Jeep Grand Cherokee

1993-1999 of release

Repair and operation of the car



Jeep Grand Cherokee
+ Cars of the Jeep Grand Cherokee brand
+ Settings and routine maintenance
+ Line six-cylinder engine
+ V8 engine
+ Procedures of the general and capital repairs of the engine
+ Cooling systems, heating and air conditioning
+ A power supply system and production of the fulfilled gases
+ System of electric equipment of the engine
- Systems of decrease in toxicity of the fulfilled gases and engine management
   General information
   System of multiposition injection of fuel (MPFI) and information sensors - the description
   Removal and installation of the electronic module of management (RSM)
   Description of the principle of action of system of self-diagnostics and procedure of reading of codes of malfunctions
   Information sensors
   System of the operated ventilation of a case (PCV)
   System of recirculation of the fulfilled gases (EGR)
   System of catching of vapors of fuel (EVAP)
   Catalytic converter
+ Manual box of gear shifting
+ Automatic transmission
+ Transfer case
+ Coupling and transmission line
+ Brake system
+ Suspension bracket and steering
+ Body
+ System of onboard electric equipment
+ Governing bodies and methods of operation



System of multiposition injection of fuel (MPFI) and information sensors - the description

The system of multiposition injection of fuel (MPFI) provides giving in the engine of the required quality of mix under any service conditions of the car. Injectors of system provide injection of fuel in each of inlet ports.

Brain of system of injection is the module of management of RSM. RSM is located in a forward corner of a motive compartment.

RSM receives and processes amplitude (on tension) signals from a set of various sensors, switches and relay. All entering signals will be transformed to the digital data which are read out by the module of management which is carrying out constant thin fine tuning of such major parameters of the engine on the basis of their analysis as an ignition advancing corner, duration of inclusion of current of the coil of ignition, duration of an impulse of inclusion of an injector and turns of idling of the engine for the purpose of minimization of pollution of the atmosphere products of combustion and receiving the maximum return from the engine. Besides, RSM controls operation of the fan of the cooling system, charging current of the generator and such components of system of decrease in toxicity of the fulfilled gases as electromagnets of EGR and a purge of a coal adsorber of the EVAP system. RSM is also capable to change the program according to working conditions.

Components of systems of decrease in toxicity of the fulfilled gases and engine management of models of 4.0 l (for models of 5.2 l the scheme is similar)

1 — D/V - Sensor switch
2 — VSS - Car speed sensor
3 — Ø/M - Electromagnet

4 — ASD Automatic shutdown of supply of fuel
5 — О/D - The raising transfer

RSM exercises constant control of a set of own entrance and output contours. In case of malfunction in the MPFI system information on her is fixed in memory of the module. It is not possible to make diagnostics of malfunctions of components of the MPFI system without existence of special expensive factory production of the tool and the reader of codes of malfunctions of DRB II (No. S-4805) or its equivalent, however in many cases it is possible to try to localize a source of the suspected refusal, having limited a search circle at least to a concrete contour. This work always begins with reading of codes of malfunctions, then visual survey of components of system for the purpose of check of a state and reliability of fastening of conducting and electric sockets is made. Most often weakening of fastening or a detachment of terminal connections of an electrical wiring or vacuum lines appears a cause of failure. Instructions on a conclusion of diagnostic information from memory of RSM "Check the engine for a control lamp" are provided in the Section Description of the Principle of Action of System of Self-diagnostics and Procedure of Reading of Codes of Malfunctions.

Information sensors

Enter number of a set of the sources transferring information to RSM:

  • Air conditioner clutch coupling relay
  • Relay of automatic shutdown of supply of fuel (ASD)
  • Sensor switch of stoplights
  • Sensor of position of the camshaft
  • Air temperature sensor
  • Cooler temperature sensor
  • Sensor of provision of a bent shaft
  • The sensor of absolute pressure in the pipeline (MAR)
  • Oxygen sensor
  • Sensor of provision of a butterfly valve (TPS)
  • Sensor switch of permission of start (provision of transmission)
  • Sensor of speed of the car (VSS)

Relay of a clutch coupling of the conditioner of air (K/V)

Operation of the relay of a clutch coupling To/in RSM operates. Control is exercised due to inclusion switching off of a contour of grounding of the relay. When RSM receives inquiry from the K/V control panel (a control system of climate), it gives the command for turning on of the motor of system of stabilization of turns of idling (IAC) for the purpose of the corresponding correction of turns. The relay of management of coupling To/in is located in distribution center of power supply near the battery.

Location of distribution center of power supply.

