Engine Controls - System/component Tests: Other Eagle Summit I

CONTROL UNIT

Note. For Engine Control Unit (ECU) location, see ENGINE CONTROL UNIT (ECU) LOCATION table. To identify ECU power and ground circuits, see WIRING DIAGRAMS article.

Ground Circuits

1. Turn ignition off. Using an ohmmeter, check continuity between chassis ground and ECU ground terminals. See «GROUND TERMINAL IDENTIFICATION»(ref-18871-S25581531452000123000000) table. Ohmmeter should indicate zero ohms. If reading is not zero ohms, repair open circuit between ECU connector and ground.
2. Connect voltmeter negative lead to chassis ground. Connect positive lead to ECU ground terminals. See «GROUND TERMINAL IDENTIFICATION»(ref-18871-S25581531452000123000000) table. With engine running, voltmeter should indicate less than one volt. If voltmeter reading is greater than one volt, check for open, corrosion or loose connection in ground circuit. GROUND TERMINAL IDENTIFICATION Application ECU Terminal Mirage 101 & 106

Power Circuits

Turn ignition on. Check for battery voltage on ECU power terminals 102 & 107. If battery voltage is not present, check operation of MPI control relay near right kick panel.

POWER TERMINAL IDENTIFICATION

ENGINE CONTROL UNIT (ECU) LOCATION

BAROMETRIC PRESSURE SENSOR

Sensor is a part of airflow sensor assembly. See TESTS W/CODES article.

COOLANT TEMPERATURE SENSOR

1. Remove coolant temperature sensor. Sensor is located near thermostat housing (2-wire connector). Place end of sensor in water, with terminal connector portion of sensor slightly above water.
2. Gradually heat water, and read resistance values across terminal connectors. See «COOLANT TEMPERATURE SENSOR RESISTANCE»(ref-18871-S30725820682000123000000) table. If resistance is not within specification, replace sensor. COOLANT TEMPERATURE SENSOR RESISTANCE Temperature °F (°C) Resistance Ohms Mirage 32 (0) 5900 68 (20) 2500 104 (40) 2700 176 (80) 300 All Others 32 (0) 5800 68 (20) 2400 104 (40) 1100 176 (80) 300

CRANK ANGLE SENSOR

See IGNITION SYSTEM .

DETONATION SENSOR

See IGNITION SYSTEM .

EGR TEMPERATURE SENSOR (CALIFORNIA)

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

IDLE POSITION SWITCH - 1.5L

1. Disconnect Motor Position Sensor (MPS) connector. Connect ohmmeter lead between ground and MPS connector terminal No. 4. (Scheme 24)
2. With accelerator pedal pressed, no continuity should be present. With accelerator pedal released, continuity should be present. If switch continuity is not as specified, replace Idle Speed Control Servo assembly.

IDLE POSITION SWITCH - MIRAGE 1.6L DOHC

1. Disconnect idle position switch single-wire connector. Check for continuity between switch terminal and switch body (ground).
2. With accelerator pedal pressed, no continuity should be present. With accelerator released, continuity should be present. If idle position switch continuity is not as specified, replace idle position switch.

INHIBITOR SWITCH (AUTOMATIC TRANSMISSION)

Switch is mounted to automatic transaxle, near shift lever mechanism. Testing information is not available from manufacturer. See WIRING DIAGRAMS article.

Scheme 23

1. Sensor is incorporated in airflow sensor assembly inside air filter housing. Disconnect airflow sensor connector. (Scheme 23)
2. Measure resistance between terminals No. 4 and 6 of airflow sensor connector (sensor side of connector).
3. Replace airflow sensor assembly if air temperature sensor resistance is not within specification. See «INTAKE AIR TEMPERATURE SENSOR RESISTANCE»(ref-18871-S20337895792000123000000) table. INTAKE AIR TEMPERATURE SENSOR RESISTANCE Temperature °F (°C) Resistance Ohms 32 (0) 6000 68 (20) 2700 176 (80) 400 NOTE: Some engines are not equipped with Motor Position Sensor (MPS). MPS may be a separate unit mounted to throttle body or it may be incorporated in ISC motor assembly, depending on vehicle application.

