Engine Controls - System/component Tests: Other Ford Aerostar I

GROUND CIRCUITS

1. Using a DVOM, check for continuity to ground on ECA terminals No. 40 and 60. (Scheme 118) Resistance should be zero ohms. If resistance is not zero ohms, repair open to ground.
2. Using a voltmeter, touch negative lead of voltmeter to a good ground. Touch positive lead of voltmeter to each ground terminal. With vehicle running, the voltmeter should indicate less than one volt. If voltmeter reading is greater than one volt or more, check for open, corrosion or loose connection on ground lead.

POWER CIRCUITS

Using a voltmeter, check for battery voltage between ECA terminal No. 1 (KAPWR) and ground. Check for battery voltage at terminals No. 37 and 57 (VPWR). If battery voltage is not present, power is not being supplied from EEC power relay. See CIRCUIT TEST B in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section.

ECA LOCATION (1)

Scheme 118

Scheme 119

Scheme 120

Scheme 121

Scheme 122

ENGINE SENSORS & SWITCHES (ECA INPUTS)

Note. For additional sensor testing specifications, see SENSOR RANGE CHARTS article in the ENGINE PERFORMANCE Section.

AIR CHARGE TEMPERATURE (ACT) SENSOR

1. On 2.3L and 4.9L, sensor is located on intake runner number one. On 2.9L, sensor is located on top right side of engine above valve cover. On 3.0L and 4.0L, sensor is located on top left side of engine, behind idle air bypass valve. On 5.0L and 5.8L, sensor is located on top center of engine near intake runner number 6. On 7.5L, sensor is located behind distributor.
2. Sensor requires a 5-volt reference signal during engine operation. With sensor disconnected, sensor may be checked by measuring resistance between sensor terminals. For specifications, see SENSOR RANGE CHARTS article in the ENGINE PERFORMANCE Section. For additional testing information and circuit testing of sensor, see CIRCUIT TEST DA in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section.

BAROMETRIC PRESSURE SENSOR (BP)

Faults in barometric pressure sensor or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST DF in TESTS W/CODES EEC-IV article for sensor specifications.

CLUTCH SWITCH

See NEUTRAL DRIVE SWITCH (NDS) & A/C INPUT.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

Sensor is located in intake manifold cooling passage at front of most engines. On 2.3L, sensor is mounted on left side of engine above oil filter. Sensor requires a 5-volt reference signal during engine operation. With sensor disconnected, sensor may be checked by measuring resistance between sensor terminals. For specifications, see SENSOR RANGE CHARTS article in the ENGINE PERFORMANCE Section. For additional testing information and circuit testing of sensor, see CIRCUIT TEST DA in TESTS W/CODES EEC-IV article.

EGR VALVE POSITION (EVP) SENSOR/EGR VACUUM REGULATOR (EVR) SOLENOID

Faults in sensor or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST DN in TESTS W/CODES EEC-IV article for sensor specifications and circuit testing procedure.

ENGINE RPM SENSOR (RPMS)

This sensor is used only on diesel engines. Disconnect RPMS electrical connector. Using DVOM, measure resistance across sensor terminals. Resistance should be 2400-2800 ohms. Replace sensor if not as specified. Faults in RPMS or sensor circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST DJ in TESTS W/CODES EEC-IV article for additional sensor testing and specifications.

FUEL INJECTION PUMP LEVER (FIPL) SENSOR

This sensor may also be referred to as Throttle Position Sensor (TP Or TPS). Faults in FIPL sensor or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST DQ in TESTS W/CODES EEC-IV article for additional sensor testing and specifications. Ensure none of the following conditions exist.

1. Binding Throttle Or Speed Control Linkage
2. Idle Speed And Throttle Stop Improperly Adjusted
3. Choke/High Cam System Sticking

HEATED EXHAUST GAS OXYGEN (HEGO) SENSOR

Vehicle may be equipped with one or two HEGO sensors. They are located in the exhaust pipe upstream of the catalytic converters. Faults in sensor or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article. If no service code has been set, see CIRCUIT TEST H in TESTS W/CODES EEC-IV article for additional sensor specifications and circuit testing procedures. Ensure that none of the following conditions exist.

