Engine Controls - System/component Tests: Other Mitsubishi Diamante I

Turbocharger Pressure Check

1. Disconnect turbocharger pressure control hose at wastegate solenoid valve, and plug nipple. Attach pressure gauge to hose. Drive vehicle and accelerate engine, in 2nd gear, to 3500 RPM or greater. Measure turbocharger pressure when pressure gauge stabilizes. See «TURBOCHARGER PRESSURE SPECIFICATIONS»(ref-18918-S19062502882001010800000) table.
2. If pressure gauge reading is more than specified, check wastegate actuator. See «WASTEGATE ACTUATOR TEST»(ref-18918-S05258859192001010800000) . Replace wastegate actuator as required. If pressure gauge reading is less than specified, check for malfunctioning wastegate valve, turbocharger pressure leaks and faulty turbocharger. TURBOCHARGER PRESSURE SPECIFICATIONS Application Pressure psi (kg/cm 2 ) Stealth & 3000GT 2.9-8.7 (20-60)

Air By-Pass Valve

Remove air by-pass valve. Valve is mounted to intake air duct between air-to-air intercooler and intake plenum. Apply vacuum to diaphragm of vacuum valve. Valve should begin opening at approximately 16 in. Hg. Observe operation of valve through by-pass opening.

NON-TURBOCHARGED

Note. For diagnosis and testing information concerning VIC motor position sensor, see TESTS W/CODES article in this section.

Variable Induction Control (Stealth & 3000GT)

1. Disconnect Variable Induction Control (VIC) valve position sensor connector. Connect test harness (MB991348 ) between connector and control valve. Measure voltage between terminals No. 2 (Red/White wire) and No. 3 (Black wire). Measure voltage between terminals No. 3 and 4 (Black/Blue wire). Voltage should be 0-1 or 4.5-5.5 volts.
2. Disconnect VIC servo connector. Connect DVOM between both servo connector terminals to check servo coil resistance. Resistance should be 5-35 ohms. Replace servo if resistance is not as specified.
3. Apply 6 volts between both servo connector terminals. Ensure variable induction control servo shaft turns smoothly. Reverse voltage to servo connector terminals. Servo shaft should turn smoothly in opposite direction. If servo shaft does not function properly, replace air intake plenum assembly.
4. Check for continuity in circuit between control motor connector and ECM. Disconnect VIC motor connector and ECM connector. Connect DVOM to Green/Black wire of VIC connector and vehicle ground. Ground terminal No. 109 (Green/Black wire) of ECM. Check circuit for continuity. If continuity does not exist, repair as needed.
5. Connect DVOM to Green/White wire of VIC connector and vehicle ground. Ground terminal No. 110 (Green/White wire) of ECM. Check circuit for continuity. If continuity does not exist, repair as needed.

CONTROL UNIT

Note. For Engine Control Module (ECM) location, see ENGINE CONTROL MODULE (ECM) LOCATION table. To identify ECM power and ground circuits, see appropriate WIRING DIAGRAMS article in this section.

Ground Circuits

1. Turn ignition off. Using an ohmmeter, check continuity between chassis ground and ECM ground terminals. See «GROUND TERMINAL ID»(ref-18918-S35833833792001010800000) table. Ohmmeter should indicate zero ohms. If reading is not zero ohms, check and repair open circuit between ECM connector and ground.
2. Connect voltmeter negative lead to chassis ground. Connect positive lead to ECM ground terminals. See «GROUND TERMINAL ID»(ref-18918-S35833833792001010800000) table. (Scheme 43) 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.

Power Circuits

Turn ignition on. Check for battery voltage on ECM power terminals. See POWER TERMINAL ID table. If battery voltage is not present, check operation of MPI control relay. See RELAYS under MOTORS, RELAYS & SOLENOIDS.

Scheme 43

GROUND TERMINAL ID

POWER TERMINAL ID

ENGINE CONTROL MODULE (ECM) LOCATION

BAROMETRIC PRESSURE SENSOR

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

CAMSHAFT POSITION SENSOR

See TESTS W/CODES article in this section.

