Engine Controls - Removal & Installation: Other GMC Yukon Denali

COMPUTERIZED ENGINE CONTROLS

Note. All vehicles are equipped with either a Powertrain Control Module (PCM) or Vehicle Control Module (VCM) for engine control. Unless specifically stated, references to PCM also apply to VCM equipped vehicles. Some vehicles equipped with an electronically-controlled transmission also use a Transmission Control Module (TCM) for transmission control.

ELECTRICALLY ERASABLE PROGRAMMABLE READ-ONLY MEMORY

The Electrically Erasable Programmable Read-Only Memory (EEPROM) is a permanent memory that is part of PCM. EEPROM cannot be replaced. EEPROM contains program and calibration information that PCM uses to control powertrain. If PCM is replaced, ensure NEW PCM software/calibration is correct and most recent version for vehicle. EEPROM must be programmed when NEW PCM is installed. Program EEPROM using latest software for that specific vehicle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION.

POWERTRAIN CONTROL MODULE

Note. Before replacing PCM, carefully inspect all wiring and control components. Failure to test for short circuits may result in repeated PCM failure due to shorts and Quad-Driver failure. To prevent internal damage to PCM, ensure ignition switch is in OFF position when connecting or disconnecting PCM harness connectors or any electrical components.

Note. On 4.3L, 5.0L, 5.7L and 7.4L, new PCM does not come equipped with knock sensor module. When replacing defective PCM, remove knock sensor module from defective PCM and reinstall into new PCM.

Ensure ignition is off. Disconnect negative battery cable. Disconnect harness connectors from PCM. Remove PCM from vehicle. On 4.3L, 5.0L, 5.7L and 7.4L, remove access cover and remove knock sensor module from PCM.

Note. On all models except 1.6L and 2.0L, after installation of a NEW PCM, Malfunction Indicator Light (MIL) will remain illuminated until PCM is programmed.

On 4.3L, 5.0L, 5.7L and 7.4L, install knock sensor module in NEW PCM. Install access cover. On all models, install PCM into vehicle. Connect harness connectors to PCM. Reconnect negative battery cable. If NEW PCM has been installed, PCM MUST be programmed. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION.

POWERTRAIN CONTROL MODULE (PCM) PROGRAMMING (6.5L DIESEL)

1. If PCM was replaced, the PCM must be programmed. If PCM is not programmed, a Diagnostic Trouble Code (DTC) will be set in the PCM.
2. Ensure battery is fully charged. Ensure cable at Data Link Connector (DLC) and power supply for scan tool are properly connected. Turn ignition on. Perform EEPROM programming using the Techline equipment manufacturer's instructions and latest software applicable for the vehicle model.
3. Perform password learn procedure for anti-theft system. See PASSWORD LEARN PROCEDURE FOR ANTI-THEFT SYSTEM (6.5L DIESEL). Once PCM is programmed, if only the PCM was replaced, go to next step. If the crankshaft position sensor, engine or PCM with fuel injection pump were replaced, perform TDC offset learn procedure. See TDC OFFSET LEARN PROCEDURE (6.5L DIESEL). NOTE: If PCM programming fails, ensure all electrical connections on PCM are okay. Check Techline for latest software. If EEPROM programming still fails, replace PCM.
4. Start engine and warm engine until engine coolant temperature is at least 170°F (77°C). This will allow TDC offset to be programmed into the PCM if necessary. The PCM has the ability to determine the amount of offset required to bring the engine to TDC. PCM uses the TDC to determine proper fuel injection pump timing. If TDC offset is not programmed, a Diagnostic Trouble Code (DTC) P1214 will be set in the PCM.

TDC OFFSET LEARN PROCEDURE (6.5L DIESEL)

