Engine Controls - System/component Tests: Other Infiniti J30 I

Ground Circuits

1. Using an ohmmeter, check for continuity to ground on ECM terminals No. 10, 20, 50, 60, 107, 108 and 116. Resistance should be zero ohms. If resistance is not zero ohms, repair open to ground.
2. Using a DVOM, touch negative lead of voltmeter to a good ground. Using positive lead of voltmeter, backprobe each ground terminal at ECM connector. With vehicle running, voltmeter should indicate less than one volt. If voltmeter reading is greater than one volt, check for open, corrosion or loose connection on ground lead.

Power Circuits

1. Ensure ignition switch is in OFF position. Using a voltmeter, check for battery voltage between chassis ground and ECM terminal No. 58. see scheme 6 If battery voltage is not present, check fusible link and wiring. Fusible link also supplies power for fuel injectors.
2. Turn ignition switch to ON position. Using a voltmeter, check for battery voltage between chassis ground and ECM terminals No. 45, 49, 59 and 109. If battery voltage is not present, check fusible link and fuse "G". Turn ignition switch to OFF position. Battery voltage should be present for approximately 2-3 seconds at terminals No. 49, 59 and 109. If battery voltage is not as specified, check ECCS relay.
3. Connect voltmeter between chassis ground and ECM terminal No. 43. Turn ignition switch to START position. Battery voltage should be present only when ignition switch is in START position. If voltage is not present, check for blown fuse and defective ignition switch.

ENGINE SENSORS & SWITCHES

Note. Sensor resistance and/or voltage values (when available from manufacturer) can be found in SENSOR RANGE CHARTS article in the ENGINE PERFORMANCE Section.

Scheme 57

1. Ensure no dust or foreign material exists in hot wire air passage. Fold back MAF sensor harness connector boot. Turn ignition on. Connect negative lead of voltmeter to ground. Using positive lead, backprobe MAF sensor terminal "b". (Scheme 57) Voltmeter should read as specified. See MASS AIRFLOW SENSOR VOLTAGE SPECIFICATIONS table.
2. Start engine, and allow it to warm to operating temperature. Recheck voltage reading. Voltage should be as specified. See MASS AIRFLOW SENSOR VOLTAGE SPECIFICATIONS table. Faults in MAF sensor circuit should set a Code 12. If Code 12 is present, refer to TESTS W/CODES article in the ENGINE PERFORMANCE Section.

MASS AIRFLOW SENSOR VOLTAGE SPECIFICATIONS (1)

COOLANT TEMPERATURE SENSOR

Disconnect coolant temperature sensor connector. Measure resistance across sensor terminals. See COOLANT TEMPERATURE SENSOR RESISTANCE TEST table. Replace sensor if it is not within specifications.

COOLANT TEMPERATURE SENSOR RESISTANCE TEST (1)

CRANKSHAFT POSITION SENSOR

1. Crankshaft position sensor is a self-contained unit located on left front of engine. If a fault is present in crankshaft position sensor, Code 11 may set in ECM memory. If Code 11 is set, proceed to TESTS W/CODES article in the ENGINE PERFORMANCE Section.
2. To test crankshaft position sensor, remove crankshaft position sensor. Leave sensor wiring connected. Using a DVOM, touch negative lead to ground and positive lead to one-degree signal, then to 90/120-degree signal terminals of crankshaft position sensor. See CRANKSHAFT POSITION SENSOR SIGNAL HARNESS TERMINALS table. (Scheme 58)
3. Rotate sensor by hand. On DVOM, signals should fluctuate between 0-5 volts with sensor rotating. If signal is not present, replace crankshaft position sensor.

CRANKSHAFT POSITION SENSOR SIGNAL HARNESS TERMINALS

Scheme 58

HEATED OXYGEN SENSOR (HO2S)

1. Disconnect oxygen sensor harness connector. Start and run engine until warm. Using DVOM, check voltage signal on center ("b") terminal, on sensor side of connector. With engine running, voltmeter should indicate between 0.3-1.0 volt and continuously fluctuate.
2. If voltage is not as specified, replace oxygen sensor. Also see FEEDBACK SYSTEM under «FUEL CONTROL»(ref-17576-S24267582202000122900000) . Oxygen sensor may set diagnostic Code 33 (left sensor) or 53 (right sensor).