CLOSED THROTTLE POSITION SWITCH

See THROTTLE POSITION SENSOR in TESTS W/CODES article in this section.

COOLANT TEMPERATURE SENSOR

See TESTS W/CODES article in this section.

CRANKSHAFT POSITION SENSOR

See TESTS W/CODES article in this section.

EGR TEMPERATURE SENSOR (CALIFORNIA)

See TESTS W/CODES article in this section.

IDLE POSITION SWITCH

See THROTTLE POSITION SENSOR in TESTS W/CODES article in this section.

INHIBITOR SWITCH (A/T MODELS

1. Switch is mounted to automatic transaxle, near shift lever mechanism. Ensure switch is adjusted properly. Switch output can be affected by improper adjustment. Using DVOM, measure resistance between selected terminals to ensure continuity between ignition switch and ECM when shift selector lever is in Park or Neutral position. See «INHIBITOR SWITCH CONTINUITY CHECK»(ref-18918-S07579338302001010800000) table.
2. Using DVOM, measure power supply voltage of switch. Disconnect ECM connector. Disconnect inhibitor switch connector. Turn ignition switch to START position. Measure voltage between inhibitor switch and vehicle ground. On all models, inhibitor switch wire color is Black/Yellow. Supply voltage should be battery voltage. If voltage is within specification, go to step 3. If voltage is less than battery voltage, check and repair power supply circuit.
3. Using DVOM, measure inhibitor switch terminal input voltage. Connect ECM connector. Ensure inhibitor switch connector is disconnected. Turn ignition switch to ON position. Measure voltage between inhibitor switch and vehicle ground. Input voltage should be battery voltage. If voltage is within specification, go to step 4. If voltage is less than battery voltage, check and repair circuit.
4. Using DVOM, measure input voltage of ECM. Disconnect ECM connector. Connect inhibitor switch connector. Ensure shift selector lever is in "P" position. Turn ignition switch to ON position. Measure voltage between ECM connector and vehicle ground. See «ECM TERMINAL ID»(ref-18918-S13708519742001010800000) table. ECM input voltage should be 8 volts or greater. If voltage is within specification, system is okay. If voltage is less than 8 volts, replace ECM. INHIBITOR SWITCH CONTINUITY CHECK Application (1) Wire Color (2) Wire Color All Models Black/Yellow Black/Red (1) Ignition switch to inhibitor switch circuit. (2) Inhibitor switch to ECM circuit. ECM TERMINAL ID Application (1) Terminal Number All Models 71 (1) (Scheme 43)

INTAKE AIR TEMPERATURE SENSOR

See TESTS W/CODES article in this section.

OXYGEN (O2) SENSOR

See TESTS W/CODES article in this section.

POWER STEERING OIL PRESSURE SWITCH

1. Disconnect switch connector at pump. Using DVOM, check continuity between switch and vehicle ground. Continuity should not exist with wheels straight ahead and engine idling. Continuity should be present when wheels are turned.
2. Check continuity of circuit between switch and ECM. Disconnect power steering oil pressure switch connector and ECM connector. Connect jumper wire between ECM terminal and vehicle ground. See «POWER STEERING PRESSURE SWITCH ECM TERMINAL NUMBER»(ref-18918-S08862232962001010800000) table. Using DVOM, check for continuity between switch harness connector and vehicle ground. Check and repair circuit if no continuity exists. Go to step 3 if continuity exists.
3. Connect ECM connector. Turn ignition on. Using DVOM, measure voltage at switch harness connector. System is okay if battery voltage exists. Replace ECM if voltage does not exist. POWER STEERING PRESSURE SWITCH ECM TERMINAL NUMBER Application (1) Terminal Number All Models 107 (1) (Scheme 43)

THROTTLE POSITION SENSOR

See TESTS W/CODES article in this section.

