Engine Controls - System/component Tests - 3.0L: Other Dodge Caravan III

POWERTRAIN CONTROL MODULE (PCM)

The PCM is located between driver's side front fender and power distribution center, near the battery. The PCM power and ground circuits may be checked by performing specified No Trouble Code (NTC) test. See TEST NTC-11A CHECKING PCM POWER & GROUND CIRCUITS in TESTS W/CODES article.

A/C Pressure Sensor

1. A/C pressure sensor may also be referred to as A/C pressure switch or A/C pressure transducer. The A/C pressure sensor is located on A/C refrigerant line on firewall, near front of generator and contains a Gray 4-pin electrical connector.
2. Ensure work area around A/C pressure sensor is not less than 50°F (10°C). Apply parking brake. Ensure shift lever is in Park or Neutral. Start engine and allow engine to idle.
3. Connect scan tool to Data Link Connector (DLC). For DLC location, see TESTS W/CODES article.
4. Go to main menu on scan tool. Select STAND ALONE on scan tool, and then select 1997 DIAGNOSTICS. Select CLIMATE CONTROL and then SENSOR DISPLAY. Select A/C HIGH SIDE VOLTS on scan tool and note voltage display.
5. For A/C system operation, a voltage between .451 volt (low-pressure cutout) to 4.519 volts (high-pressure cutout) is required. Using displayed voltage, determine if A/C pressure sensor operates correctly. See A/C PRESSURE SENSOR SPECIFICATIONS table. Replace A/C pressure sensor if defective.

A/C PRESSURE SENSOR SPECIFICATIONS

Camshaft Position Sensor

1. Camshaft position sensor is located in the distributor with connector located on outside of distributor.
2. Individual component testing is not available. If camshaft position sensor or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM).

Crankshaft Position Sensor

1. Crankshaft position sensor is located on top of transaxle housing, above flywheel, near corner of rear exhaust manifold.
2. Individual component testing is not available. If crankshaft position sensor or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

Downstream Oxygen Sensor

1. Downstream oxygen sensor is mounted on exhaust pipe behind catalytic converter. Only individual component testing available is for the oxygen sensor heater.
2. Disconnect electrical connector at downstream oxygen sensor. Using ohmmeter, check resistance between White wires in electrical connector for downstream oxygen sensor. Replace downstream oxygen sensor if resistance is not 4-7 ohms.
3. If downstream oxygen sensor or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

Engine Coolant Temperature Sensor

1. Engine coolant temperature sensor is located near thermostat housing and contains a Black/Light Blue wire and a Tan/Black wire in the electrical connector. Disconnect electrical connector at engine coolant temperature sensor.
2. Using ohmmeter, measure resistance between electrical terminals on engine coolant temperature sensor. With engine coolant temperature of approximately 200°F (93°C), resistance should be approximately 700-1000 ohms. With engine coolant temperature of approximately 70°F (21°C), resistance should be approximately 7000-13,000 ohms.
3. If engine coolant temperature sensor or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

Manifold Absolute Pressure (MAP) Sensor

For MAP sensor location, see MAP SENSOR LOCATIONS table. If MAP sensor or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

MAP SENSOR LOCATIONS

Throttle Position Sensor

1. Remove components for access to electrical connector at Throttle Position (TP) sensor mounted on throttle body. With electrical connector installed on TP sensor, turn ignition on with engine off. DO NOT start engine.
2. Using digital volt-ohmmeter, measure voltage at center terminal on electrical connector for TP sensor with throttle valve closed (idle position). Voltage should be .38-1.20 volts.
3. Slowly open throttle to full throttle and note voltage reading. Voltage should smoothly increase to 3.10-4.40 volts. If TP sensor or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

Transmission Range Sensor (4-Speed A/T)

Transmission range sensor is located on side of transaxle and may also be referred to as park/neutral switch. (Scheme 221) Individual component testing information is not available.

