas Recirculation (EGR) System is used to reduce the amount of nitrogen oxide (NOx) emission levels caused by high combustion temperatures. At temperatures above 1 371°C (2,500°F), oxygen and nitrogen combine to form oxides of nitrogen (NOx). Introducing small amounts of exhaust gas back into the combustion chamber displaces the amount of oxygen entering the engine. With less oxygen in the air/fuel mixture, the combustion pressures are reduced, and as a result, combustion temperatures are decreased, restricting the formation of NOx.

The EGR valve motor is a direct current (DC) stepper motor utilizing a worm gear that extends from the motor to push on the EGR valve stem. The worm gear is not attached to the valve stem, and can only force the valve open. A return spring is used to force the valve closed.

The mass air flow (MAF) sensor signal is used by the engine control module (ECM) to detect the proper amount of EGR flow. One EGR flow test is performed per ignition cycle. The ECM will close the EGR valve for 5 seconds, then open the EGR valve to 100 percent for 5 seconds. The ECM will then calculate the MAF difference and determine if the proper EGR flow has been detected.

Scheme 40

Scheme 40: Exhaust Gas Recirculation (EGR) System Operation
Scheme 40: Exhaust Gas Recirculation (EGR) System Operation
CalloutComponent Name
1EGR Valve Position Sensor
2EGR Valve Worm Gear
3EGR Valve Return Spring
4EGR Valve Head
5EGR Valve Stem
6EGR Valve Motor

The exhaust gas recirculation (EGR) valve is controlled by the engine control module (ECM) through the EGR motor high control and EGR motor low control circuits. The ECM supplies voltage that is near ignition voltage to the high and low control circuits at all times. This voltage is used by the ECM as a reference voltage during non EGR operation in order to detect circuit failures. The ECM will pulse width modulate (PWM) the low control circuit to ground and an increase in amperage on the high control circuit can be observed with a DMM when the EGR valve is commanded open. A lower pulse width will increase the open position of the valve. In order to close the EGR valve, the ECM will PWM the high control circuit to ground.

When the ignition is turned ON, the ECM will drive the EGR motor worm gear out with just enough force to touch the EGR valve stem. The ECM will do this 3 times in quick succession. This action determines the minimum closed position of the valve and only happens once per ignition cycle. If the valve is prevented from closing all of the way after the minimum closed position is learned, the scan tool EGR Position parameter will not reflect this position until the next ignition cycle. The EGR motor worm gear is not connected to the EGR valve stem and can only push the valve open. The valve is returned to the closed position by a return spring.

The ECM uses the EGR position sensor to determine the position of the EGR valve. The ECM sends a reference voltage through the 5-volt reference circuit to the EGR position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the EGR valve position, is sent from the sensor to the ECM through the EGR position sensor signal circuit.

EGR Valve Control Enabling Conditions.

Exhaust gas recirculation (EGR) valve control will only be enabled during idle and cruising conditions while the following conditions are met

  1. The intake air temperature (IAT) is more than 5.25°C (41.5°F). EGR valve control will remain enabled until the IAT is less than 0°C (32°F) and will not enable again until the IAT is more than 5.25°C (41.5°F).
  2. The engine coolant temperature (ECT) is between 60-96.75°C (140-206.15°F). EGR valve control will remain enabled until the ECT is less than 57°C (134.6°F) or more than 99.75°C (211.55°F) and will not enable again until the ECT is between 60-96.75°C (140-206.15°F).
  3. The barometric pressure (BARO) is more than 74 kPa. EGR valve control will remain enabled until the BARO is less than 72 kPa and will not enable again until 74 kPa.

Air Intake System Description

The air intake system is used to direct cool air from the exterior of the engine compartment to the intake manifold. An air cleaner is incorporated into the system to keep dirt from entering the engine. The system also has a turbocharger to increase power, improve driveability and reduce emissions.

Scheme 41

Scheme 41: Air Cleaner Restriction Indicator
Scheme 41: Air Cleaner Restriction Indicator
CalloutComponent Name
1Reset Button
2Window

The air cleaner restriction indicator is located on the air cleaner housing.