1. Moisture Inside Sensor/Harness Connector
2. HEGO Sensor Coated With Contaminants
3. Sensor Circuit Open Or Shorted To Ground

INERTIA SWITCH

Ensure key is off. Inertia switches may be found in the following locations

1. On Aerostar & "E" Series, on right kick panel, just forward of door opening.
2. On Bronco & "F" Series, on floorboard to left and above steering column.
3. On Explorer & Navajo, under instrument panel, to right of transmission hump.

Push down on reset button to ensure switch is closed. Measure resistance between terminals on switch. If resistance is 5 ohms or less, switch is okay. For additional circuit testing information refer to CIRCUIT TEST J in TESTS W/CODES EEC-IV article. If resistance is greater than 5 ohms, replace switch.

Note. In closed position, reset button can be depressed an additional 1/16" against spring. This is normal and does not affect switch operation.

KNOCK SENSOR (KS)

KS is located on cylinder block. Faults in sensor or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST DG in TESTS W/CODES EEC-IV article for additional sensor specifications and circuit testing procedures. Sensor is tested by substitution or by manually generating a knock to ensure sensor will set a service code.

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR

Sensor is located on engine or firewall and is connected to intake manifold by a vacuum supply hose. Remove vacuum supply hose to sensor. Install vacuum pump to sensor and apply 18 in. Hg vacuum. Sensor should hold vacuum. If sensor does not hold vacuum, replace sensor. Faults in MAP sensor or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST DF in TESTS W/CODES EEC-IV article for additional sensor testing and specifications.

MASS AIRFLOW (MAF) SENSOR

Faults in MAF sensor or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST DC in TESTS W/CODES EEC-IV article for sensor and circuit testing and specifications.

NEUTRAL DRIVE SWITCH (NDS) A/C INPUT

With ignition switch in OFF position, set DVOM to 200-ohm scale. Locate NDS switch (on transmission) and clutch switch (on clutch pedal linkage). Disconnect harness at both switches. Measure resistance across NDS terminals with transmission in Neutral and across clutch switch terminals with clutch pedal fully depressed. If each resistance is greater than 5 ohms, switches are open. Replace switches. Faults in switches or switch circuits should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST TA in TESTS W/CODES EEC-IV article for additional switch testing and specifications.

POWER STEERING PRESSURE SWITCH (PSPS)

1. Disconnect PSPS connector at steering gearbox. Set DVOM to 200-ohm scale and connect test leads to switch. With steering wheel centered, resistance should be less than 10 ohms. Start engine and turn steering wheel one-half turn and then return it to centered position.
2. Resistance should change from less than 10 ohms to infinity and return to less than 10 ohms when steering wheel is returned to centered position. Faulty PSPS or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST FF in TESTS W/CODES EEC-IV article for additional switch testing and specifications.

THROTTLE POSITION SENSOR (TP OR TPS)

Faults in TP sensor or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST DH in TESTS W/CODES EEC-IV article for additional sensor testing and specifications. Ensure none of the following conditions exist

1. Binding Throttle Linkage
2. TP Sensor Loose Or Not Seated Properly
3. Throttle Plate Not Fully Closed

VEHICLE SPEED SENSOR (VSS)

Disconnect VSS electrical connector. Using DVOM measure resistance across sensor terminals. Resistance should be 190-250 ohms. Replace sensor if not within specification. Faults in VSS sensor or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article. If no service code has been set, see CIRCUIT TEST DP in TESTS W/CODES EEC-IV article for additional sensor testing and specifications.

Fuel Pump Relay

Remove relay from vehicle. Connect battery voltage to terminal "C". Ground terminal "D". (Scheme 123) Measure resistance between terminals "A" and "B". Resistance should be less than one ohm with power applied and greater than 10 k/ohms with power removed.

Note. For more fuel delivery system testing, see CIRCUIT TEST J in TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Scheme 123

Air Management Solenoids (AM1 & AM2)

Disconnect solenoid harness connectors, and measure resistance across terminals. Resistance should be 50-100 ohms. If resistance is not as specified, replace solenoid. Faults in AM1 or AM2 solenoids or circuits should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST KC in TESTS W/CODES EEC-IV article for additional solenoid and circuit testing.

Canister Purge (CANP) Solenoid

See FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS.