Scheme 24

1. Disconnect MPS connector. (Scheme 24) Connect ohmmeter lead to ground. Connect other ohmmeter lead to terminal No. 3 of sensor connector. If continuity is not present, repair wiring harness as necessary. If continuity is present, go to next step.
2. Connect ohmmeter leads to terminals No. 2 and 3. Resistance for all models should be 4000-6000 ohms. If resistance is not within specified range, replace MPS. CAUTION: DO NOT apply more than 6 volts to ISC motor.
3. Operate ISC motor by connecting a 6-volt source directly to appropriate terminals of ISC motor connector. See «IDLE SPEED CONTROL (ISC) MOTOR OPERATION TEST»(ref-18871-S12029560812000123000000) under IDLE CONTROL SYSTEM.
4. While operating ISC motor, measure resistance between MPS connector terminals No. 3 and 5. Observe ohmmeter during ISC motor operation. If MPS resistance does not vary within a 4000-6000 ohm range or if resistance does not change smoothly, replace MPS (vehicles with separate MPS) or ISC motor assembly (vehicles with MPS incorporated in ISC).

Scheme 25

1. On all models, warm engine until coolant temperature is 185-205°F (85-96°C). Disconnect O2 sensor connector. (Scheme 25)
2. Connect digital voltmeter between terminal No. 1 and ground. Repeatedly race engine and observe O2 sensor output voltage. If output is not 0.6-1.0 volt, replace O2 sensor.

Scheme 26

1. Warm engine until coolant temperature is 185-205°F (85-95°C). Disconnect O2 sensor connector. (Scheme 26) Check resistance of O2 sensor heater element. Connect ohmmeter between specified heater terminals of O2 sensor connector. See «O2 SENSOR 4-WIRE CONNECTOR TERMINAL IDENTIFICATION»(ref-18871-S41475955232000123000000) table.
2. When O2 sensor is at 68°F (20°C), resistance should be approximately 12 ohms. If resistance is not within specification, replace O2 sensor. CAUTION: DO NOT apply battery voltage to O2 sensor output terminals; damage to O2 sensor could result.
3. Heat O2 sensor heater element by applying battery voltage to specified heater terminals. See «O2 SENSOR 4-WIRE CONNECTOR TERMINAL IDENTIFICATION»(ref-18871-S41475955232000123000000) table.
4. Connect digital voltmeter between specified output terminals. See «O2 SENSOR 4-WIRE CONNECTOR TERMINAL IDENTIFICATION»(ref-18871-S41475955232000123000000) table. Repeatedly race engine and observe O2 sensor output voltage. If O2 sensor output voltage is not 0.6-1.0 volt, replace O2 sensor. O2 SENSOR 4-WIRE CONNECTOR TERMINAL IDENTIFICATION Application Heater Terminals Output Terminals Mirage 1.6L 3 & 4 1 & 2

POWER STEERING OIL PRESSURE SWITCH

1. Power steering oil pressure switch is mounted on power steering pump. Disconnect single-wire connector at switch. Start engine.
2. Connect ohmmeter between switch terminal and ground. If continuity is present with steering wheel in straight-ahead position, replace switch. If continuity is not present while turning steering wheel, perform «POWER STEERING IDLE-UP SYSTEM TEST»(ref-18871-S29000335352000123000000) . See «IDLE-UP SYSTEMS»(ref-18871-S38737317642000123000000) under IDLE CONTROL SYSTEM.

Scheme 27

1. TPS is mounted to throttle body, at end of throttle shaft. Disconnect TPS connector. (Scheme 27) Using ohmmeter, measure total resistance between specified TPS connector terminals. See «TPS CONNECTOR TERMINAL IDENTIFICATION»(ref-18871-S01036382272000123000000) table. If resistance is not 3500-6500 ohms, replace TPS.
2. Using an analog (needle-type) ohmmeter, measure variable resistance between specified TPS connector terminals. See «TPS CONNECTOR TERMINAL IDENTIFICATION»(ref-18871-S01036382272000123000000) table.
3. Operate throttle valve from closed to wide open throttle. If resistance does not change smoothly within 3500-6500 ohms throughout throttle valve movement range, replace TPS. TPS CONNECTOR TERMINAL IDENTIFICATION Application Terminal No. Total Resistance 1 & 4 Variable Resistance 2 & 4

Scheme 28

1. Vehicle Speed Sensor (VSS) is located in speedometer assembly. Connect an ohmmeter between sensor test terminals on back of instrument panel. (Scheme 28)
2. Rotate speedometer cable. For each revolution of speedometer cable, sensor should make and break continuity 4 times. If ohmmeter reading does not fluctuate between continuity and no continuity or if sensor does not make and break continuity 4 times per revolution, replace sensor.

ISC Motor

See IDLE CONTROL SYSTEM .

RELAYS

Note. For internal wiring diagram of MPI control relay, see WIRING DIAGRAMS article.