HEATED OXYGEN SENSOR HEATER

1. Disconnect oxygen sensor connector at sensor. Using ohmmeter, check resistance between 2 outside terminals ("a" and "c") on sensor side of connector.
2. Resistance should be 3-1000 ohms. If not within specification, replace oxygen sensor. DO NOT touch ohmmeter to center terminal of sensor, as damage to oxygen sensor may result.
3. Ensure oxygen sensor connector is disconnected. Turn ignition on. Using voltmeter, measure voltage at terminal "c" on harness side of connector. If battery voltage is not indicated, check for blown 10-amp fuse in passenger compartment fuse block. To check ground circuit, check for open in Red/Black wire between ECM and oxygen sensor.

EGR TEMPERATURE SENSOR (CALIFORNIA)

1. Measure resistance across sensor terminals. Place exhaust gas temperature sensor in container of water. Sensor resistance should decrease as temperature increases.
2. Heat water until boiling temperature of 212°F (100°C) has been obtained. Resistance at 212°F (100°C) should be 76,770-93,830 ohms. If a fault is present in exhaust temperature sensor circuit, a Code 35 may be set in ECM memory. If a Code 35 is set, proceed to TESTS W/CODES article in the ENGINE PERFORMANCE Section.

FUEL TEMPERATURE SENSOR

Disconnect temperature sensor connector. Measure resistance across sensor terminals. See FUEL TEMPERATURE SENSOR RESISTANCE TEST table.

FUEL TEMPERATURE SENSOR RESISTANCE TEST (1)

INHIBITOR SWITCH

Disconnect inhibitor switch harness connector. Using a DVOM, check for continuity between inhibitor switch terminals "a" and "b". (Scheme 59) Continuity should be present in Park only. Move DVOM test leads to terminals "a" and "f". Continuity should be present in Neutral only.

Scheme 59

KNOCK SENSOR

Using an ohmmeter capable of reading greater than 10-megohm, test for continuity between knock sensor terminal and chassis ground. If continuity exists, circuit is okay. If continuity does not exist, replace knock sensor. If a fault is present in detonation sensor circuit, a Code 34 will be set in ECM memory. If a Code 34 is set, proceed to TESTS W/CODES article in the ENGINE PERFORMANCE Section.

POWER STEERING PRESSURE SWITCH

Switch is attached to power steering high pressure hose. Disconnect switch connector. With engine idling and steering wheel in straight-ahead position, check continuity across switch terminals. Turn steering wheel quickly left or right. Resistance should change from infinite to zero ohms.

START SIGNAL

Backprobe ECM terminal No. 43 with positive lead of DVOM. see scheme 6 Connect negative lead to chassis ground. Turn ignition switch to START position, battery voltage should exist at ECM terminal. If battery voltage does not exist, check for open in wire between ignition switch and ECM. If wire is okay, replace ignition switch.

Scheme 60

1. Throttle position sensor and Closed Throttle Position (CTP) switch are a combined assembly located on side of throttle body. CTP switch connector is located on sensor; TPS connector is located on short harness connected to sensor. Warm engine to operating temperature.
2. Turn ignition off. Disconnect TPS at harness. Connect ohmmeter between terminals No. 4 and 5 on sensor side of harness. (Scheme 60)
3. Resistance should be approximately 1700 ohms with throttle closed. With throttle completely open, resistance should be approximately 10,500 ohms. If sensor does not respond as indicated, adjust TPS. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
4. As throttle angle is slowly changed, resistance should change smoothly, with no skips or sudden changes indicated on ohmmeter. If sensor does not respond as indicated, replace TPS.
5. Reconnect TPS harness connector. Disconnect CTP switch connector. Connect ohmmeter leads between terminals No. 2 and 3 of CTP switch. With throttle fully closed, continuity should be present. With throttle slightly open, continuity should not be present. If switch does not respond as indicated, replace assembly.
6. If CTP and TPS test okay, check for sensor signal at ECM. To test for sensor signal, backprobe ECM terminal No. 54. see scheme 6 With engine running at idle, voltage should be present. Voltage should not be present when accelerator pedal is depressed. If no signal voltage is present at ECM, check for voltage at sensor.

VEHICLE SPEED SENSOR

Raise and support rear on jack stands. Disconnect vehicle speed sensor connector at wheel. Using an ohmmeter, check continuity across speed sensor harness connectors while rotating one driving wheel. Resistance should fluctuate between zero and infinite ohms.

