Engine Controls - System/component Tests 3.0: Other Infiniti I30 I

Ground Circuits

1. Using an ohmmeter, check for continuity to ground on ECM terminals No. 10, 19, 25, 32, 43, 108, 116 and 124. (Scheme 63) 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. Turn ignition switch to ON position. Using a voltmeter, check for battery voltage between chassis ground and ECM terminals No. 24, 67 and 72. (Scheme 63) If battery voltage is not present, check fusible link and fuse "G".
2. Turn ignition switch to OFF position. Using a voltmeter, check for battery voltage between chassis ground and ECM power back-up terminal No. 80. If battery voltage is not present, check for overheated relays, fusible links and wiring.

Scheme 63

ENGINE SENSORS & SWITCHES

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

CRANKSHAFT POSITION (CKP) SENSOR

Faults in CKP sensor or circuit should set a Diagnostic Trouble Code (DTC) PO335 or P1336. For testing procedure, refer to DTC PO335 & P1336: CRANKSHAFT POSITION (CKP) SENSOR in appropriate TESTS W/CODES article.

CAMSHAFT POSITION (CMP) SENSOR

Faults in CMP sensor or circuit should set a Diagnostic Trouble Code (DTC) PO340. For testing procedure, refer to DTC PO340: CAMSHAFT POSITION (CMP) SENSOR in appropriate TESTS W/CODES article.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

Faults in ECT sensor or circuit should set a Diagnostic Trouble Code (DTC) PO115 or P0125. For testing procedure, refer to DTC P0115 OR P0125 - ENGINE COOLANT TEMPERATURE (ECT) SENSOR in appropriate TESTS W/CODES article.

EGR TEMPERATURE SENSOR

Faults in EGR temperature sensor or circuit, should set a Diagnostic Trouble Code (DTC) P1401. For testing procedure, refer to DTC P1401, EGR TEMPERATURE SENSOR in appropriate TESTS W/CODES article.

FUEL TEMPERATURE SENSOR

Faults in Fuel Temperature Sensor or circuit should set a Diagnostic Trouble Code (DTC) PO180. For testing procedure, refer to DTC P0180: FUEL TEMPERATURE SENSOR in appropriate TESTS W/CODES article.

INTAKE AIR TEMPERATURE (IAT) SENSOR

Faults in IAT sensor or circuit should set a Diagnostic Trouble Code (DTC) PO110. For testing procedure, refer to DTC P0110: INTAKE AIR TEMPERATURE (IAT) SENSOR in appropriate TESTS W/CODES article.

LEFT FRONT HEATED OXYGEN SENSOR

Faults in left front Heated Oxygen Sensor (HO2S) or circuit should set a Diagnostic Trouble Code (DTC) PO150 or P0155. For testing procedure, refer to DTC P0150 OR P0155: FRONT HEATED OXYGEN SENSOR (HO2S) in appropriate TESTS W/CODES article.

RIGHT FRONT HEATED OXYGEN SENSOR

Faults in right front Heated Oxygen Sensor (HO2S) or circuit should set a Diagnostic Trouble Code (DTC) PO130 or P0135. For testing procedure, refer to DTC P0130 OR P0135: FRONT HEATED OXYGEN SENSOR (HO2S) in appropriate TESTS W/CODES article.

RIGHT REAR OR REAR HEATED OXYGEN SENSOR

Faults in right rear or rear Heated Oxygen Sensor (HO2S) or circuit should set a Diagnostic Trouble Code (DTC) PO136 or P0141. For testing procedure, refer to DTC P0136 OR P0141: RIGHT REAR HEATED OXYGEN SENSOR (HO2S) in appropriate TESTS W/CODES article.

KNOCK SENSOR (KS)

Faults in knock sensor or circuit, should set a Diagnostic Trouble Code (DTC) PO325. For testing procedure, refer to DTC P0325: KNOCK SENSOR (KS) in appropriate TESTS W/CODES article.

MASS AIRFLOW (MAF) SENSOR

Faults in MAF sensor circuit should set a Diagnostic Trouble Code (DTC) PO100. For testing procedure, refer to DTC P0100: MASS AIRFLOW (MAF) SENSOR in appropriate TESTS W/CODES article.

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

1. Backprobe ECM terminal No. 20 with positive lead of DVOM. (Scheme 68)or (Scheme 69). Connect negative lead to chassis ground.
2. 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.

THROTTLE POSITION (TP) SENSOR

Faults in TP sensor circuit should set DTC P0120. To test system, see DTC P0120: THROTTLE POSITION (TP) SENSOR diagnostic procedures in appropriate TESTS W/CODES article. Vehicle Speed Sensor

Faults in vehicle speed sensor circuit should DTC P0500. To test system, see DTC P0500: VEHICLE SPEED SENSOR (VSS) diagnostic procedures in appropriate TESTS W/CODES article.

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 table. On all relays, apply battery voltage and ground to terminals No. 1 and 2. (Scheme 64), (Scheme 65) or (Scheme 66).
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.

RELAY LOCATION & IDENTIFICATION

Scheme 64

Scheme 65

Scheme 66

Canister Purge Solenoid

Faults in canister purge solenoid valve or circuit should set a Diagnostic Trouble Code (DTC) PO443. For testing procedure, refer to DTC PO443: CANISTER PURGE CONTROL VAVLE in appropriate TESTS W/CODES article.