1. Procedure must be performed if any of the following have been done or exists: If sent here from Diagnostic Trouble Code (DTC) P1214. Engine has been replaced. Crankshaft position sensor or engine front cover has been replaced. Powertrain Control Module (PCM) and fuel injection pump have been replaced. NOTE: DO NOT perform procedure unless sent here from DTC P1214 or one of the components listed above have been replaced.
2. The PCM has the ability to determine amount of offset required to bring the engine to TDC when TDC offset is not present or has been cleared. This procedure must be performed to allow PCM to be updated with the correct TDC offset for vehicle application.
3. Install scan tool on Data Link Connector (DLC). Start engine and warm engine until engine coolant temperature is at least 170°F (77°C). Using scan tool, clear DTCs from PCM. Turn ignition on with engine off. Fully depress and hold throttle at full throttle for at least 45 seconds.
4. Turn ignition off for 30 seconds. Start engine. Verify scan tool indicates TDC offset has been cleared to zero. If TDC offset has been cleared to zero, go to next step. If TDC offset has not been cleared to zero, repeat step 3) until TDC offset has been cleared to zero.
5. With engine running, use scan tool to verify engine coolant temperature is greater than 170°F (77°C). It may be necessary to drive vehicle to obtain correct engine coolant temperature if engine coolant temperature is less than specified.
6. As soon at engine coolant temperature is greater than 170°F (77°C) and engine speed is less than 1500 RPM, the PCM automatically learns a NEW TDC offset. The NEW TDC offset will overwrite the previous TDC offset. Using scan tool, note NEW TDC offset. TDC offset should be -.25 to -.75.
7. Shut engine off. If TDC offset is not within specification, go to next step. If TDC offset is within specification, TDC offset learn procedure is complete.
8. Using Flange Nut Wrench (J41089), loosen fuel injection pump retaining nuts. Fuel injection pump must be rotated to change TDC offset. Rotating fuel injection pump.039" (1.00 mm) will change TDC offset about 2 degrees. Rotating fuel injection pump toward driver's side of vehicle will produce a positive (+) number and rotating fuel injection pump toward passenger's side of vehicle will produce a negative (-) number.
9. Using Fuel Injection Pump Wrench (J 29872-A), slightly rotate fuel injection pump. Tighten fuel injection pump retaining nuts.
10. Repeat step 3) through 9) until TDC offset is within specification. If proper TDC offset cannot be obtained, check the following: Ensure engine coolant temperature is greater than 170°F (77°C). Electric connectors at PCM are properly installed. Electric connectors at injection timing stepper motor on side of fuel injection pump is correctly installed. Ensure latest Techline software was used. Check for proper base installation of fuel injection pump. The electric engine shutoff solenoid on top of fuel injection pump should be approximately straight up and down. Fuel injection pump may be defective, although manufacturer states this is highly unlikely.

CRANKSHAFT POSITION SENSOR

Note. Some models require CRANKSHAFT POSITION (CKP) SENSOR VARIATION LEARN PROCEDURE to be performed when CKP sensor is removed or replaced. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION.

KNOCK SENSOR MODULE

Note. On 4.3L, 5.0L, 5.7L and 7.4L, Knock Sensor (KS) module is a separate module attached to PCM. On all other models, KS module is an integral part of PCM.

FUEL SYSTEM PRESSURE RELIEF

Fuel system is under pressure. Pressure must be relieved prior to servicing fuel system. Fuel pressure may be relieved by using one of the following methods

1. On 1.6L and 2.0L, loosen fuel filler cap to release fuel tank pressure (do not tighten at this time). Remove fuel pump relay. Start and run engine until it stalls. Crank starter for 3 seconds to remove remaining fuel from fuel lines. Turn ignition off. Reinstall fuel pump relay. Disconnect negative battery cable to avoid possible fuel discharge in accidental attempt to start engine.
2. On all models except 1.6L and 2.0L, disconnect negative battery cable. Loosen fuel filler cap. Install Fuel Pressure Gauge (J-34730-1A) on fuel pressure connector of fuel rail. Wrap shop towel around pressure connection when installing fuel pressure gauge to absorb fuel leakage. Install gauge bleed hose in container. Open bleed valve to bleed fuel pressure.

FUEL PUMP

Note. When installing fuel sending unit assembly, DO NOT fold or twist strainer. This will restrict fuel flow.

Note. 5.0L, 5.7L and 7.4L models are also equipped with a balance pump. Balance pump is located on right side frame rail.

OXYGEN SENSOR

Note. Oxygen sensor is mounted in exhaust pipe, below exhaust manifold and is equipped with a permanent pigtail which must remain intact when removing sensor.

1. Ensure oxygen sensor is free of contaminants. DO NOT use cleaning solvents of any type. Oxygen sensor may be difficult to remove when engine temperature is less than 120°F (48°C). Excessive removal force may damage threads in exhaust manifold or pipe.
2. Disconnect negative battery cable. Disconnect harness connector from oxygen sensor. Carefully remove oxygen sensor from exhaust pipe.

1. Whenever oxygen sensor is removed, coat threads with anti-seize compound before reinstallation. New oxygen sensors already have this compound applied to threads.
2. Install oxygen sensor in exhaust pipe. Tighten oxygen sensor to specification. See «TORQUE SPECIFICATIONS»(ref-4644-S02362081762000071100000) . Reconnect harness connector to oxygen sensor. Reconnect negative battery cable.

THROTTLE BODY (CSI)

THROTTLE BODY (SFI)

Note. When installing fuel sending unit assembly, DO NOT fold or twist strainer. This will restrict fuel flow.

Note. Diesel models are also equipped with a lift pump. Lift pump is located on right-side frame rail.