A/C Clutch Relay

See MISCELLANEOUS CONTROLS. ECCS, Fuel Pump & Ignition Coil Relays For relay location, see RELAY LOCATION & IDENTIFICATION table. With battery voltage and ground applied to terminals No. 1 and 2 of relay, continuity should exist between terminals No. 3 and 5. (Scheme 61)

RELAY LOCATION & IDENTIFICATION

Scheme 61

Auxiliary Air Control (AAC) Solenoid

See IDLE CONTROL SYSTEM .

EGRC-Solenoid Valve

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

Fuel Injector

See FUEL CONTROL under FUEL SYSTEM.

PRVR Control Solenoid Valve

See FUEL EVAPORATION under EMISSION SYSTEMS AND SUB-SYSTEMS.

Valve Timing Control Solenoid Valve

See MISCELLANEOUS CONTROLS .

Relieving Fuel Pressure

Remove fuel pump fuse, start engine and allow engine to run until it stalls due to lack of fuel. Crank engine an additional 2-3 times to verify all pressure has dissipated.

Fuel Pressure

For basic fuel pressure procedures and specifications, see FUEL PRESSURE under FUEL SYSTEM in BASIC TESTING article in the ENGINE PERFORMANCE Section.

Fuel Pressure Regulator

1. Relieve fuel pressure from system. Connect fuel pressure gauge in line between fuel filter and fuel rail. Remove vacuum hose from fuel pressure regulator and plug hose. Connect hand-held vacuum pump to pressure regulator. Start engine and let idle.
2. Gradually apply vacuum to regulator. Fuel pressure should decrease as vacuum increases. Compare values to FUEL PRESSURE table in BASIC TESTING article in the ENGINE PERFORMANCE Section. If results are unsatisfactory, replace fuel pressure regulator.

Fuel Pump

Remove fuel tank filler cap. Turn ignition on. Listen for fuel pump operating noise. If noise is not present, check fuel pump relay and wiring harness between relay and pump. Check fuel pump control module.

FUEL PUMP TERMINAL IDENTIFICATION

Fuel Pump Control Module

Start engine and warm to operating temperature. Using a DVOM, backprobe between Blue and Black wire terminals of fuel pump control module. Voltmeter should read 4.2 volts with engine idling, and zero volts at 1500 RPM.

Fuel Pump Relay

See RELAYS under RELAYS & SOLENOIDS.

Start signal from ignition switch is used for ECM control of fuel pump and PRVR control solenoid. See PIN VOLTAGE CHART S article in the ENGINE PERFORMANCE Section.

FUEL CONTROL

ECM controls fuel system based upon sensor input signals. See FUEL CONTROL SYSTEM INPUT SIGNALS table. If feedback system does not function properly, check input signals before replacing ECM.

FUEL CONTROL SYSTEM INPUT SIGNALS

Feedback System

1. Start engine, and warm it to operating temperature. Ensure idle speed and timing are adjusted to specification. Increase engine speed to about 2000 RPM for 2 minutes under no-load condition. Using a small screwdriver, turn diagnostic mode selector screw on ECM.
2. With mode selector screw turned fully clockwise for at least 2 seconds, inspection lights will begin to flash. Turn screw fully counterclockwise. This switches ECM to Mode II, which is used to monitor exhaust gas sensor feedback signals.
3. With engine speed at 2000 RPM for 2 minutes, LED should flash at least 5 times during a 10-second period. If sensor does not respond as indicated and no other faults which may affect air/fuel mixture are indicated by ECM self-diagnostic system, use a voltmeter to verify input signals to ECM are correct. If input signals are correct, replace oxygen sensor. If input signals are not correct, replace ECM.
4. Vehicle uses 2 oxygen sensors. When Mode II is first entered, left bank oxygen sensor is being monitored. To change to right bank monitoring (with engine running), turn diagnostic mode selector screw on ECM fully clockwise. Wait at least 2 seconds. Turn selector lever fully counterclockwise. Repeat step 2).

1. With engine idling, individually disconnect injector harness connectors. Each injector should produce an equal RPM drop.
2. With engine cranking or while manually rotating crankshaft position sensor (harness connected with ignition on), listen for clicking or feel for vibration, indicating injectors are triggering. If injectors are not triggering, check power and ground circuits and crankshaft position sensor signal to ECM.
3. Disconnect fuel injector connector. Using ohmmeter, check across injector terminals for 10-14 ohms resistance. If 10-14 ohms is not indicated, replace fuel injector.
4. Check for injector leaks by removing injector fuel rail. Keep fuel hose and all injectors connected to rail. Turn ignition on. DO NOT start engine. Observe injector tips for leakage. If injectors drip, replace faulty injectors.

See ENGINE SENSORS & SWITCHES .