EGRC Solenoid

Faults in EGRC solenoid or circuit should set a Diagnostic Trouble Code (DTC) PO400 or P1400. For testing procedure, refer to DTC P0400: EGR FUNCTION or DTC 1400: EGR CONTROL (EGRC) SOLENOID in appropriate TESTS W/CODES article.

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-18032) article. If results are not as specified, replace fuel pressure regulator.

Fuel Pump

1. 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. If no faults are found, check fuel pump control module. See DTC P1220: FUEL PUMP CONTROL MODULE (FPCM) in appropriate «TESTS W/CODES»(ref-18020) article.
2. If fuel pump control is okay, disconnect fuel pump/sending unit connector at fuel tank. Check resistance across fuel pump terminals. At 68°F (20°C), ohmmeter should indicate less than 5 ohms. If resistance is not correct, replace fuel pump.

Scheme 67

Fuel Pump Control System

1. Unplug fuel pump relay. (Scheme 68) Turn ignition on. Check for battery voltage between ground and fuel pump relay 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, 10-amp fuse No. 17 and 15-amp fuse No. 32 in fuse panel.
2. Turn ignition off. Disconnect fuel pump. Disconnect dropping resistor harness connector. (Scheme 69) 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 circuit.
3. Leave ignition off. Disconnect ECM harness connector. Check continuity between fuel pump relay terminal No. 2 (Black/Pink wire) and ECM 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-18021-S11994584902000122900000) under RELAYS & SOLENOIDS.

Scheme 68

Scheme 69

Fuel Pump Control Module (FPCM)

Faults in FPCM or circuit should set a Diagnostic Trouble Code (DTC) P1220. For testing procedure, refer to see DTC P1220: FUEL PUMP CONTROL MODULE (FPCM) in appropriate TESTS W/CODES article.

Fuel Pump Relay

See RELAYS under RELAYS & SOLENOIDS.

Start signal from ignition switch is used for ECM control of fuel pump. See PIN VOLTAGE CHARTS article.

FUEL CONTROL

ECM controls fuel system based upon sensor input signals. If feedback system does not function properly, check input signals before replacing ECM.

FUEL CONTROL SYSTEM INPUT SIGNALS

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 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.

IDLE CONTROL SYSTEM

Idle speed is controlled by ECM through IAC valve. 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.

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

IDLE AIR CONTROL (IAC) VALVE

Faults in IAC valve or circuit should set a Diagnostic Trouble Code (DTC) PO505. For testing procedure, refer to DTC P0505: IDLE AIR CONTROL (IAC) in appropriate TESTS W/CODES article.

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 article.

Crankshaft Position Sensor

ECM depends upon crankshaft position sensor for RPM signals. ECM uses signals to determine triggering of power transistors and fuel injectors. Faults in CKP sensor or circuit should set a Diagnostic Trouble Code (DTC) PO335 or P1336. For testing procedure, refer to DTC PO335 OR P1336 - CRANKSHAFT POSITION (CKP) SENSOR in appropriate TESTS W/CODES article.

Faults in CMP sensor or circuit should set a Diagnostic Trouble Code (DTC) PO340. For testing procedure, refer to DTC PO340 - CAMSHAFT POSITION (CMP) SENSOR in appropriate TESTS W/CODES article.

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. See TIMING ADVANCE SYSTEM INPUT SIGNALS table. To check input signals, see ENGINE SENSORS & SWITCHES or ECM pin voltage charts in PIN VOLTAGE CHARTS article.

TIMING ADVANCE SYSTEM INPUT SIGNALS

Detonation (Knock) Retard

Check knock sensor wire for open or short to ground. Check knock sensor shield ground wire for continuity to ground. Check routing of knock sensor wire. Wire should not be routed close to spark plug wires or high output accessories.

Faults in knock sensor (detonation retard) circuit may set Code 34 or DTC P0325. To test system, refer to DTC PO340: CAMSHAFT POSITION (CMP) SENSOR in appropriate TESTS W/CODES article.

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 Control (EGRC) 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. 103.
3. With engine idling, voltmeter should read zero volts. At 2000 RPM, voltmeter should read battery voltage. See EGR SYSTEM INPUT SIGNALS table. Also check EGRC solenoid power supply and harness between ECM 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.
2. Connect hand-held vacuum pump to remaining vacuum port. (Scheme 70) Apply vacuum. Vacuum should not hold. If vacuum holds, replace transducer.
3. 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 70

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. 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.

EGR & Canister Control Solenoid

1. Faults in EGR and canister control solenoid circuit should set DTC P1400. To test circuit, see DTC P1400 diagnostic procedures in appropriate «TESTS W/CODES»(ref-18020) article.

EGR Function

Faults in EGR function circuit should set DTC P0400. To test function, DTC P0400 diagnostic procedures in appropriate TESTS W/CODES article.

Faults in exhaust gas temperature sensor circuit should set DTC P1401. To test system, see DTC P1401: EGR TEMPERATURE SENSOR diagnostic procedures in appropriate TESTS W/CODES article.

FUEL EVAPORATION

Faults in FUEL EVAPORATION system should set a Diagnostic Trouble Code (DTC) PO440. For testing procedure, refer to P0440: EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM in appropriate TESTS W/CODES article.

Carbon Canister

Remove hoses from canister. Pinch off fresh air vent hose. (Scheme 71) Apply low volume air pressure through port "A" of canister. Air should pass freely out of port "B" of canister. Replace carbon canister if airflow is not as specified.

Scheme 71

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 rearmost position.
3. Remove relay from relay box. Apply ground to terminal No. 2 of relay. (Scheme 72) 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 72