Engine Control System & Engine Component Tests: Other — Jeep Cherokee II рестайлинг (1997-2001)

Engine Control System & Engine Component Tests: Other Jeep Cherokee II рестайлинг

POWERTRAIN CONTROL MODULE (PCM)

The PCM power and ground circuits may be checked by performing NTC-14: CHECKING PCM POWER & GROUND CIRCUITS in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article. Perform appropriate test. For PCM location, see PCM LOCATION table.

Application	Location
Cherokee	Left Front Fender, Near Radiator Support
Grand Cherokee	Right Rear Corner Of Engine Compartment
Wrangler	On Firewall, Near Blower Motor

PCM LOCATION

Camshaft Position (CMP) Sensor

See DTC P0340: NO CAM SIGNAL AT PCM in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Crankshaft Position (CKP) Sensor

See DTC P0320: NO CRANK REFERENCE SIGNAL AT PCM in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Engine Coolant Temperature (ECT) Sensor

See DTC P0117: ECT SENSOR VOLTAGE TOO LOW and DTC P0118: ECT SENSOR VOLTAGE TOO HIGH in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Heated Oxygen Sensor (HO2S)

See appropriate DTC TEST in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Intake Air Temperature (IAT) Sensor

See DTC P0112: IAT SENSOR VOLTAGE LOW and DTC P0113: IAT SENSOR VOLTAGE HIGH in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Manifold Absolute Pressure (MAP) Sensor

See DTC P0107: MAP SENSOR VOLTAGE TOO LOW and DTC P0108: MAP SENSOR VOLTAGE TOO HIGH in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Transmission Temperature (TRANS Temp) Sensor

See DTC P0712: TRANS TEMP SENSOR VOLTAGE TOO LOW and DTC P0713: TRANS TEMP SENSOR VOLTAGE TOO HIGH in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Throttle Position (TP) Sensor

See DTC P0122: THROTTLE POSITION SENSOR VOLTAGE LOW and DTC P0123: THROTTLE POSITION SENSOR VOLTAGE HIGH in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Vehicle Speed Sensor (VSS)

See DTC P0500: NO VEHICLE SPEED SENSOR SIGNAL in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Evaporative (EVAP) Purge Solenoid

See DTC P0443: EVAP PURGE SOLENOID CIRCUIT in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Leak Detection Pump (LDP) Solenoid

See DTC P1495: LEAK DETECTION PUMP SOLENOID CIRCUIT in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Speed Control (S/C) Solenoid

See DTC P1595: SPEED CONTROL SOLENOID CIRCUITS in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Transmission Governor Pressure Solenoid

See DTC P0748: GOVERNOR PRESSURE SOLENOID/TRANS RELAY CKTS in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Transmission 3-4 Solenoid

See DTC P0753: TRANS 3-4 SOLENOID/TRANS RELAY CKTS in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Leak Detection Pump (LDP) Switch

See DTC P1494: LEAK DETECTION PUMP SW OR MECH FAULT in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Park/Neutral (P/N) Switch

See DTC P1899: P/N SWITCH STUCK IN PARK OR IN GEAR in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Power Steering (PS) Switch

See DTC P0551: POWER STEERING SWITCH FAILURE in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Speed Control Switch

See DTC P1596: SPEED CONTROL SWITCH ALWAYS HIGH and DTC P1597: SPEED CONTROL SWITCH ALWAYS LOW in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

CCV System

This system is used on 2.5L and 4.0L engines. It performs same function as a conventional PCV system, but does not use a vacuum controlled valve. Ensure locations of fixed orifice fitting and air inlet fitting have not been exchanged. Fixed orifice fitting is Gray and is located at rear of valve cover. Air inlet fitting is Black and is located at front of valve cover.
Remove fixed orifice fitting from valve cover and leave tube attached. Start engine and let idle. A hissing noise should be heard from fitting orifice. Also, a strong vacuum should be felt with a finger placed at fitting inlet. If vacuum is not present, remove fitting. If vacuum is now present at tube, replace fitting. Do not attempt to clean fitting. If vacuum is not present at tube, go to next step.
Check tube for kinks or obstruction. Clean tube fitting at intake manifold, if necessary. A 1/4" drill may be used (by hand) to dislodge any solid particles. Reinstall fixed orifice fitting and tube. Disconnect air inlet fitting and hose from front of valve cover.
Hold a piece of stiff paper loosely over opening in valve cover. Allow engine to idle for one minute. Paper should be drawn against rubber grommet in valve cover by vacuum in crankcase. If vacuum is not present, check tubes for restrictions or obstructions.

EVAP Canister

EVAP canister is located in engine compartment. Canister has no moving parts. Check for loose, missing, cracked or broken connections and parts. Repair or replace as necessary. No liquid should be in canister.

PCV Valve

4.7L engines are equipped with a closed Positive Crankcase Ventilation (PCV) system. With engine running at curb idle, remove PCV valve from grommet. If valve is functioning properly, a hissing sound will be heard as air passes through valve.
With engine running, place finger over valve inlet. Strong vacuum should be felt at valve inlet. Stop engine. Remove and shake PCV valve to ensure a metallic clicking noise can be heard, indicating valve is free. Reinstall PCV valve.
Remove oil filler cap from valve cover. Hold a piece of stiff paper over opening. After allowing about one minute for crankcase pressure stabilization, paper should be drawn against opening.
If paper is held against opening, performance is okay. If paper is not held against opening, replace PCV valve and retest. If performance does not improve, inspect system for restrictions and clean as necessary.

FUEL DELIVERY

Note. For fuel system pressure testing, see BASIC DIAGNOSTIC PROCEDURES article.

Fuel Injectors

Disconnect injector from wiring harness. Connect ohmmeter on injector terminals. Resistance should be about 10.8-13.2 ohms at 68°F (20°C).

TIMING CONTROL SYSTEMS

Ignition timing is electronically controlled by Powertrain Control Module (PCM). Base ignition timing is NOT adjustable with this system. PCM controlled ignition system consists of engine coolant temperature sensor, crankshaft position sensor, distributor (except Grand Cherokee), camshaft position sensor, ignition coil, manifold absolute pressure sensor and throttle position sensor. See ENGINE SENSORS, SOLENOIDS & SWITCHES for component testing.

A/C Clutch Relay

See DTC P0645: A/C CLUTCH RELAY CIRCUIT in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Auto Shutdown (ASD) Relay

See DTC P1389: NO ASD RELAY OUTPUT VOLTAGE AT PCM in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Fuel Pump Relay

See DTC P1282: FUEL PUMP RELAY CONTROL CIRCUIT in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Radiator Fan Control Relay

See DTC P1491: RADIATOR FAN CONTROL RELAY CIRCUIT in CHRYSLER CORP. - SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Transmission Governor Pressure Solenoid Relay