IDLE CONTROL SYSTEM

Idle speed is controlled by ECM through IACV-AAC. Fast Idle Control Device (FICD) controls fast idle. ECM controls idle speed components based upon signals received from various input devices. If idle speed components test correctly but idle speed is not being regulated properly, check input signals to ECM. See IDLE SPEED SYSTEM INPUT SIGNALS table.

AIR REGULATOR

Start engine. Pinch off large air line going to regulator. When engine is cold, RPM should drop. When engine is warmed up, RPM should not change. Disconnect air regulator connector. Ensure resistance across regulator terminals is 70-80 ohms.

AUXILIARY AIR CONTROL (IACV-AAC) VALVE

1. Warm engine to operating temperature. Place transmission in Neutral. Ensure idle speed is within specification. If idle speed is not within specification, adjust it before proceeding. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section. If idle speed cannot be adjusted, check idle speed screw passage for blockage.
2. With engine idling at specified RPM, disconnect AAC solenoid connector. RPM should drop. If RPM drops, AAC is functioning correctly.
3. If RPM does not drop, turn ignition off. Disconnect electrical connector from AAC solenoid. Using ohmmeter, ensure resistance of solenoid windings is 10 ohms. Remove AAC valve, and check for plunger seizing or sticking. Check for broken tension spring. If no faults are found, check AAC power and ground circuits. Check ECM input signals used to control AAC solenoid.

FAST IDLE CONTROL DEVICE (FICD) SOLENOID

Disconnect FICD solenoid connector. Briefly apply ground and battery voltage to solenoid. Solenoid should click as it is energized. If solenoid does not click, remove FICD and check for seizing or sticking plunger. Check for broken tension spring.

Ignition Coil

See IGNITION CHECKS in BASIC TESTING article in the ENGINE PERFORMANCE Section.

Power Transistor

See IGNITION CHECKS in BASIC TESTING article in the ENGINE PERFORMANCE Section.

ECM depends upon crankshaft position sensor for RPM signals. ECM uses signals to determine triggering of power transistors and fuel injectors. See CRANKSHAFT POSITION SENSOR and SUB-CRANKSHAFT POSITION SENSOR under ENGINE SENSORS & SWITCHES .

Timing Advance System

ECM controls ignition timing advance based upon sensor input signals that reflect ignition timing needs. If timing problems are experienced, inspect input signals for proper operation

1. Battery Voltage
2. Closed Throttle Position Switch
3. Crankshaft Position Sensor
4. Engine (Coolant) Temperature
5. Ignition (START) Signal
6. Mass Airflow Sensor
7. Park/Neutral (Inhibitor) Switch. (Signal received from transmission control unit).
8. Power Steering Pressure Switch
9. Throttle Position Sensor
10. Vehicle Speed Sensor

To check input signals, see ENGINE SENSORS & SWITCHES or ECM pin voltage charts in PIN VOLTAGE CHARTS article in the ENGINE PERFORMANCE Section.

PAIR VALVE

Start engine, and bring it to full operating temperature. With engine at idle, PAIR should operate. Raise engine speed to greater than 2000 RPM, and then allow it to return to idle. PAIR should not operate during acceleration and should operate on deceleration. If PAIR does not operate as specified, check vacuum hoses and PAIRC-solenoid valve. See PAIRC-SOLENOID VALVE. If hoses and solenoid are okay, replace PAIR valve.

PAIRC-SOLENOID VALVE

1. Remove vacuum lines and electrical connector from solenoid. Remove solenoid from vehicle. Apply battery voltage to White/Green wire terminal of solenoid. Apply ground to Gray wire terminal of solenoid. Blow into vacuum port "B" on end of solenoid.
2. As battery voltage is applied, air should pass out of vacuum port "A". With power and ground removed from solenoid, air should pass out of port "C". Port "C" may be covered by a filter. (Scheme 63)

EXHAUST GAS RECIRCULATION (EGR)

ECM controls EGR through a EGR solenoid valve. ECM controls solenoid based upon input signals received from various input components. If EGR system components test okay and system fails to function properly due to ECM control of EGR solenoid, test input signals which ECM uses to determine control of EGR system. See EGR SYSTEM INPUT SIGNALS table.

