INTRODUCTION
Before testing separate components or systems, perform procedures in BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in appropriate TESTS W/CODES - 5.2L article.
Note. Testing individual components does not isolate possible short or open circuits. Unless stated otherwise in test procedure, perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) having a minimum 10-megohm input impedance. Use ohmmeter to isolate wiring harness short or open circuits.
POWERTRAIN CONTROL MODULE (PCM)
The PCM power and ground circuits may be checked by performing TEST NTC-11A in BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in appropriate TESTS W/CODES - 5.2L article. Check power and ground circuits using a DVOM and wiring diagram in WIRING DIAGRAMS - 5.2L article. For PCM location, see PCM LOCATION table.
| Application | Location |
|---|---|
| Grand Cherokee | Right Front Fender, Near EVAP Canister |
PCM LOCATION
ENGINE SENSORS & SWITCHES
Note. In the following test, an analog type voltmeter must be used. Use a small piece of wire (paper clip) to access distributor connector terminals while connector is plugged in.
CAMSHAFT POSITION (CMP) SENSOR
See TEST TC-1A in BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in appropriate TESTS W/CODES - 5.2L article.
CRANKSHAFT POSITION (CKP) SENSOR
See TEST TC-40A in BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in appropriate TESTS W/CODES - 5.2L article.
ENGINE COOLANT TEMPERATURE (ECT) SENSOR
See TEST TC-30A and TC-31A in BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in TESTS W/CODES - 5.2L article.
Heating Element
See appropriate Trouble Code (TC) TEST in appropriate BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in TESTS W/CODES - 5.2L article.
INTAKE AIR TEMPERATURE (IAT) SENSOR
See TEST TC-57A and TC-58A in BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in appropriate TESTS W/CODES - 5.2L article.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
See TEST TC-36A and TC-37A in BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in TESTS W/CODES - 5.2L article.
PARK/NEUTRAL POSITION (PNP) SWITCH
See TEST TC-114A in BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in appropriate TESTS W/CODES - 5.2L article.
POWER STEERING PRESSURE (PSP) SWITCH
See TEST TC-114 in BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in appropriate TESTS W/CODES - 5.2L article. PSP switch is not used on Grand Cherokee.
THROTTLE POSITION (TP) SENSOR
- See appropriate Trouble Code (TC) TEST in appropriate «BASIC TESTING - 5.2L»(/jeep/grand-cherokee/zj-1996-1998/remont/testing-diagnostics/#engine-controls-basic-testing-52l) article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in «TESTS W/CODES - 5.2L»(/jeep/grand-cherokee/zj-1996-1998/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l) article.
VEHICLE SPEED SENSOR
See appropriate Trouble Code (TC) TEST in appropriate BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in TESTS W/CODES - 5.2L article.
Idle Air Control (IAC) Motor
See Trouble Code (TC) TEST in BASIC TESTING - 5.2L article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in TESTS W/CODES - 5.2L article.
A/C Clutch Relay, Automatic Shutdown (ASD) Relay, Fuel Pump Relay & Starter Motor Relay
- Remove relay from power distribution center in engine compartment. With relay in de-energized position, continuity should exist between relay terminals No. 87A and 30. (Scheme 87) No continuity should exist between terminals No. 87 and 30.
- Connect a jumper wire between positive battery terminal and relay terminal No. 86. Connect another jumper wire between battery negative terminal and relay terminal No. 85. Continuity should exist between relay terminal No. 30 and 87. No continuity should exist between relay terminals No. 87A and 30. If continuity is not as specified, replace relay.
Scheme 87
FUEL DELIVERY
Note. For fuel system pressure testing, see appropriate BASIC TESTING - 5.2L article.
Fuel Injectors
Disconnect injector from wiring harness. Connect ohmmeter on injector terminals. Resistance should be about 13.3-15.7 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 (includes rotor and camshaft position sensor), ignition coil, manifold absolute pressure sensor and throttle position sensor. See ENGINE SENSORS & SWITCHES for component testing.
PCV Valve
- 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 crankcase ventilation filter or 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.
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.