EGR Solenoid

See EXHAUST GAS RECIRCULATION under EMISSION SYSTEMS & SUB-SYSTEMS.

Idle Speed Control (ISC) Solenoid

1. Solenoid is by-pass air type solenoid. Ensure ignition is off. Disconnect ISC solenoid harness connector. Set DVOM to 200-ohm scale. Measure resistance between ISC solenoid terminals. (Scheme 124) There is a diode in solenoid, connect DVOM (+) test lead to VPWR terminal and DVOM (-) lead to ISC terminal.
2. Resistance should be 7-13 ohms. If resistance is not as specified, replace solenoid. Faults in ISC solenoid or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article. If no service code has been set, see CIRCUIT TEST KE in TESTS W/CODES EEC-IV article for additional solenoid testing and specifications.

Scheme 124

FUEL SYSTEM

Note. In testing procedures, references to KOEO refer to Key On Engine Off. References to KOER refer to Key On Engine Running.

FUEL SYSTEM PRESSURE RELEASE

1. Remove fuel tank cap. Using Fuel Pressure Gauge (T80L-9974-B), release pressure from system at pressure relief valve (Schrader valve), located on fuel injection manifold rail.
2. If fuel pressure gauge is not available, disconnect electrical connector to inertia switch located on left side of luggage compartment. Remove fuel cap to release fuel tank pressure. Crank engine for 15 seconds to reduce system pressure.

FUEL SELECTOR VALVE (DIESEL)

Remove fuel selector valve. Perform checks as indicated in FUEL SELECTOR VALVE SPECIFICATION table. (Scheme 125) Replace selector valve if operation is not correct.

Scheme 125

Fuel Injectors

1. Connect tachometer to engine. Run engine at idle. Disconnect and reconnect injectors individually. If each injector causes a momentary drop in engine speed of at least 100 RPM, injectors are giving proper fuel delivery. RPM drop should only be momentary as ISC will attempt to re-establish correct idle RPM.
2. Replace any injectors that do not cause sufficient drop in engine speed. When test is complete and all injectors cause equal drop in speed, shut off engine. In order to check curb idle, refer to emission control specifications on decal in engine compartment.

Injector Circuit

1. Disconnect all injector harness connectors. Using digital ohmmeter, check resistance across terminals of each injector. See appropriate INJECTOR RESISTANCE table.
2. Disconnect injector bank harness connector, and check resistance of injector bank. See «INJECTOR BANK RESISTANCE»(ref-22719-S19599033262001010300000) . Repair wiring or replace any injector circuit not within specification.

INDIVIDUAL INJECTOR RESISTANCE

INJECTOR BANK RESISTANCE

IDLE CONTROL SYSTEM

Note. See IDLE SPEED CONTROL (ISC) SOLENOID test procedures under SOLENOIDS. Curb idle and fast idle speed is controlled by ECA and is not adjustable. Some throttle bodies have a sludge-tolerant design with a special coated throttle bore. A Yellow/Black warning decal on these units warns against backing off throttle plate adjustment screw to avoid throttle plate sticking in bore. Faults in idle control system components or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section.

TFI-IV SYSTEM IGNITION

Note. Before testing components and circuits of this system, ensure system is identified as to location of TFI module (distributor mounted or CBD type). Additional system and circuit testing for this system is located in appropriate CIRCUIT TESTS in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section.

PRELIMINARY CHECK

Ensure the following preliminary checks have been performed

1. Visually inspect engine compartment to ensure all vacuum hoses and spark plug wires are properly routed and securely connected.
2. Examine all wiring harnesses and connectors for damage.
3. Ensure TFI module is securely fastened to distributor base or cowl.
4. Ensure battery is fully charged.
5. Turn all accessories off during diagnosis.

DIS SYSTEM (2.3L RANGER)

Note. Start all diagnostics with EEC-IV Quick Test. See TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. These tests are dependent on results and service codes received during Quick Test procedures.

Ensure following preliminary checks have been performed

1. Visually inspect engine compartment to ensure all vacuum hoses and spark plug wires are properly and securely connected.
2. Check all wiring harnesses and connectors for damaged insulation, burned, overheating, damaged pins, loose or broken conditions. Check sensor shield connector. Ensure DIS module mounting screws are tight.
3. Ensure battery is fully charged.
4. Turn all accessories off during diagnosis.

