Engine Electrical Devices: Diagnosis Suzuki SX4 I

Electric Throttle Body Assembly On-Vehicle Inspection

Accelerator Pedal Position (APP) Sensor Assembly Inspection

Check APP sensor (main and sub) output voltage as the following steps.

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Scheme 3

1. For APP sensor (main), arrange 3 new 1.5 V batteries (1) in series (check that total voltage is 4.5 - 5.0 V) and connect its positive terminal to "Vin 1" terminal (2) and negative terminal to "Ground 1" terminal (3) of sensor. Then using voltmeter, connect positive terminal to "Vout 1" terminal (4) of sensor and negative terminal to battery.
2. For APP sensor (sub), arrange 3 new 1.5 V batteries (1) in series (check that total voltage is 4.5 - 5.0 V) and connect its positive terminal to "Vin 2" terminal (2) and negative terminal to "Ground 2" terminal (3) of sensor. Then using voltmeter, connect positive terminal to "Vout 2" terminal (4) of sensor and negative terminal to battery.
3. Measure output voltage variation while accelerator pedal is released and fully depressed as the following specification. If sensor voltage is out of specified value or does not vary linearly as the following graph, replace APP sensor assembly.

APP sensor output voltage min. variation while accelerator pedal is released to depressed fully

APP sensor (main) [A]: 0.82 - 3.50 V

APP sensor (sub) [B]: 0.44 - 1.74 V

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1. Disconnect negative cable at battery.
2. Drain coolant referring to «COOLING SYSTEM»(ref-268900-S23854444352007102700000) . WARNING: To avoid danger of being burned, do not remove radiator cap while engine and radiator are still hot. Scalding fluid and steam can be blown out under pressure if cap is taken off too soon.
3. Disconnect connector from ECT sensor (1).
4. Remove ECT sensor from water outlet cap.

Engine Coolant Temperature (ECT) Sensor Inspection

Reference: ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL AND INSTALLATION

Immerse temperature sensing part of ECT sensor in water (or ice) and measure resistance between sensor terminals while heating water gradually.

If measured resistance doesn't show such characteristic as shown, replace ECT sensor.

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Scheme 7

1. Disconnect A/F sensor connector.
2. Using ohmmeter, measure resistance of Sensor heater between terminals "VB" and "GND" at sensor connector. If found faulty, replace A/F sensor. NOTE: Temperature of sensor affects resistance value largely. Make sure that sensor heater is at correct temperature. A/F sensor heater resistance 2 - 3 ohms at 20 °C (68 °F)
3. Connect A/F sensor connector securely.

Scheme 8

1. Disconnect sensor connector.
2. Using ohmmeter, measure resistance of sensor heater between terminals "V B " and "GND" at sensor connector. If found faulty, replace oxygen sensor. NOTE: Temperature of sensor affects resistance value largely. Make sure that sensor heater is at correct temperature. HO2S heater resistance 5.0 - 6.4 ohms at 20 °C (68 °F)
3. Connect sensor connector securely.

Camshaft Position (CMP) Sensor Inspection

Reference: CAMSHAFT POSITION (CMP) SENSOR REMOVAL AND INSTALLATION

Scheme 9

1. Check that O-ring is free from damage.
2. Check that end face of sensor and signal rotor tooth are free from any metal particles and damage.

Crankshaft Position (CKP) Sensor Inspection

Reference: CRANKSHAFT POSITION (CKP) SENSOR REMOVAL AND INSTALLATION

Mass Air Flow (MAF) and Intake Air Temperature (IAT) Sensor On-Vehicle Inspection

Note. Before performed this inspection, be sure to read the PRECAUTIONS OF ECM CIRCUIT INSPECTION .

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1. Disconnect MAF and IAT sensor connector.
2. Connect voltmeter to "BLU/RED" wire terminal (2) of MAF and IAT sensor connector (1) disconnected and ground.
3. Turn ON ignition switch and check that voltage is battery voltage. If not, check if wire harness is open or connection is poor.
4. Turn OFF ignition switch and connect connector to MAF and IAT sensor.
5. Connect special tool between ECM and ECM connector referring to «INSPECTION OF ECM AND ITS CIRCUITS»(ref-268916-S20667330622007102700000)
6. Turn ON ignition switch and check MAF signal voltage between "C01-26" terminal circuit and "C01-27" terminal circuit of special tool. MAF signal voltage between "C01-26" terminal circuit and "C01-27" terminal circuit of special tool MAF signal voltage of MAF and IAT sensor with ignition switch turned ON: 0.5 - 1.0 V
7. Start engine and check that voltage is lower than 5 V and it rises as engine speed increases. MAF signal voltage between "C01-26" terminal circuit and "C01-27" terminal circuit of special tool MAF signal reference voltage of MAF and IAT sensor at specified Idle speed: 1.0 - 1.5 V
8. If check result is not as specified above, cause may lie in wire harness, connector connection, MAF and IAT sensor or ECM.

Mass Air Flow (MAF) and Intake Air Temperature (IAT) Sensor Inspection

Reference: MASS AIR FLOW (MAF) AND INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL AND INSTALLATION

1. Check sensor O-ring (1) for damage and deterioration. Replace as necessary.
2. Blow hot air to temperature sensing part (2) of MAF and IAT sensor (3) using hot air drier (4) and measure resistance between sensor terminals while heating air gradually. If measured resistance does not show such characteristic as shown, replace MAF and IAT sensor. Intake air temperature sensor resistance -20 °C (-4 °F): 13.6 - 18.4 kohms 20 °C (68 °F) : 2.21 - 2.69 kohms 60 °C (140 °F): 0.493 - 0.667 kohms

IMT Valve Actuator Inspection

Reference: "IMT Valve Actuator Removal and Installation"

Scheme 12

1. Connect battery positive (+) and negative (-) terminals to IMT valve actuator (1) as shown in table below. If it does not operate as specified direction, replace IMT valve actuator. ROTATIVE DIRECTION - IMT VALVE ACTUATOR Rotative direction a b clockwise + - counterclockwise - +