Engine Controls - System/component Tests: Other Infiniti Q45 II

Ground Circuits (I30)

1. Using a DVOM, measure resistance between ground and PCM terminals No. 10, 19, 25, 32, 108, 116 and 124 by backprobing. (Scheme 57) Resistance should be zero ohms at all terminals. If resistance is as specified, go to next step. If resistance is not as specified, repair open or poor connection in appropriate circuit.
2. Using a DVOM, connect negative lead of DVOM to a good ground. Using positive lead of DVOM, backprobe at PCM terminals No. 10, 19, 25, 32, 108, 116 and 124. With vehicle running, DVOM should indicate less than one volt at all terminals. If voltage is as specified, ground circuits are okay at this time. If voltage is not as specified, repair short to voltage in appropriate circuit.

Power Circuits (I30)

1. Turn ignition switch to RUN position. Using a DVOM, check for battery voltage between ground and PCM terminals No. 4, 24, 67 and 72 by backprobing. (Scheme 57) If battery voltage is present at all terminals, go to next step. If battery voltage is not present at all terminals, check fusible link, fuse "G" and wiring. Repair as necessary.
2. Turn ignition switch to OFF position. Using a DVOM, check for battery voltage between ground and PCM terminal No. 80 (power back-up) by backprobing. If battery voltage is not present, check for overheated relays, fusible links and wiring. Repair as necessary

Ground Circuits (Q45)

1. Using a DVOM, measure resistance between ground and PCM terminals No. 121, 122, 125, 126, 127and 128 by backprobing. (Scheme 58) Resistance should be zero ohms at all terminals. If resistance is as specified, go to next step. If resistance is not as specified, repair open or poor connection in appropriate circuit.
2. Using a DVOM, connect negative lead of DVOM to a good ground. Using positive lead of DVOM, backprobe at PCM terminals No. 121, 122, 125, 126, 127 and 128. With vehicle running, DVOM should indicate less than one volt at all terminals. If voltage is as specified, ground circuits are okay at this time. If voltage is not as specified, repair short to voltage in appropriate circuit.

Power Circuits (Q45)

1. Turn ignition switch to RUN position. Using a DVOM, check for battery voltage between ground and PCM terminals No. 56, 130 and 131. (Scheme 58) If battery voltage is present at all terminals, go to next step. If battery voltage is not present at all terminals, check fusible link, fuse "G" and wiring. Repair as necessary.
2. Turn ignition switch to OFF position. Using a DVOM, check for battery voltage between ground and PCM terminal No. 78 (power back-up). If battery voltage is present, power circuits are okay at this time. If battery voltage is not present, check for overheated relays, fusible links and wiring.

Scheme 57

Scheme 58

ENGINE SENSORS & SWITCHES

Note. Sensor resistance and/or voltage values (when available) can be found in SENSOR RANGE CHARTS article.

Note. For system testing of sensors and switches, see appropriate TESTS W/CODES articles below

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

CRANKSHAFT POSITION (CKP) SENSOR

See DTC P0335: CRANKSHAFT POSITION (CKP) SENSOR in appropriate TESTS W/CODES articles below

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

CAMSHAFT POSITION (CMP) SENSOR

See DTC P0340: CAMSHAFT POSITION (CMP) SENSOR in appropriate TESTS W/CODES articles below

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

Disconnect ECT sensor harness connector. Using a DVOM, measure resistance between ECT sensor terminals. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR table.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

EGR TEMPERATURE SENSOR

See EMISSION SYSTEMS & SUB-SYSTEMS .

IGNITION SWITCH (START SIGNAL)

Backprobe PCM terminal No. 20 with positive lead of DVOM. (Scheme 57)or (Scheme 58). Connect negative lead to ground. Turn ignition switch to START position and battery voltage should exist. If battery voltage does not exist, check for open in wire between ignition switch and PCM. See WIRING DIAGRAMS. If wire is okay, replace ignition switch.

INTAKE AIR TEMPERATURE (IAT) SENSOR

Disconnect ECT sensor harness connector. Measure resistance between IAT sensor terminals. Readings should be as follows

1. At 68°F (20°C), resistance should be 2100-2900 ohms.
2. At 176°F (80°C), resistance should be 270-380 ohms.

FRONT HEATED OXYGEN SENSOR (HO2S)

See appropriate DTC for FRONT HEATED OXYGEN SENSOR (HO2S) in appropriate TESTS W/CODES articles below. Refer to DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION (I30/Q45) table in TESTS W/CODES - INTRODUCTION article.