1. Fuel pump is located in fuel tank and is integral with fuel sending unit assembly. Fuel pump must be replaced with fuel sending unit as an assembly. Remove fuel filler cap. Disconnect negative battery cable. Drain fuel tank.
2. Raise and support vehicle. Disconnect fuel lines and electrical connections at fuel tank. Remove fuel tank. Using Cam Lock Remover (J-36608), turn cam lock counterclockwise. Lift fuel sending unit assembly from fuel tank. To install, reverse removal procedure using NEW "O" ring and gasket.

1. Disconnect negative battery cable. Remove intake manifold. Install Protective Covers (J-29664-1) in intake ports. Disconnect fuel injection lines. Disconnect fuel inlet line, harness connectors and hoses, and fuel return line at injection pump. Cap all openings.
2. Remove oil filler tube and grommet for oil filler tube. Remove injection pump timing gear cover. Scribe or paint alignment mark on front cover and injection pump flange. Manually rotate engine to position cylinder No. 1 at TDC on compression stroke. Remove injection pump-to-drive gear retaining bolts. Remove injection pump mounting nuts. Remove injection pump and gasket. see scheme 45

1. Install NEW injection pump gasket. Align locating pin on injection pump hub with slot in injection pump driven gear. At the same time, align injection pump timing marks. Ensure cylinder No. 1 is set at TDC.
2. Attach injection pump to front cover. Ensure alignment marks made during removal are aligned. Tighten injection pump mounting nuts. Attach pump to drive gear and tighten bolts to specification. See «TORQUE SPECIFICATIONS»(ref-4644-S02362081762000071100000) . To complete installation, reverse removal procedure. Check injection pump timing. See appropriate ON-VEHICLE ADJUSTMENTS article.

Scheme 31

Disconnect negative battery cable. Disconnect fuel line clip. Remove fuel return line. Remove fuel injection line. Cap all openings. Using Injector Socket (J-29873), remove injector nozzle(s). Place socket on 1 3/16" (30 mm) hex flats of injector body to prevent damaging injector nozzle.

Remove caps from injector nozzles and fuel lines. Install injector nozzle(s). Install fuel injection line. Install fuel return line and fuel line clip. Reconnect negative battery cable. Start engine and check for leaks.

PURGING WATER FROM FUEL SYSTEM

1. Disconnect negative battery cable. Remove fuel filler cap. Place hand operated pump into fuel filler neck and drain fuel from fuel tank. Reinstall fuel filler cap. Remove fuel tank and fuel sending unit assembly. Replace fuel tank if internally rusted. Replace fuel strainer (as necessary).
2. Remove fuel feed hose at fuel pump. Remove fuel return line at injection pump. Using low air pressure, blow out fuel lines toward rear of vehicle. Replace fuel lines if internally rusted. Remove ECM 1 fuse. Remove fuel manager/filter element.
3. Install fuel sending unit assembly and fuel tank. Install fuel feed hose to fuel pump. Fill fuel tank with diesel fuel until tank is 1/4 full. Install fuel filler cap. Reconnect negative battery cable. Crank engine for 15 seconds. Allow starter to cool down for one minute between cranking intervals. Use suitable container to collect fuel. Repeat procedure until clear fuel is pumped out.
4. Install NEW fuel filter element. Connect a hose from fuel injection pump return line to a closed metal container with 2 gallon capacity. Crank engine for 15 seconds. Allow starter to cool down for one minute between cranking intervals. Repeat procedure until clear fuel is observed at fuel return line.
5. Install fuse. Crack open each injection line at each nozzle. Crank engine for 15 seconds. Allow starter to cool down for one minute between cranking intervals. Repeat procedure until clear fuel is observed at each nozzle. Install injection line to nozzle fitting and tighten to specification. See «TORQUE SPECIFICATIONS»(ref-4644-S02362081762000071100000) .
6. Start engine and idle for 5 minutes. Ensure fuel return line is in metal container and container does not overflow. Turn ignition off. Remove hose from metal container. Install fuel return line to injection pump. Check for leaks.

WATER-IN-FUEL WARNING LIGHT

1. Fuel manager/filter should be drained every 5000 miles, or when WATER-IN-FUEL warning light illuminates. Diesel fuel can damage asphalt and painted surfaces. Always place drain pan under filter drain hose to collect fuel.
2. Stop vehicle and turn engine off. Apply parking brake. Open drain valve. Start and allow engine to idle for 2 minutes or until clear fuel is observed. Turn engine off and close drain valve.
3. If WATER-IN-FUEL warning light illuminates after fuel manager/filter is purged of water, remove water-in-fuel sensor and wipe tip of sensor clean. Reinstall water-in-fuel sensor. If WATER-IN-FUEL warning light remains illuminated, replace water-in-fuel sensor.

TURBOCHARGER

Note. Turbocharger overhaul information is not available from manufacturer. Replacement as a unit is recommended.

GASOLINE

TORQUE SPECIFICATIONS (GASOLINE)

DIESEL

TORQUE SPECIFICATIONS (DIESEL)