VEHICLE SPEED SENSOR

See TESTS W/CODES article in this section.

IAC Motor

See IDLE CONTROL SYSTEM .

RELAYS

For MPI control relay location, see MPI CONTROL RELAY LOCATION table.

MPI CONTROL RELAY LOCATION

Scheme 44

1. This step checks ignition supply voltage to ECM. Disconnect ECM harness connector. Turn ignition on. Using DVOM, measure voltage between ECM harness connector terminal No. 62 and vehicle ground. (Scheme 43) If voltage measured is battery voltage, go to step 2. If voltage is not battery voltage, check and repair circuit between ignition switch and ECM harness connector.
2. This step checks battery supply voltage of control relay. Using DVOM, measure voltage between terminal No. 10 of relay harness connector and vehicle ground. (Scheme 44) If voltage measured is battery voltage, go to step 3. If voltage is not battery voltage, check and repair circuit between battery and control relay.
3. This step checks continuity of circuit between control relay and ECM. Disconnect ECM connector. Using DVOM, check continuity between control relay harness connector terminal No. 8 and ECM harness connector terminal No. 108. If continuity exists, go to step 4. If continuity does not exist, check and repair circuits between control relay harness connector and ECM.
4. This step checks continuity of circuit between control relay and ECM. Check continuity between control relay harness connector terminal No. 4 and ECM harness connector terminals No. 12 and 25. If continuity exists, go to step 5. If continuity does not exist, check and repair circuits between control relay harness connector and ECM.
5. This step checks supply voltage to control relay actuator. Connect ECM and MPI control relay connectors. Using DVOM, backprobe control relay terminal No. 5. With engine cranking, voltage should be 8 volts or greater. Start engine and run at 2500 RPM or greater. If voltage is battery voltage, harness is okay. If voltage is not battery voltage, go to step 6.
6. If control relay tests okay in steps 6 through 8, replace ECM. Connect 12-volt power source between relay terminals No. 8 and 10. Connect positive lead to terminal No. 10. With relay energized, battery voltage should exist between terminals No. 4 and 8 and between terminals No. 5 and 8. With power source removed, voltage should not exist.
7. Move 12-volt power source to relay terminals No. 6 and 9. Connect positive lead to terminal No. 9. With relay energized, continuity should exist between terminals No. 2 and 3. With power source removed, continuity should not exist.
8. Move 12-volt power source to relay terminals No. 3 and 7. Connect positive lead to terminal No. 3. With relay energized, battery voltage should exist between terminals No. 2 and 7. With power source removed, voltage should not exist. Replace control relay if any measurements are not as specified.

Fuel Pressure Regulator Control Solenoid Valve (Turbo Models)

See FUEL DELIVERY under FUEL SYSTEM.

Wastegate Control Solenoid Valve

See TURBOCHARGED under AIR INDUCTION SYSTEMS.

FUEL DELIVERY

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

Fuel Pressure Regulator Control Solenoid Valve (Turbo)

1. Label and remove vacuum hoses from solenoid valve. Disconnect wiring harness. Connect vacuum pump to nipple where Black vacuum hose was connected. Leave pump connected throughout procedure.
2. Apply vacuum and ensure valve leaks. Plug nipple where Blue-striped hose was connected. Apply vacuum and ensure vacuum holds. Remove plug from Blue-striped hose nipple. Apply battery voltage across valve terminals. Apply vacuum and ensure vacuum holds.
3. Using an ohmmeter, check resistance across terminals of solenoid. Resistance should be 36-46 ohms at 68°F (20°C). If resistance is not within specification, replace valve.
4. If resistance is within specification, disconnect solenoid connector. Turn ignition on. Using DVOM, measure voltage between harness connector terminal (Red wire) and vehicle ground. If voltage is battery voltage, go to step 5. If voltage is not battery voltage, check and repair circuit between MPI control relay and solenoid.
5. This step checks continuity of circuit between solenoid and ECM. Disconnect ECM connector. Connect jumper wire between ECM terminal No. 7 and vehicle ground. (Scheme 43) Using DVOM, measure continuity between solenoid harness connector terminal Blue/Red wire and vehicle ground. If continuity exists, system is okay. If continuity does not exist, check and repair circuit between solenoid and ECM.