MPI CONTROL RELAY LOCATION

Scheme 29

1. For relay location, see «MPI CONTROL RELAY LOCATION»(ref-18871-S33094409862000123000000) table. Check for battery voltage at terminal No. 10 of relay connector. (Scheme 29) If battery voltage is present, go to step 3). If battery voltage is not present, check circuit between relay and battery, including fusible link No. 1. Go to next step.
2. Apply battery voltage to terminal No. 10. Battery voltage should not be present at terminals No. 4 and 5. Apply battery voltage to terminal No. 10, and ground terminal No. 8. Battery voltage should now be present at terminals No. 4 and 5.
3. Apply battery voltage to terminal No. 3. Battery voltage should not be present at terminal No. 2. Apply battery voltage to terminal No. 3, and ground terminal No. 7. Battery voltage should now be present at terminal No. 2.
4. Apply battery voltage to terminal No. 9. Battery voltage should not be present at terminal No. 2. Apply battery voltage to terminal No. 9, and ground terminal No. 6. Battery voltage should now be present at terminal No. 2. Replace relay if it does not test as specified.

Scheme 30

1. For relay location, see «MPI CONTROL RELAY LOCATION»(ref-18871-S33094409862000123000000) table. Check for battery voltage at terminal No. 4 of relay connector. (Scheme 30) If battery voltage is present, go to step 3). If battery voltage is not present, check circuit between relay and battery, including fusible link No. 1. Go to next step.
2. Disconnect wiring harness connector at relay. Remove relay. Check continuity, in turn, between terminal No. 4 and following: terminals No. 1, 2 and 3. If there is no continuity, go to next step. If there is continuity, replace relay.
3. Check diode operation between terminals No. 6 and 8. If there is continuity in only one direction, go to next step. If there is no continuity in either direction or if there is continuity in both directions, replace relay.
4. Measure resistance between terminals No. 6 and 7. If resistance is approximately 35 ohms, go to next step. If resistance is not approximately 35 ohms, replace relay.
5. Measure resistance, in turn, between terminal No. 5 and following: terminals No. 2 and 3. In both tests, if resistance is approximately 95 ohms, go to next step. If resistance is not approximately 95 ohms, replace relay.
6. Connect positive lead of 12-volt source to terminal No. 7 and negative lead to terminal No. 6. If there is continuity between terminals No. 1 and 4, go to next step. If there is no continuity, replace relay.
7. Connect positive lead of 12-volt source to terminal No. 5 and negative lead to terminal No. 2. If there is continuity between terminals No. 1 and 4, go to next step. If there is no continuity, replace relay.
8. Connect positive lead of 12-volt source to terminal No. 5 and negative lead to terminal No. 3. If there is continuity between terminals No. 1 and 4, go to next step. If there is no continuity, replace relay.
9. Connect positive lead of 12-volt source to terminal No. 8 and negative lead to terminal No. 6. Check continuity, in turn, between terminal No. 4 and following: terminals No. 3 and 2. If continuity exists, relay is okay. If there is no continuity, replace relay.

Fuel Injector Solenoids

See FUEL CONTROL under FUEL SYSTEM.

FUEL DELIVERY

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

Fuel Injectors

1. Using a stethoscope, check operating sound of injector(s) during engine cranking or idling. If clicking sound is heard, injectors are okay. If clicking sound is not heard at each injector, go to step 2).
2. Disconnect injector electrical connector. Measure resistance between injector connector terminals. At 68°F (20°C), if resistance is not 13-16 ohms, replace injector.
3. If resistance is within specification, check injector wiring circuit for open or short to ground. If wiring circuit tests okay, replace injector.

1.5L

Connect 6-volt source across terminals No. 1 and 2 of ISC motor connector. (Scheme 31) Reverse leads of 6-volt source. If motor does not operate in both directions, replace ISC motor assembly.

Scheme 31

Scheme 32

1. Remove throttle body from intake plenum. Remove ISC motor from throttle body. Apply 6-volt source parallel to terminals No. 2 and 5 of ISC motor connector. (Scheme 32)
2. Apply source ground lead to ISC motor connector terminals No. 3 and 6. Note slight movement of ISC motor plunger. Remove ground leads from terminals No. 3 and 6.
3. Apply and remove source ground at terminals No. 1 and 6, 1 and 4, 3 and 4, and 3 and 6. Note slight movement of ISC motor plunger during each phase of test.
4. Beginning at terminal No. 6, reverse grounding sequence specified in steps 2) and 3). If motor does not operate when grounding any of specified terminals, replace ISC motor.