EDIS SYSTEM (4.0L AEROSTAR, EXPLORER, NAVAJO & RANGER)

Note. Start all diagnostics with charts in TESTS W/O CODES article in the ENGINE PERFORMANCE Section. Perform Quick Test procedure in TESTS W/CODES EEC-IV article before entering this test. These tests are dependent on results of Quick Test procedure.

Note. The EDIS Diagnostic Cable (Rotunda 007-00059) should be used to diagnose this system. This cable is equipped with additional circuits and components used to enhance and modify signals for testing purposes. If an aftermarket test cable is used, or diagnosis is being performed using only a DVOM, ensure technician is familiar with system wiring diagram and system operation.

PRELIMINARY CHECKOUT

Visually inspect the engine compartment to ensure all vacuum hoses and spark plug wires are properly and securely connected. Examine all wiring harnesses and connectors for damaged insulation, burned, overheated, damaged pins, loose or broken conditions. Check sensor shield connector. Ensure EDIS module mounting screw is tight. Ensure battery is fully charged and all accessories are off during diagnosis.

Air Supply Pump

Check belt tension and adjust to proper tension, if necessary. Disconnect air supply hose from by-pass control valve. Start engine. Pump is operating satisfactorily if airflow is felt at pump outlet and airflow increases as engine speed is increased. If this condition is not met, replace pump.

Air Silencer/Filter (Air Pump & Pulse Air Inlet)

Inspect hoses and air silencer for leaks. Disconnect hose from air silencer outlet. Remove silencer from vehicle, and visually inspect for plugging. If no plugging or leaks are found, silencer is okay. If any plugging or leaks are found, repair or replace as required.

Scheme 126

1. Disconnect air supply hose at valve outlet. (Scheme 127) Remove vacuum line from vacuum nipple and check for presence of vacuum at nipple. There must be vacuum present at nipple before proceeding.
2. Reconnect vacuum line to vacuum nipple. With engine at 1500 RPM, air pump supply air should be heard and felt at air by-pass valve outlet.
3. With engine still at 1500 RPM, disconnect vacuum line. Air at outlet should decrease significantly or shut off. Air pump supply air should now be heard or felt at silencer ports or at dump port.
4. If the normally closed air by-pass valve does not perform as described in steps 2) and 3), check the air pump for faults. If air pump is operating satisfactorily, replace air by-pass valve.

Air Check Valve

1. Visually inspect thermactor hoses, tubes, control valve(s) and check valve(s) for leaks that may be due to backflow of exhaust gases. If holes are found and/or traces of exhaust gas products are evident, check valve may be suspect.
2. Valve should allow free flow of air in direction of arrow only. (Scheme 128) The valve(s) should check (or block) the free flow of exhaust gas air in the opposite direction.
3. If air does not flow as indicated or if exhaust gas backflows opposite of direction of arrow in illustration, replace check valve.

Scheme 127

Scheme 128

1. Disconnect air supply hose at inlet. Accelerate engine to 1500 RPM and verify presence of airflow in hose. Reconnect air supply hose to valve inlet.
2. Disconnect air supply hoses at outlets "A" and "B". (Scheme 129) Remove vacuum line at vacuum nipple. Accelerate engine to 1500 RPM. Airflow should be heard and felt at outlet "B" with little or no airflow at outlet "A".
3. Connect a vacuum line from manifold vacuum fitting to air supply control valve vacuum nipple. Accelerate engine to 1500 RPM. Airflow should be heard and felt at outlet "A" with little or no airflow at outlet "B".
4. If valve does not meet above conditions, replace valve. If airflow operates as described in steps 1), 2) and 3), valve is okay. Reinstall hoses and clamps.

Scheme 129

1. Disconnect air supply hose at inlet. Accelerate engine to 1500 RPM and verify presence of airflow in hose. Reconnect air supply hose to valve inlet.
2. Carefully disconnect the air supply hoses at outlets "A" and "B". (Scheme 130) Carefully remove vacuum line at vacuum nipple. Accelerate engine to 1500 RPM. Airflow should be heard and felt at outlet "B" with little or no airflow at outlet "A".
3. Connect a vacuum line from manifold vacuum fitting to air control valve vacuum nipple. Accelerate engine to 1500 RPM. Airflow should be heard and felt at outlet "A" with little or no airflow at outlet "B".
4. If the conditions in steps 2) and 3) are not met, replace the air control valve. If the valve operates satisfactorily, restore all hose and vacuum connections.