Scheme 221

Upstream Oxygen Sensor

1. Upstream oxygen sensor is mounted on exhaust manifold. Only individual component testing available is for the oxygen sensor heater.
2. Disconnect electrical connector at upstream oxygen sensor. Using ohmmeter, check resistance between White wires in electrical connector for upstream oxygen sensor. Replace upstream oxygen sensor if resistance is not 4-7 ohms.
3. If upstream oxygen sensor or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

Vehicle Speed Sensor (3-Speed A/T)

1. Vehicle speed sensor is mounted on extension housing for passenger's side axle shaft at firewall side of transaxle. (Scheme 222)
2. Individual component testing is not available. If vehicle speed sensor or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

Scheme 222

A/C Switch

A/C switch is located on heating and A/C control panel at center of instrument panel near the stereo. Individual component testing is not available.

Brake Switch

1. Remove lower cover from instrument panel for access to brake switch. Brake switch is located near top of brake pedal.
2. Depress locking tabs on electrical connector and disconnect electrical connector from brake switch. It may be necessary to remove brake switch for access to electrical connector. If necessary to remove brake switch, see REMOVE/INSTALL/OVERHAUL article.
3. Pull plunger on brake switch fully outward. (Scheme 223) Using ohmmeter, check for continuity between terminals No. 5 and 6 on brake switch. (Scheme 223) Continuity should exist.
4. Push plunger on brake switch fully inward. Using ohmmeter, check for continuity between terminals No. 1 and 2, and 3 and 4 on brake switch. (Scheme 223) Continuity should exist. If continuity is not as specified, replace brake switch.

Scheme 223

Park/Neutral Switch (3-Speed A/T)

Park/neutral switch is located on side of transaxle. (Scheme 224) Individual component testing is not available. If park/neutral switch or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

Park/Neutral Switch (4-Speed A/T)

Park/neutral switch may be referred to as transmission range sensor. See TRANSMISSION RANGE SENSOR (4-SPEED A/T) under SENSORS under ENGINE SENSORS & SWITCHES.

Scheme 224

Idle Air Control Motor

See IDLE AIR CONTROL MOTOR under IDLE CONTROL SYSTEM.

A/C Clutch Relay

See RELAYS under MISCELLANEOUS CONTROLS .

Auto Shutdown (ASD) Relay

See RELAYS under MISCELLANEOUS CONTROLS .

Fuel Pump Relay

See FUEL DELIVERY under FUEL SYSTEM.

Radiator Fan Control Relay

See RELAYS under MISCELLANEOUS CONTROLS .

Starter Relay

See RELAYS under MISCELLANEOUS CONTROLS .

EGR Solenoid

See EXHAUST GAS RECIRCULATION (EGR) SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS.

EVAP Purge Solenoid

See EVAPORATIVE (EVAP) EMISSIONS SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS.

FUEL DELIVERY

Note. For fuel system pressure testing, see BASIC TESTING article.

1. Remove fuel pump relay from power distribution center at driver's side front corner of engine compartment, near the battery. Note terminal identification on fuel pump relay. (Scheme 225)
2. To check fuel pump relay resistance, use ohmmeter and check resistance between terminals No. 85 and 86 on fuel pump relay. Replace fuel pump relay if resistance is not 70-80 ohms.
3. To check fuel pump relay operation, connect ohmmeter between terminals No. 30 and 87A on fuel pump relay. (Scheme 225) Ohmmeter should indicate continuity between terminals No. 30 and 87A on fuel pump relay.
4. Connect ohmmeter between terminals No. 30 and 87 on fuel pump relay. (Scheme 225) Ohmmeter should indicate no continuity between terminals No. 30 and 87 on fuel pump relay.
5. Connect 16-gauge jumper wire between negative battery terminal and terminal No. 85 on fuel pump relay. Connect 16-gauge jumper wire between positive battery terminal and terminal No. 86 on fuel pump relay.
6. Continuity should now exist between terminals No. 30 and 87 on fuel pump relay. No continuity should now exist between terminals No. 30 and 87A on fuel pump relay. Disconnect jumper wires. Replace fuel pump relay if defective.
7. If fuel pump relay or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

Scheme 225

Fuel Pressure Regulator

Fuel pressure regulator is a nonadjustable in-tank pressure regulator mounted on fuel pump module on top of fuel tank. Individual component testing is not available.

See RELAYS under MISCELLANEOUS CONTROLS .

Fuel Injector

Disconnect electrical connector at fuel injector. Using ohmmeter, check resistance between electrical terminals on fuel injector. Replace fuel injector if resistance is not 10-16 ohms at 68°F (20°C).