Fuel Injectors

See TESTS W/CODES article in this section.

DOHC

1. Disconnect ECM connector. Using DVOM, measure input voltage between terminal No. 24 (Red/Green wire) and vehicle ground. Turn headlights on. Measure voltage. Turn headlights off.
2. Turn defogger on. Measure voltage. Turn defogger off. Depress brake pedal. Measure voltage. Release brake pedal. If any measurement is less than battery voltage, check and repair malfunctioning circuit.

IDLE AIR CONTROL (IAC) MOTOR

Note. For diagnosis and testing information concerning IAC motor position sensor, see TESTS W/CODES article in this section.

Note. Procedures are provided by manufacturer for component testing using an engine analyzer with oscilloscope capability. Refer to manufacturer's operation manual for instructions in use of oscilloscope. Go to step 10 for test procedures using oscilloscope.

Scheme 45

Scheme 46

1. Using a stethoscope, listen for operating sound of IAC motor when ignition switch is placed in ON position. If no operating sound can be heard, proceed with following tests.
2. Disconnect IAC harness connector. Install Test Harness (MD998463-01 ) if necessary to aid testing. Using DVOM, measure resistance between IAC terminals No. 1 and 2 and between terminals No. 1 and 3. (Scheme 45) Resistance should be 28-33 ohms.
3. Measure resistance between terminals No. 4 and 5 and between terminals No. 5 and 6. Resistance should be 28-33 ohms. If resistance measurements are not within specification, replace IAC motor. Go to step 4 if IAC motor is within specification.
4. Remove throttle body. See «N - REMOVE/INSTALL/OHAUL»(ref-19020) article in this section. Remove stepper motor from throttle body. Connect Test Harness (MD998463-01 ) to IAC motor.
5. Hold IAC motor in hand. Place thumb on top of plunger. Connect positive lead of 6-volt power source to White and Green clips of test harness. Individually connect, then disconnect, negative lead of power source to Red and Black clips, Blue and Black clips, Blue and Yellow clips, and Red and Yellow clips. Finish by connecting negative lead to Red and Black clips again.
6. Connect negative lead to test leads in reverse sequence of step 5. Stepper motor should vibrate with each connection. Replace IAC motor if vibration is not felt with each connection.
7. Ensure MPI control relay is functioning properly. See «RELAYS»(ref-18918-S39445204252001010800000) under MOTORS, RELAYS & SOLENOIDS. Disconnect IAC motor harness connector. Turn ignition on. Using DVOM, check for battery voltage between terminal No. 2 and vehicle ground and terminal No. 5 and vehicle ground. If voltage is not battery voltage, check and repair circuits between MPI control relay and IAC motor. If battery voltage exists, go to step 8.
8. This step checks for continuity between MPI control relay and IAC motor. Check for continuity between MPI control relay terminals No. 4 and 5 and IAC motor terminals No. 2 and 5. (Scheme 44)and (Scheme 45). If continuity exists, go to step 9. If continuity does not exist, check and repair circuits.
9. This step checks for continuity between ECM and IAC motor. Disconnect ECM harness connector. Check continuity of specified circuits. (Scheme 43)and (Scheme 45). See «IAC TO ECM CIRCUIT CONTINUITY CHECK»(ref-18918-S39975366862001010800000) table. Check and repair any circuits without continuity. IAC TO ECM CIRCUIT CONTINUITY CHECK IAC Terminal Number ECM Terminal Number 1 4 3 17 4 5 6 18
10. Connect ECM harness connector. Install harness connector and Test Harness (MB998463-01 ). Using engine analyzer with oscilloscope capability, connect special patterns probe to selected leads of test harness. Leads used are Red, Green, Black and Yellow clips.
11. Start engine, and allow it to idle. Connect special patterns probe to one test lead. Turn A/C on. When IAC motor operates to increase engine speed to compensate for A/C system, a waveform should be displayed. Conduct test with each remaining test lead and compare pattern to illustration. (Scheme 46)
12. If waveform is different, replace IAC motor. If all preceding tests do not show any system or component malfunction and ECM is suspected, replace ECM and retest system.