Air Pump Resonator

Visually inspect for holes. Remove hoses and check for restricted ports. Replace resonator if holes or ports are restricted. Reconnect hoses and install clamps.

Scheme 130

1. Disconnect hoses from outlets "A" and "B". (Scheme 131) Disconnect and plug vacuum line to port "D". With engine operating at 1500 RPM, airflow should be noted coming out of by-pass vents.
2. Reconnect vacuum line to port "D". Disconnect and plug vacuum line to port "S". Ensure vacuum is present in line to vacuum port "D". Accelerate engine to 1500 RPM. Airflow should be noted coming out of outlet "B". No airflow should be detected at outlet "A".
3. Apply 8-10 in. Hg vacuum to port "S". With engine operating at 1500 RPM, airflow should be noted coming out of outlet "A". If valve is bleed type, less air will flow from outlet "A" or "B", and the main discharge will change when vacuum is applied to port "S".
4. If the conditions in the above steps are not met, replace valve. If above conditions are met, valve is okay. Reconnect hoses and vacuum lines.

Dual Thermactor Air Control Solenoid Valve

Function of each valve can be determined by externally energizing valve with vacuum lines attached. Check resistance of each solenoid. Resistance should be 51-108 ohms when checked at coil terminals. If resistance is not 51-108 ohms, solenoid should be replaced.

Thermactor Idle Vacuum (TIV) Valve

1. With engine at idle and transmission in NEUTRAL, apply vacuum to small nipple and place fingers over the TIV valve atmospheric vent holes. (Scheme 132) If no vacuum is sensed, the TIV is damaged and must be replaced. If vacuum is sensed, go to next step.
2. With engine still at idle, apply vacuum to TIV valve large nipple from using a vacuum pump. See «TIV VALVE (LARGE NIPPLE) VACUUM SPECIFICATIONS»(ref-22719-S03656049652001010300000). If vacuum is not held, the TIV is damaged and must be replaced. If no vacuum is sensed, replace valve.

Scheme 131

TIV VALVE (LARGE NIPPLE) VACUUM SPECIFICATIONS

Scheme 132

1. A 2-port valve may be in open or closed position when engine is cold, but should reverse when engine is warmed to operating temperature.
2. For 3-port valves, with a cold engine, passage "A" to "B" should be closed and passage "A" to "C" should be open. (Scheme 133) With engine at normal operating temperature, the VCV should be open between "A" and "B" and closed between "A" and "C".
3. For the 4-port valve, check "A[I1]" to "B[I1]" and "A[I2]" to "B[I2]" separately. (Scheme 133) A 4-port valve may be in open or closed position when engine is cold, but should reverse when engine is warmed to operating temperature. If these conditions are not met, replace the valve.

Scheme 133

1. Electrical vacuum control valve may be either open or closed at room temperature, but should reverse the position when engine is at full operating temperature. While engine is cold, measure continuity across switch terminals. see scheme 29 Note if switch is open or closed.
2. Warm engine to normal operating temperature. Measure continuity across switch terminals again. Continuity should be opposite of cold condition. If switch continuity does not switch, replace valve. Check vacuum function of valve as described in VACUUM CONTROL VALVE.

Vacuum Check Valve

Apply 16 in. Hg vacuum to check side of valve and trap. If vacuum remains greater than 15 in. Hg for 10 seconds, valve operation is normal. If vacuum drops faster, replace valve.

Vacuum Reservoir

When charged with 15-20 in. Hg vacuum, vacuum loss should not exceed .5 in. Hg in 60 seconds. If vacuum loss is faster, replace reservoir.

Pulse Air Valve

With engine at normal operating temperature and at curb idle, remove inlet hose from valve. A suction should be felt at valve inlet. If suction is not felt, replace valve.

Electronic EGR Valve (EEGR) & Pressure Feedback Electronic (PFE)

Note. EVR solenoid has a constant internal leak. You will notice a small vacuum signal of less than 1 in. Hg vacuum at idle.