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

REAR HEATED OXYGEN SENSOR (HO2S)

See appropriate DTC for REAR HEATED OXYGEN SENSOR (HO2S) in appropriate TESTS W/CODES articles below. Refer to DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION (I30/Q45) table in TESTS W/CODES - INTRODUCTION article.

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

KNOCK SENSOR (KS)

See DTC P0325: KNOCK SENSOR (KS) in TESTS W/CODES articles below

1. For I30, see «TESTS W/CODES»(ref-18055) article.
2. For Q45, see «TESTS W/CODES»(ref-18056) article.

MASS AIRFLOW (MAF) SENSOR

See DTC P0100: MASS AIRFLOW (MAF) SENSOR in TESTS W/CODES articles below

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

POWER STEERING PRESSURE SWITCH

Switch is attached to power steering high pressure hose. Disconnect power steering pressure switch harness connector. With engine idling and steering wheel in straight-ahead position, check continuity between switch terminals. While observing DVOM, turn steering wheel quickly left or right. Continuity should exist during turn.

TANK FUEL TEMPERATURE SENSOR

See DTC P0180: TANK FUEL TEMPERATURE SENSOR in TESTS W/CODES articles below. Throttle Position (TP) Sensor - See DTC P0120: THROTTLE POSITION (TP) SENSOR.

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

VEHICLE SPEED SENSOR (VSS)

See DTC P0500: VEHICLE SPEED SENSOR (VSS) in appropriate TESTS W/CODES articles below.

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

A/C Clutch Relay

See MISCELLANEOUS CONTROLS .

ECCS, Fuel Pump & Ignition Coil Relays

1. Two types of relays are used; 4-terminal and 6-terminal. For relay location, see «RELAY LOCATION & IDENTIFICATION»(ref-18057-S22839110892000122900000) table. Remove appropriate relay. Apply battery voltage and ground to terminals No. 1 and 2. (Scheme 59), (Scheme 60), (Scheme 61) or (Scheme 62).
2. On 4-terminal relays, continuity should exist between terminals No. 3 and 5. On 6-terminal relays, continuity should exist between terminals No. 3, 5, 6 and 7. When battery voltage is removed, continuity should not exist. Replace relay if test values are not as specified.

Park/Neutral Relay (Q45)

See DTC P0705: PARK/NEUTRAL POSITION SWITCH in TESTS W/CODES articles below

1. For I30, see «TESTS W/CODES»(ref-18055) article.
2. For Q45, see «TESTS W/CODES»(ref-18056) article.

RELAY LOCATION & IDENTIFICATION

Scheme 59

Scheme 60

Scheme 61

Scheme 62

SOLENOIDS

Note. For EGR and EVAP system components, see EMISSION SYSTEMS & SUB-SYSTEMS.

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.

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»(ref-18054) article. If results are not as specified, replace fuel pressure regulator.

Fuel Pump

1. Remove fuel tank filler cap. Turn ignition switch to RUN position. Listen for fuel pump operating noise. If noise is not present, check fuel pump relay and wiring harness between relay and pump. If no faults are found, check Fuel Pump Control Module (FPCM). See DTC P1220: FUEL PUMP CONTROL MODULE (FPCM) in appropriate TESTS W/CODES articles below. For I30 see «TESTS W/CODES»(ref-18055) For Q45 see «TESTS W/CODES»(ref-18056)
2. On all models, if FPCM is okay, disconnect fuel pump/sending unit harness connector at fuel tank. On I30, check resistance across fuel pump terminals. On Q45, check resistance between terminals No. 1 and 3. (Scheme 63) On all models, at 68°F (20°C) reading should indicate less than 5 ohms. If resistance is not correct, replace fuel pump.

Scheme 63

Fuel Pump Control System (I30)