Idle Air Control (IAC) motor is mounted on the throttle body and contains a 4-pin electrical connector. Individual component testing is not available. If IAC motor or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

IGNITION SYSTEM

Note. For basic ignition checks, see BASIC TESTING article.

EXHAUST GAS RECIRCULATION (EGR) SYSTEM

Note. EGR valve, EGR backpressure transducer and EGR solenoid are serviced as a complete assembly.

EVAP Canister

EVAP canister is located on frame rail, directly below the driver's seat. Individual component testing is not available.

The EVAP purge solenoid is located near passenger's side strut tower. Individual component testing is not available. If EVAP purge solenoid or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

Leak Detection Pump

Leak detection pump is located below the driver's side of steering gear, above engine cradle. Individual component testing is not available. If leak detection pump or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

Fuel Tank Pressure Release/Rollover Valve

Fuel tank pressure release/rollover valve is located on fuel tank filler tube, just below fuel tank cap. Individual component testing is not available.

PCV Valve

1. Start engine and allow engine to idle. Remove PCV valve. Ensure vacuum hose is still connected on PCV valve.
2. Place finger over end of PCV with engine idling. Vacuum should exist at end of PCV valve. Turn engine off. Shake PCV valve and ensure rattle sound is heard to indicate free movement of PCV valve. Replace PCV valve if defective. DO NOT attempt to clean PCV valve.

MISCELLANEOUS CONTROLS

Note. Although some of the controlled devices listed here are not technically engine performance components, they can affect drive-ability if they malfunction.

1. The A/C clutch relay is located in power distribution center at driver's side front corner of engine compartment, near the battery. Individual component testing is not available.
2. If A/C clutch relay or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

1. Remove ASD relay from power distribution center. Power distribution center at driver's side front corner of engine compartment, near the battery. Note terminal identification on ASD relay. (Scheme 225)
2. To check ASD relay resistance, use ohmmeter and check resistance between terminals No. 85 and 86 on ASD relay. Replace ASD relay if resistance is not 70-80 ohms.
3. To check ASD relay operation, connect ohmmeter between terminals No. 30 and 87A on ASD relay. (Scheme 225) Ohmmeter should indicate continuity between terminals No. 30 and 87A on ASD relay.
4. Connect ohmmeter between terminals No. 30 and 87 on ASD relay. (Scheme 225) Ohmmeter should indicate no continuity between terminals No. 30 and 87 on ASD relay.
5. Connect 16-gauge jumper wire between negative battery terminal and terminal No. 85 on ASD relay. Connect 16-gauge jumper wire between positive battery terminal and terminal No. 86 on ASD relay.
6. Continuity should now exist between terminals No. 30 and 87 on ASD relay. No continuity should now exist between terminals No. 30 and 87A on ASD relay. Disconnect jumper wires. Replace ASD relay if defective.
7. If ASD relay or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

1. Radiator fan control relay may be referred to as radiator fan relay. Radiator fan control relay is located near driver's side frame rail and air cleaner lower mount. (Scheme 226) Individual component testing is not available.
2. If radiator fan control relay or wiring circuit failure exists, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See TESTS W/CODES article.

Scheme 226

1. Remove starter relay from power distribution center at driver's side front corner of engine compartment, near the battery. Note terminal identification on starter relay. (Scheme 227)
2. To check starter relay resistance, use ohmmeter and check resistance between terminals No. 85 and 86 on starter relay. Replace starter relay if resistance is not 70-80 ohms.
3. To check starter relay operation, connect ohmmeter between terminals No. 30 and 87A on starter relay. (Scheme 227) Ohmmeter should indicate continuity between terminals No. 30 and 87A on starter relay.
4. Connect ohmmeter between terminals No. 30 and 87 on starter relay. (Scheme 227) Ohmmeter should indicate no continuity between terminals No. 30 and 87 on starter relay.
5. Connect jumper wire between negative battery terminal and terminal No. 85 on starter relay. Connect jumper wire between positive battery terminal and terminal No. 86 on starter relay.
6. Continuity should now exist between terminals No. 30 and 87 on starter relay. No continuity should now exist between terminals No. 30 and 87A on starter relay. Disconnect jumper wires. Replace starter relay if defective.

Scheme 227