1. Ensure all vacuum hoses are correctly routed and securely attached. Replace any crimped or broken hoses. Ensure there is less than 1 in. Hg vacuum to EGR valve at idle with engine at normal operating temperature.
2. Install tachometer. Disconnect Idle Air By-Pass Valve electrical connector (if equipped). Remove and plug vacuum hose at EGR valve. Start engine and idle in neutral. Note idle speed. Using hand vacuum pump, slowly apply 5-10 in. Hg vacuum to EGR valve. When vacuum is fully applied to EGR valve, engine should do one or more of the following: Engine should stall. Idle speed should drop more than 100 RPM. Idle speed should return to normal when vacuum is released.
3. Repair or replace EGR valve if none of the above occurs. Reconnect idle air by-pass valve electrical connector. Unplug and reconnect vacuum hose at EGR valve.

EGR Vacuum Regulator (EVR)

Faults in EVR or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST DN in TESTS W/CODES EEC-IV article for diagnostic procedures.

On 2.3L Ranger (1989-91), intermittent operation or failure of EVR may be caused by water in EVR or vacuum hoses connected to it. If water or moisture is found in EVR or hoses connected to it, install new service part, available from manufacturer, in an inverted position. Use shop air to clear water and moisture from vacuum hoses. Clear Continuous Memory Codes if set and run Quick Test to verify repair.

Remove EGR solenoid harness connector. Measure resistance across solenoid terminals. Resistance should be 65-110 ohms. Set DVOM to 200-k/ohm scale. Measure resistance between each solenoid terminal and ground or side of solenoid. Resistance should be 10 k/ohms or more. If resistance is not as specified in either test, replace solenoid.

Apply 16 in. Hg vacuum to check side of valve and trap. If vacuum remains greater than 15 in. Hg for 10 seconds, valve operation is normal. If not, replace valve.

When charged with 15-20 in. Hg vacuum, vacuum loss should not exceed .5 in. Hg in 60 seconds. If it does, replace reservoir.

Canister Purge Regulator (CPR) Valve

With CPR valve de-energized, apply 5 in. Hg vacuum to source port. Valve should not pass air. Apply 9-14 volts to one electrical terminal and ground the other. Valve should open and pass air. If valve does not operate as described, replace valve.

1. Disconnect CANP solenoid harness connector. Set DVOM to 200-ohm scale. Measure resistance across CANP solenoid terminals. Resistance should be 40-90 ohms. If resistance is not as specified, replace CANP solenoid.
2. Disconnect vacuum hose at CANP solenoid on manifold vacuum side. Apply 16 in. Hg vacuum to manifold vacuum side of solenoid. CANP solenoid should hold vacuum for 20 seconds.
3. Faults in CANP solenoid or circuit should set a service code. See Quick Test procedure in TESTS W/CODES EEC-IV article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST KD in TESTS W/CODES EEC-IV article for additional solenoid and circuit testing.

EVAP Canister

There are no moving parts in canister. Check for loose, missing, cracked or broken connections or parts. Repair or replace as necessary. There should be no liquid in canister.

PCV Valve

1. Remove PCV valve from rocker cover grommet. Shake valve. Valve should rattle when shaken. If valve does not rattle, replace valve.
2. Start engine and warm to normal operating temperature. On 2.3L, 2.9L and 4.9L engines, remove corrugated hose from oil separator nipple. Place stiff piece of paper over nipple end and wait 60 seconds.
3. On all other engines, disconnect hose from remote air cleaner or outlet tube. Place stiff piece of paper over hose end and wait 60 seconds. Vacuum should hold paper in place. If vacuum does not hold paper in place, replace valve.

Air Cleaner Temperature Sensor

Bring temperature of sensor to less than 75°F (24°C), and apply 8 in. Hg vacuum to source port. Duct door should close. If door does not close, replace sensor. Sensor will bleed off vacuum to allow duct door to open and let in fresh air at specific temperatures. See AIR CLEANER TEMPERATURE SENSOR OPENING .

AIR CLEANER TEMPERATURE SENSOR OPENING

Air Control Door

When a vacuum of 8 in. Hg or more is applied to vacuum motor, door should stay in proper position for as long as vacuum is applied. If vacuum bleeds off and door returns to rest position, replace vacuum motor.