1. Remove fuel pump relay. (Scheme 64) Turn ignition switch to RUN position. Check for battery voltage between ground and fuel pump relay harness connector terminal No. 1 (Brown wire) and terminal No. 3 (Black/White wire). If battery voltage is present, go to next step. If battery voltage is not present, check wiring connectors, fuse No. 17 (10-amp) and fuse No. 32 (15-amp) in fuse box.
2. Turn ignition switch to LOCK position. Disconnect fuel pump. Disconnect dropping resistor harness connector. (Scheme 65) Check continuity as follows: Between dropping resistor harness connector terminal No. 1 (Green/Red wire) and fuel pump harness connector terminal No. 2 (Green/Red wire). Between fuel pump harness connector terminal No. 1 (Black/Yellow wire) and fuel pump relay harness connector terminal No. 5 (Black/Yellow wire). Between ground and dropping resistor harness connector terminal No. 2 (Black wire). If continuity exists, go to next step. If continuity does not exists, repair fault in appropriate circuit.
3. Leave ignition off. Disconnect PCM harness connector. Check continuity between fuel pump relay harness connector terminal No. 2 (Black/Pink wire) and PCM harness connector terminal No. 11 (Black/Pink wire). If continuity does not exists, repair fault in circuit. If continuity exists, check fuel pump. If fuel pump is okay, test fuel pump relay. See «RELAYS»(ref-18057-S28096613722000122900000) under RELAYS & SOLENOIDS.

Scheme 64

Scheme 65

Fuel Pump Control System (Q45)

1. Remove fuel pump relay. (Scheme 66) Turn ignition switch to RUN position. Check for battery voltage between ground and fuel pump relay harness connector terminals No. 1 (White wire) and No. 3 (Black/White wire). If battery voltage is present, go to next step. If battery voltage is not present, check wiring connectors, fuses No. 29 (15-amp) and No. 33 (15-amp) in fuse box.
2. Turn ignition switch to LOCK position. Disconnect fuel pump. Disconnect dropping resistor harness connector, located in luggage compartment. (Scheme 67) Check continuity as follows: (Scheme 68) Between dropping resistor harness connector terminal No. 1 (Green/Red wire) and fuel pump harness connector terminal No. 3 (Green/Red wire). Between fuel pump harness connector terminal No. 1 (Black/Yellow wire) and fuel pump relay harness connector terminal No. 5 (Black/Yellow wire). Between ground and dropping resistor harness connector terminal No. 2 (Black wire).

If continuity exists, go to next step. If continuity does not exists, repair fault in appropriate circuit.

3) Leave ignition switch in LOCK position. Disconnect PCM harness connector. Check continuity between fuel pump relay harness connector terminal No. 2 (Black/Pink wire) and PCM harness connector terminal No. 11 (Black/Pink wire). If continuity does not exists, repair fault in circuit. If continuity exists, check fuel pump. If fuel pump is okay, test fuel pump relay. See RELAYS under RELAYS & SOLENOIDS.

Fuel Pump Control Module (FPCM)

See DTC P1220: FUEL PUMP CONTROL MODULE (FPCM) in TESTS W/CODES articles below

1. For I30, see «TESTS W/CODES»(ref-18055) article.
2. For Q45, see «TESTS W/CODES»(ref-18056) article.

Fuel Pump Relay

See RELAYS under RELAYS & SOLENOIDS.

Scheme 66

Scheme 67

Scheme 68

FUEL CONTROL

PCM controls fuel system by varying fuel injector pulse width and duration based upon sensor input signals. If feedback system does not function properly, check A/C clutch signal, battery voltage, closed throttle position switch, Crankshaft Position Sensor (CKP), EGR temperature sensor, Engine Coolant Temperature (ECT), Heated Oxygen Sensors (HO2S), ignition (START) signal, Mass Airflow (MAF) sensor, park/neutral switch, power steering pressure switch, secondary throttle sensor, sub-crankshaft position sensor, Throttle Position (TP) sensor, Vehicle Speed Sensor (VSS) input signals before replacing PCM.

Fuel Injector

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 PCM.
3. Disconnect fuel injector harness connector. Measure resistance between fuel injector terminals. If resistance is 10-14 ohms, go to next step. If resistance is not 10-14 ohms, replace fuel injector.
4. Check for injector leaks by removing injector fuel rail. Keep fuel hose and all injectors connected to rail. Turn ignition switch to RUN position. DO NOT start engine. Observe injector tips for leakage. If injectors drip, replace faulty injectors.

IDLE CONTROL SYSTEM

Note. Fast idle is actuated by fast idle cam. For fast idle cam adjustment procedure, see IDLE SPEED & MIXTURE in ADJUSTMENTS article.

Idle speed is controlled by PCM through IAC valve. PCM 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 the following input signals to PCM.

1. A/C Operation
2. Closed Throttle Position Switch
3. Crankshaft Position Sensor
4. Engine Coolant Temperature
5. Ignition (Start) Signal
6. Mass Airflow Sensor
7. Park/Neutral Switch
8. Power Steering Pressure Switch
9. Throttle Position Sensor
10. Vehicle Speed Sensor

IDLE AIR CONTROL (IAC) VALVE

See DTC P0505: IDLE AIR CONTROL (IAC) in appropriate TESTS W/CODES articles below.