Disconnect ISC motor connector. Connect ohmmeter between terminals No. 1 and 2 of ISC motor connector. (Scheme 31) If resistance is not 5-35 ohms at 68°F (20°C), replace ISC motor assembly.

1.6L

Measure resistance between terminals No. 1 and 2, 2 and 3, 4 and 5, and 5 and 6 of ISC motor connector. (Scheme 32) In each case, if resistance is not 28-33 ohms at 68°F (20°C), replace ISC motor assembly.

Scheme 33

1. Disconnect pressure hose from power steering pump. Connect, in line, a pressure gauge and hoses capable of handling 300 psi (21 kg/cm 2 ). Also connect a shutoff valve in line with pressure gauge. (Scheme 33)
2. Bleed air from system by disabling ignition system and cranking engine while turning steering wheel completely from left to right several times. Start engine, and turn steering wheel back and forth to raise fluid temperature to approximately 122-140°F (50-60°C).
3. With engine idling, gradually close shutoff valve of pressure gauge to increase hydraulic pressure. If idle speed does not increase 200-250 RPM when fluid pressure reaches 213-284 psi (15-20 kg/cm 2 ), replace power steering idle-up switch.
4. Gradually open shutoff valve. If engine speed does not return to curb idle speed between 100-142 psi (7-10 kg/cm 2 ), replace power steering idle-up switch. Remove testing equipment. Bleed air from system as described in step 2).

IGNITION SYSTEM

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

Crank angle sensor is located inside distributor on SOHC engines. Sensor is attached to cylinder head on DOHC engines. If malfunction occurs, Code 22 will set. For testing procedure, see TESTS W/CODES article.

EGR Control Solenoid Valve (California)

1. EGR Control Solenoid Valve is located on center of firewall. Label and disconnect vacuum hoses and wiring harness from solenoid valve.
2. Connect hand vacuum pump to vacuum nipple where Green-striped vacuum hose was connected. Apply vacuum and ensure vacuum does not hold. Apply battery voltage to one terminal of solenoid, and ground other. Ensure vacuum holds.
3. Using an ohmmeter, measure resistance between terminals of solenoid valve. At room temperature, reading should be 36-44 ohms. Replace solenoid if resistance is not to specification.

Note. EGR temperature sensor only determines if EGR is operating. An inoperative sensor will not affect driveability or exhaust emissions.

1. Remove EGR temperature sensor from EGR valve. Place EGR temperature sensor in water. While increasing water temperature, measure resistance between wire terminals.
2. At a temperature of 122°F (50°C), resistance should be 60,000-80,000 ohms. At 212°F (100°C), resistance should be 11,000-14,000 ohms. Replace EGR temperature sensor if resistance differs significantly from specification.

EGR Thermovalve (1.6L Federal)

1. EGR Thrermovalve is locate below thermostat housing. Disconnect vacuum hoses from thermovalve, and connect a hand vacuum pump to a nipple of thermovalve.
2. With coolant temperature at 122°F (50°C) or less, ensure vacuum does not hold. At 176°F (80°C) or more, ensure vacuum holds.

EGR Valve

1. Remove EGR valve. Check valve for sticking, carbon deposits and damage. Clean valve with solvent if necessary. Apply 19.8 in. Hg to valve diaphragm. If valve does not hold vacuum, replace valve.
2. Apply specified vacuum to valve diaphragm. See CLOSED IN. HG column in «EGR VALVE SPECIFICATIONS»(ref-18871-S14159754352000123000000) table. If valve begins to open before vacuum reaches specification, replace valve.
3. Apply specified vacuum to valve diaphragm. See OPEN IN. HG column in «EGR VALVE SPECIFICATIONS»(ref-18871-S14159754352000123000000) table. If valve is not completely open after vacuum has reached specification, replace valve. EGR VALVE SPECIFICATIONS Application Closed In. Hg Open In. Hg All Models 2.1 6.8

Purge Control Solenoid Valve

1. Purge Control Solenoid Valve is located on left center of firewall. Label and disconnect both vacuum hoses from solenoid valve. Disconnect electrical connector. Connect hand vacuum pump to solenoid valve nipple where Red-striped hose was connected. Apply vacuum to solenoid valve. Vacuum should hold.
2. Apply battery voltage to terminals of solenoid valve. Vacuum should bleed down when voltage is applied to terminals. Using an ohmmeter, check resistance across solenoid valve terminals. Reading should be 36-44 ohms at 68°F (20°C). If reading is not within specification, replace valve.

PCV Valve

Remove PCV valve, and insert thin screwdriver into threaded end of valve to ensure plunger moves.