If the area inside of the clear section is green, no air filter service is required. If the area inside the clear section is orange and Change Air Filter appears, replace the air filter.

Scheme 42

Scheme 42: Turbocharger Description and Operation
Scheme 42: Turbocharger Description and Operation
CalloutComponent Name
1Turbocharger Vane Position Sensor
2Turbocharger Vane Position Control Solenoid Valve
3Turbocharger Vane Position Unison Ring
4Turbine
5Turbocharger Vanes
6Hydraulic Piston
7Cam

The turbocharger increases engine power by pumping compressed air into the combustion chambers, allowing a greater quantity of fuel to combust at the optimal air/fuel ratio. In a conventional turbo, the turbine (4) spins as exhaust gas flows out of the engine and over the turbine blades. This spins the compressor wheel at the other end of the turbine shaft, pumping more air into the intake system.

The turbocharger for this system has vane position control by the engine control module (ECM). The vanes (5) can be opened and closed to vary the amount of boost pressure. Thus, the boost pressure can be controlled independent of engine speed. There are 9 controllable vanes in this turbocharger. The vanes mount to a unison ring (3) that can be rotated to change the vane angle. When the engine is not under load, the vanes are open to minimize boost and exhaust back pressure. To increase boost when the engine load requires it, the vanes are commanded closed. The ECM will vary the boost dependent upon the load requirements of the engine.

The turbocharger vanes are normally open when the engine is not under load. However, the ECM will often close the turbocharger vanes to create back pressure to drive exhaust gas through the exhaust gas recirculation (EGR) valve as required. At extreme cold temperatures, the ECM may close the vanes at low load conditions in order to accelerate engine coolant heating. The ECM may also close the turbocharger vanes under exhaust braking conditions.

The turbocharger control system utilizes the following components

Turbocharger Vane Position Control Solenoid Valve

The vane position control solenoid valve (2) works in conjunction with oil pressure to control the turbocharger vanes. The solenoid valve uses 2 circuits; a control circuit and a low reference circuit. The engine control module (ECM) uses a pulse width modulation on the HI control circuit to control the solenoid valve. The ECM will control the solenoid valve to allow the engine oil pressure (EOP) to move a piston (6). This piston rotates the unison ring, thus controlling the engine boost dependent upon engine load.

Turbocharger Vane Position Sensor

The vane position sensor (1) uses 3 circuits: a 5-volt reference circuit, a low reference circuit, and a signal circuit. The engine control module (ECM) provides the sensor with 5 volts on the 5-volt reference circuit and a ground on the low reference circuit. Movement of the sensor from the open vane position to the closed vane position provides the ECM with a signal voltage through the position sensor signal circuit that ranges from 1 volt with the turbocharger vanes open to 3.5 volts with the turbocharger vanes completely closed.

Engine Control Module (ECM)

The engine control module (ECM) controls all turbocharger control functions. The ECM monitors information from various sensor inputs that include the following

  1. The accelerator pedal position (APP) sensor
  2. The engine coolant temperature (ECT) sensor
  3. The mass airflow (MAF) sensor
  4. The intake air temperature (IAT) sensor
  5. The vehicle speed sensor (VSS)
  6. The transmission gear position or range information sensors
  7. The boost pressure sensor

Special Tools

Special Tools Illustration Tool Number/Description EN 47589 Fuel Pressure Test Adapter J 23738-A MityVac J 28428-E High Intensity Black Light Kit J 28428-E 12-v Unpowered Test Lamp J 34730-405 Injector Test Lamp J 35616-A Connector Test Adapter Kit J 38641-B Diesel Fuel Quality Tester J 43178 Fuel Line Disconnect Tool J 44402 Fuel Tank Sending Unit Wrench J 43244 Relay Puller Pliers J 44581 Fuel Line Disconnect Tool J 44638 Vacuum Gage J 45004 Fuel Tank Drain Hose J 45722 Fuel Sender Lock Ring Wrench J 45873-E Fuel Return Volume Test Kit J 46091 Charge Air Cooler Tester J 46594 Fuel Injector Remover

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Scheme 43: Special Tools
Scheme 43: Special Tools

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