EGR SYSTEM INPUT SIGNALS

EGR System Check

1. Warm engine to normal operating temperature. Disconnect vacuum line at EGR valve and connect vacuum gauge. Increase engine speed to 2000 RPM. Vacuum should be indicated on gauge.
2. If vacuum is not indicated, check backpressure transducer and EGRC-solenoid valve. If components are okay, use a DVOM to check voltage at ECM terminal No. 102. With engine idling, voltmeter should read zero volts. At 2000 RPM, voltmeter should indicate battery voltage. See EGR SYSTEM INPUT SIGNALS table. Also check EGRC-solenoid power supply and harness between ECM and EGRC-solenoid for opens or shorts.

EGR Backpressure Transducer

1. Remove vacuum and exhaust lines from EGR Backpressure Transducer (EGRC-BPT). Plug one upper vacuum port of transducer. Connect hand-held vacuum pump to remaining EGR vacuum port. (Scheme 62) Apply vacuum. Vacuum should not hold. If vacuum holds, replace transducer.
2. Blow into exhaust pressure port. Apply vacuum to EGR vacuum port again. Vacuum should hold only when air pressure is applied to transducer pressure port. If vacuum is not as specified, replace transducer.

Scheme 62

EGR Valve

1. With engine idling, disconnect EGR vacuum line. Apply vacuum to EGR valve. Engine speed should decrease or engine should stall. If engine does not respond in this manner, go to step 2). Vacuum should hold on gauge. If vacuum does not hold, replace EGR valve.
2. Manually compress EGR valve diaphragm from underside. If engine speed does not decrease or engine does not stall, remove EGR valve and inspect EGR passages for plugging. If engine speed decreases or engine stalls, replace EGR valve.

1. Remove vacuum lines and electrical connector from solenoid. Remove solenoid from vehicle. Using jumper wires, connect battery voltage and ground to appropriate terminal of solenoid. See EGRC-SOLENOID TERMINAL IDENTIFICATION table. Blow into vacuum port "B" on end of solenoid. EGRC-SOLENOID TERMINAL IDENTIFICATION Application Power Ground J30 Green/Yellow Red/Black
2. As battery voltage is applied, air should pass out of vacuum port "A". With power and ground removed from solenoid, air should pass out of port "C". Port "C" may be covered by a filter. (Scheme 63)

EGR Temperature Sensor

Check sensor resistance with sensor immersed in a coolant solution heated to 212°F (100°C). Resistance across sensor terminals should be 77,000-94,000 ohms. Resistance should also decrease in response to temperature increase. If resistance is not as indicated, replace sensor.

Scheme 63

Carbon Canister & Purge Control Valve

Remove hoses from canister. Blow through port "C" of canister. Air should pass freely out of bottom of canister. Blow through port "B" of canister. A low volume of air should pass into canister. Apply vacuum to port "A" of canister. Volume of air blown into port "B" should increase. (Scheme 64)

Scheme 64

1. Remove vacuum lines and electrical connector from solenoid. Remove solenoid from vehicle. Using jumper wires, connect battery voltage and ground to solenoid connector terminals. Blow into vacuum port "B" on end of solenoid.
2. As battery voltage is applied, air should pass out of vacuum port "A". With power and ground removed from solenoid, air should pass out of port "C". Port "C" may be covered by a filter. (Scheme 63)

Vacuum Relief Filler Cap

Wipe cap clean. Apply vacuum from tank side. Slight resistance should be felt and cap should make distinct clicking noises. As vacuum increases, resistance should decrease and clicking noise should go away. If valve is plugged or no resistance is felt, replace cap as an assembly.

POSITIVE CRANKCASE VENTILATION (PCV)

Run engine at idle. Remove ventilation hose from PCV valve; hissing noise should be heard and a strong vacuum should be felt immediately when finger is placed over valve inlet. If vacuum is not felt, check PCV valve for clogging. Service or replace as necessary.

MISCELLANEOUS CONTROLS

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

1. A/C clutch relay is controlled by ECM. Under normal conditions, ECM will engage clutch relay by providing a ground circuit for relay windings. If ECM receives a wide open throttle signal from throttle position sensor while it is also receiving a A/C on signal from A/C auto amplifier, ECM will disengage relay.
2. A/C clutch relay (Blue or Green) is located in relay box on right side of engine compartment. Relay is in right front corner of relay box.
3. Remove relay from relay box. Apply ground to terminal No. 2 of relay. see scheme 10 Apply battery voltage to terminal No. 1. With relay energized, continuity should exist between terminals No. 3 and 5. No continuity should exist with relay de-energized.

Remove solenoid from front of engine. Apply battery voltage across solenoid terminals. (Scheme 65) If solenoid does not energize, replace solenoid.

Scheme 65