Hummer H1 1999 User Manual
hummer :: Hummer H1 V8-6.5L DSL Turbo (1999
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> Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Description and Operation
Engine Control Module: Description and Operation
POWERTRAIN CONTROL MODULE (PCM)
The PCM controls operation of all of the engine and transmission outputs. It is on a bracket attached to floor under the center console. The data linkconnector is the access point for the scan tool. The connector is under the instrument panel at the left side of the steering column. It is a multi-pinconnector with integral mounting bracket.
Signal inputs used by the PCM include:
- Coolant temperature
- Intake air temperature
- Boost/baro pressure
- Optical/fuel temperature sensor
- Crankshaft position sensor
- Accelerator pedal position sensors (APP)
- Cruise control
- A/C request
- Vehicle speed sensor
- Automatic transmission fluid pressure manual valve position switch
- Transmission input speed sensor
- Transfer case low range switch
- Transmission fluid temperature sensor
- Diagnostic request
> Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Glow Plug System > Glow Plug Relay > Component Information > Locations
Figure 3-59: Glow Plug Relay/Controller Location
> Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Glow Plug System > Glow Plug Relay > Component Information > Locations > Page 12
Glow Plug Relay: Service and Repair
GLOW PLUG RELAY/CONTROLLER REPLACEMENT
1. Disconnect battery ground cable.2. Remove console and engine cover.3. Disconnect power cable at relay/controller (Figure 3-59)
Figure 3-59: Glow Plug Relay/Controller Location
4. Disengage three connectors from glow plug controller.5. Remove retaining bolt and remove relay.6. Position relay/controller on bracket and install attaching hardware.7. Engage connectors in relay/controller.8. Connect power cable to relay/controller stud.9. Install engine cover and console.
10. Connect battery ground cable.
> Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Locations
Figure 3-58: Engine Temperature Sender
> Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Locations > Page 19
Coolant Temperature Sensor/Switch (For Computer): Diagrams
Figure 3-11: Coolant Temperature Sensor Circuit
> Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Locations > Page 20
Coolant Temperature Sensor/Switch (For Computer): Description and Operation
Figure 3-11: Coolant Temperature Sensor Circuit
Engine Coolant Temperature Sensor Test
The coolant temperature sensor is a thermistor that provides a temperature signal to the PCM (Figure 3-11). The signal is in the form of a voltage thatchanges according to sensor resistance. At low temperatures, resistance and voltage are both high. As temperature increases, resistance and voltage bothdecrease.
A sensor fault will cause the check engine light to illuminate and the torque converter clutch to apply early. If the sensor fails in a cold mode, it canproduce overrich operation and rough idle.
> Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Locations > Page 21
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
Figure 3-11: Coolant Temperature Sensor Circuit
Engine Coolant Temperature Sensor Test
The coolant temperature sensor is a thermistor that provides a temperature signal to the PCM (Figure 3-11). The signal is in the form of a voltage thatchanges according to sensor resistance. At low temperatures, resistance and voltage are both high. As temperature increases, resistance and voltage bothdecrease.
A sensor fault will cause the check engine light to illuminate and the torque converter clutch to apply early. If the sensor fails in a cold mode, it canproduce overrich operation and rough idle.
High Temperature-Low Resistance Test
- If indicated temperature is 266 F (130 C) or above, continue test.
- If indicated temperature agrees with ambient, sensor is OK.
3. Disconnect sensor and note temperature indicated on scan tool:
- If indicated temperature drops to -22 F (-30 C), sensor has failed and should be replaced.
- If indicated temperature does not drop, problem is with sensor wiring or connections.
Low Temperature-High Resistance Test
1. Connect scan tool and start engine.2. Note indicated temperature:
- If temperature is normal, problem is with sensor wires and connections.
1. Allow engine to cool down. Coolant should be at ambient temperature for test.2. Connect scan tool, start engine, and note sensor temperature.
- If temperature is at or above 266 F (130 C), continue with test. Disconnect sensor wires and note scan tool reading:
- If temperature now reads -22 F (-30 C), sensor has failed.
- If temperature is OK, problem is faulty sensor ground, reference wire shorted to ground, or PCM has fault.
> Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Locations > Page 22
Coolant Temperature Sensor/Switch (For Computer): Service and Repair
Figure 3-58: Engine Temperature Sender
ENGINE TEMPERATURE SENDER REPLACEMENT
1. Remove nut, lockwasher, lead, and sender from engine (Figure 3-58).2. Apply teflon sealant to sender threads, and install sender, lead, lockwasher, and nut on engine (Figure 3-58).
> Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Temperature Switch (Warning Indicator) > Component Information > Locations
Temperature Switch (Warning Indicator): Locations
The coolant temperature switch is in the water crossover.
> Sensors and Switches > Sensors and Switches - Instrument Panel > Fuel Gauge Sender > Component Information > Service and Repair
Fuel Gauge Sender: Service and Repair
Figure 3-34: Fuel Tank and Components
> Sensors and Switches > Sensors and Switches - Instrument Panel > Fuel Gauge Sender > Component Information > Service and Repair > Page 30
H1 V8-6.5L DSL Turbo (1999)
Figure 3-35: Auxiliary Fuel Tank Components
FUEL LEVEL TRANSMITTER AND TANK ACCESS PLATE SERVICE
> Sensors and Switches > Sensors and Switches - Instrument Panel > Fuel Gauge Sender > Component Information > Service and Repair > Page 31
H1 V8-6.5L DSL Turbo (1999)
Removal
1. Remove screws, lockwashers and fuel level transmitter from tank access plate (Figures 3-34 and 3-35).2. Remove locknuts, washers, access plate and gasket from tank.3. Remove access plate retainer and O-rings from tank. Discard O-rings.
Figure 3-36: Fuel Level Transmitter in Upright or Empty Position
Check fuel level transmitter operation as follows:
1. Hold transmitter in the upright or empty position (Figure 3-36).2. Using an ohmmeter, check resistance value at terminals. Resistance should be 268 20 Ohms.3. Hold transmitter in the inverted position simulating a full tank. Resistance should fall to 19.3 8 Ohms.
Installation
CAUTION: Do not overtighten access plate or transmitter fasteners. Gasket damage and improper sealing could result.
1. Thoroughly clean all gasket surfaces.2. Place new O-rings on access plate retainer studs and position access plate retainer in tank (Figures 3-34 and 3-35).3. Set gasket and access plate over studs and onto tank.4. Apply liquid teflon thread sealant to studs and loosely install washers and locknuts until no clearance exists between access plate, gasket and tank.5. Snug access plate locknuts in small increments and in a systematic circular pattern. Tighten locknuts until gasket bulges or until maximum torque
of 72 lb-in. is obtained.
6. Apply liquid teflon thread sealant to transmitter mounting screws.7. Secure gasket and transmitter to access plate using same method as indicated for access plate above.8. Cap all tank fittings and perform leak check. Apply leak check solution or soapy water around access plate and transmitter gaskets and fasteners.
Pump 3 p.s.i. of compressed air into tank and verify absence of leaks.
Quick Connect Fittings
Quick connect fittings are used at the main tank fuel tubes, auxiliary tank fuel tubes, and at the fuel tank selector valve.
Two types of fittings are used. One type is an all plastic push on style with removable retainer. The second style is a metal, one-piece fitting with aninternal tension clip to retain it. The plastic fitting retainer only requires a screwdriver and needle-nose pliers to remove. The metal fitting requires arelease tool, such as J 37088-A, in order to disconnect it.
The metal fittings are used at the main tank. The plastic, two-piece fittings are used at the auxiliary tank and fuel selector valve.
Metal Fittings
1. To disconnect, slide the release tool onto the line and into the fitting.2. Press the tool inward to unseat the internal clip and pull the line off the fuel tube.3. To reconnect, just push the fitting onto the line until it snaps or clicks into place.4. Pull on the fitting afterward to verify proper seating.
Plastic Fittings
1. To disconnect, raise the retainer tab with a small flat blade screwdriver and remove the retainer with needle-nose pliers.2. To reconnect, push the fitting onto the tube, insert the retainer through the fitting sides, and seat it firmly.3. Be sure the retainer seats behind the fuel tube flange.4. Pull on the fitting afterward to verify proper seating.
> Sensors and Switches > Sensors and Switches - Instrument Panel > Temperature Switch (Warning Indicator) > Component Information > Locations
Temperature Switch (Warning Indicator): Locations
The coolant temperature switch is in the water crossover.
> Sensors and Switches > Sensors and Switches - Instrument Panel > Water In Fuel Sensor > Component Information > Locations
Figure 3-41: Fuel Filter Components
> Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Accelerator Pedal Position Sensor > Component Information > Locations
Figure 3-7: Electronic Accelerator Pedal Components
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