IDLE SPEED CONTROL MOTOR

Note. For diagnosis and testing information concerning ISC motor position sensor, see TESTS W/CODES article in this section.

IGNITION SYSTEM

Note. For basic ignition checks, see BASIC TESTING article in this section.

See TESTS W/CODES article in this section.

See TESTS W/CODES article in this section.

Knock Sensor

See TESTS W/CODES article in this section.

EXHAUST GAS RECIRCULATION (EGR)

See TESTS W/CODES article in this section.

Purge Control Solenoid Valve

1. 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.
3. This step checks voltage at purge solenoid. Disconnect purge solenoid harness connector. Turn ignition on. Using DVOM, measure voltage at harness connector terminal No. 1 (horizontal terminal). If voltage is battery voltage, go to step 4. If voltage is not battery voltage, check and repair circuit between purge solenoid and MPI control relay.
4. This step checks continuity between ECM and purge solenoid. Disconnect ECM harness connector. Connect jumper wire between ECM terminal No. 9 and vehicle ground.
5. Using DVOM, check for continuity between purge solenoid harness connector terminal No. 2 (vertical terminal) and vehicle ground. If continuity exists, harness is good. If continuity does not exist, check and repair circuit.
6. If preceding tests do not show any system or component malfunction and ECM is suspected, replace ECM and retest system. ECM TERMINAL ID Application Terminal Number All Models 9

PCV Valve

Remove PCV valve. Shake valve by hand. Valve should rattle if moving freely. Apply air pressure to valve. Air should flow in one direction only. Connect PCV valve to vacuum hose and start engine. Ensure vacuum is flowing through valve.

MISCELLANEOUS CONTROLS

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

Accelerator Pedal Position Sensor(Diamante With Traction Control)

1. Sensor is connected to throttle valve. Disconnect sensor connector. Measure resistance between terminals No. 1 (Black wire) and No. 4 (Green/Yellow wire). Resistance should be 3.5-6.5 ohms.
2. Using analog ohmmeter, measure resistance between terminals No. 1 (Black wire) and No. 3 (Yellow/Red wire). Monitor ohmmeter while slowly opening throttle from idle position to WOT. Resistance should change smoothly in proportion with throttle opening. Replace sensor if ohmmeter displays erratic changes in resistance when opening throttle.
3. Check for open or short in circuit between accelerator pedal position sensor and ECM. Disconnect sensor and ECM connectors. Connect ohmmeter between sensor connector terminal No. 4 (Green/Yellow wire) and vehicle ground. Ground ECM connector terminal No. 61 (Green/Yellow wire). Repair circuit as needed if continuity does not exist.
4. Check for continuity between sensor connector terminal No. 1 (Black wire) and vehicle ground. Repair circuit between sensor connector terminal No. 1 and ECM connector No. 72 as needed if continuity does not exist. Connect ECM connector. Turn ignition on. Using DVOM, measure voltage between sensor connector terminal No. 4 (Green/Yellow wire) and vehicle ground. Voltage should be 4.8-5.2 volts. Replace ECM is voltage is not within specification.

A/C Switch & Compressor Clutch Relay

Using DVOM, measure power supply voltage of ECM. Disconnect ECM connector. Turn A/C switch and ignition switch to ON positions. Measure voltage between specified ECM terminals and vehicle ground. See A/C POWER ECM TERMINAL LOCATION table. Voltage should be 6 volts or greater. If voltage is not battery voltage, check and repair circuit.

A/C POWER ECM TERMINAL LOCATION