Relay of automatic shutdown of supply of fuel (ASD)

If lack of a signal of ignition (distributor) or from sensors of provision of a distributive or bent shaft takes place at turn of the ignition key in position of RUN (Movement), the ASD relay powers off the electric fuel pump, injectors of fuel, the coil of ignition and the warmed-up oxygen sensor. The disconnecting relay is located in distribution center of power supply near the battery.

Sensor of position of the camshaft

The sensor of position of the camshaft includes the semiconductor working at Hall's effect and gives the signal used for synchronization of work of power supply systems and ignition. The synchronizing signal is developed by the semiconductor at rotation of a ring of the sensor with the screen, located in the distributor.

Sensor of position of the camshaft of the engine of 4.0 l.

Air temperature sensor

The air temperature sensor installed in the inlet pipeline determines temperature of the entering air and transfers the relevant information to RSM. Information is used by the module at correction of air-fuel mix.

Location of the sensor of air temperature on the engine of 4.0 l.

Location of the sensor of air temperature on the engine of 5.2 l.

Cooler temperature sensor

The cooler temperature sensor which is screwed in in the thermostat case traces cooler temperature, sending the corresponding signals to RSM. These data together with information obtained from the sensor of air temperature are used by the module at correction of quality of gas mixture and turns of idling in the course of an engine warming up. The sensor also serves for turning on of the fan of an obduv of a radiator.

Location of the sensor of temperature of a cooler of the engine of 4.0 l.

Location of the sensor of temperature of a cooler of the engine of 5.2 l.

Sensor of provision of a bent shaft

The sensor of provision of a bent shaft fastens on a transmission dome. The sensor transfers information on the current provision of a bent shaft to RSM. As basic data the sensor uses cuts on a driving disk of the converter of rotation or a flywheel.

Location of the sensor of provision of a bent shaft of engines of 4.0 l equipped with AT.

Location of the sensor of provision of a bent shaft of engines of 4.0 l equipped with RKPP.

The sensor of absolute pressure in the pipeline (MAR)

The MAR sensor is located on a partition or a wall of a motive compartment. The sensor determines depression depth in the inlet pipeline through the vacuum line connected to the throttle case. The sensor transfers the taken readings to RSM together with data on barometric pressure in the form of tension changing on amplitude. In a compartment with information obtained from other sensors these data allow the module of management to define the required composition of gas mixture.

Location of the MAR sensor on the engine of 4.0 l.

Location of the MAR sensor on the engine of 5.2 l.

Various sensors switches

Sensors switches (such as switch of permission of start, the conditioner of air, control of speed and stoplights) supply RSM with information allowing it to make adjustments of functioning of the engine depending on a condition of various equipment (on/off). It is difficult to define indications of these sensors switches (high/low level of a signal) without diagnostic DRB II measuring instrument.

Oxygen sensor

The oxygen sensor located in a reception pipe of system of production of the fulfilled gases (right on V8 engines), gives amplitude (on tension) a signal depending on presence at system of production of the fulfilled oxygen gases. For acceleration of an exit of the sensor in an operating mode at warming up of the engine the sensor is equipped with the built-in electric heater. If the fulfilled gases contain considerable percent of oxygen (poor mix), the signal of the sensor has smaller amplitude; at the small content of oxygen (rich mix) amplitude of tension given by the sensor increases. Tracing percent of content in the fulfilled gases of oxygen and transferring it to an electric signal, the sensor works as the sensor switch of impoverishment enrichment of gas mixture. The signal from the sensor arrives on RSM which on the basis of its analysis increases or reduces impulse width (duration) of inclusion of injectors of fuel.

Location of the oxygen sensor.

Sensor of provision of a butterfly valve (TPS)

TPS located in the case of a throttle defines a corner of a deviation of a butterfly valve. Tension developed by the sensor increases or decreases depending on width of opening of the gate. Coming on RSM this signal to a compartment with the data obtained from other sensors allows the processor of the module to carry out correction of quality of mix depending on operating conditions of the engine, such as acceleration / деселерация, work on single turns or at completely open butterfly valve.

Location of TPS (engine of 5.2 l).

Sensor of distance (speed) of the car (VSS)

VSS located on lengthening of a case of transmission or the transfer case (depending on car equipment), serves for determination of speed of the movement of the car. The sensor develops eight impulses for each turn of a power shaft and transfers them to RSM. These signals are compared by the module to a signal of a closed position of a butterfly valve from TPS allow to distinguish conditions of closing of the gate when dumping turns of the engine and during the work of the last on single turns (on the standing still car) When dropping turns of the RSM engine exercises control of functioning of the IAC motor, trying to obtain the required signal from MAR; during the operation of the engine on single turns of RSM operates the IAC motor, supporting the desirable frequency of rotation of the engine.

Location of VSS.