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

FAST IDLE CONTROL DEVICE (FICD) SOLENOID

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

Ignition Coil

See IGNITION CHECKS in BASIC TESTING article.

Power Transistor

Faults in power transistor should set a DTC P1320. For testing procedure, refer to DTC P1320: IGNITION SIGNAL in appropriate TESTS W/CODES articles below.

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

Crankshaft Position Sensor

PCM depends upon crankshaft position sensor for RPM signals. PCM uses signals to determine triggering of power transistors and fuel injectors. See DTC P0335 OR P1336: CRANKSHAFT POSITION (CKP) SENSOR in appropriate TESTS W/CODES articles below.

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

See DTC P0340: CAMSHAFT POSITION (CMP) SENSOR in appropriate TESTS W/CODES articles below.

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

Timing Advance System

PCM controls ignition timing advance based upon sensor input signals that reflect ignition timing needs. If timing problems are experienced, inspect input signals listed below for proper operation. To check input signals, see ENGINE SENSORS & SWITCHES or PCM pin voltage charts in PIN VOLTAGE CHARTS article.

1. A/C Clutch Signal
2. Closed Throttle Position Switch
3. Crankshaft Position Sensor
4. Engine Coolant Temperature
5. Ignition (START) Signal
6. Mass Airflow Sensor
7. Park/Neutral Switch
8. Power Steering Pressure Switch
9. Throttle Position Sensor
10. Vehicle Speed Sensor

EXHAUST GAS RECIRCULATION (EGR)

PCM cuts and controls vacuum applied to EGR valve depending upon engine operating conditions. On Q45 (except Ca.) and I30, this is achieved by PCM control of the EGRC solenoid valve. (Scheme 69) On Q45 (Ca.), this is achieved by PCM control of EGR valve and EVAP canister purge control solenoid valve. (Scheme 70) On all models, when the following conditions are detected, PCM will discharge vacuum signal to EGR valve into the atmosphere based upon input signals received from various input components. See EGR SYSTEM INPUT SIGNALS table.

1. Low engine coolant temperature.
2. When engine is started or engine is idling.
3. Excessively high engine coolant temperature.
4. Mass Air Flow (MAF) sensor malfunction.
5. When Traction Control System (TCS) is operating (if equipped).

EGR SYSTEM INPUT SIGNALS

Scheme 69

Scheme 70

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 PCM terminal No. 103 (Blue/Black wire) on I30, terminal No. 10 (Blue/Yellow wire) on Q45.
3. With engine idling, DVOM should read zero volts. At 2000 RPM, DVOM should read battery voltage. See «EGR SYSTEM INPUT SIGNALS»(ref-18057-S01482813032000122900000) table. Also check EGRC solenoid power supply and harness between PCM and EGRC solenoid for open or short circuit.

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 vacuum port. (Scheme 71) 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 EGR backpressure transducer.

Scheme 71

See DTC P1401: EGR TEMPERATURE SENSOR in appropriate TESTS W/CODES articles below.

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

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 next step. Vacuum should hold on gauge. If vacuum does not hold, replace EGR valve.
2. Remove vacuum gauge. 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.

EGRC Solenoid

See DTC P0400: EGR FUNCTION or DTC 1400: EGR CONTROL (EGRC) SOLENOID in appropriate TESTS W/CODES articles below.

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

EGR Function

See DTC P0400 OR P1402: EGR FUNCTION in appropriate TESTS W/CODES articles below.

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

FUEL EVAPORATION (EVAP) CONTROL SYSTEM

Note. Faults in FUEL EVAPORATION system should set a Diagnostic Trouble Code (DTC). Refer to the appropriate testing procedures in appropriate TESTS W/CODES articles below for complete system and component testing. (Scheme 72)

1. For I30 see «TESTS W/CODES»(ref-18055)
2. For Q45 see «TESTS W/CODES»(ref-18056)

Scheme 72

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.

1. A/C clutch relay is controlled by PCM. Under normal conditions, PCM will engage clutch relay by providing a ground circuit for relay windings. If PCM 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, PCM will disengage relay.
2. A/C clutch relay (Blue or Green) is located in relay box on right side of engine compartment. On I30 and Q45, relay is in rearmost position.
3. Remove relay from relay box. Apply ground to terminal No. 2 of relay. (Scheme 73) 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. Replace relay if test values are not as specified.

Scheme 73