Engine Electrical Devices: Diagnosis Suzuki Aerio I

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

Note. Use voltmeter with high-impedance (10 kohm/V minimum) or digital type voltmeter.

Scheme 3

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1. Remove ECM, referring to «ENGINE CONTROL MODULE (ECM) REMOVAL AND INSTALLATION»(ref-251060-S32102796392007032000000) .
2. Connect couplers to ECM.
3. Disconnect coupler (1) from MAF and IAT sensor.
4. Connect voltmeter to "BLK/RED" wire terminal (3) of MAF and IAT sensor coupler (1) disconnected and ground (2).
5. Turn ignition switch ON and check that voltage is battery voltage. If not, check if wire harness is open or connection is poor.
6. Turn ignition switch OFF and connect MAF and IAT sensor coupler to MAF and IAT sensor.
7. Turn ignition switch ON and check voltage at "C46-29" terminal. "Standard" voltage between "C46-29" terminal and ground 0.5 - 1.0 V
8. Start engine and check that voltage is lower than 5 V and it rises as engine speed increases. Reference voltage 1.3 - 1.8 V at specified idle speed
9. If check result is not as specified, cause may lie in wire harness, coupler 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 in figure, replace MAF and IAT sensor.

Intake air temperature (IAT) sensor resistance

1.80 - 2.20 kohm at 25°C, 77°F

0.50 - 0.68 kohm at 60°C, 140°F

Scheme 5

Scheme 6

1. Disconnect connector from MAP sensor.
2. Remove MAP sensor.
3. Arrange 3 new 1.5 V batteries (2) in series (check that total voltage is 4.5 - 5.0 V) and connect its positive terminal to "Vin" terminal of sensor and negative terminal to "Ground" terminal. Then check voltage between "Vout" and "Ground". Also, check if voltage reduces when vacuum is applied up to 400 mmHg by using vacuum pump (3). If check result is not satisfactory, replace MAP sensor (1). Output voltage (When input voltage is 4.5 - 5.5 V, ambient temp. 20 - 30°C, 68 - 86°F) BAROMETRIC PRESSURE AND OUTPUT VOLTAGE SPECIFICATION Altitude (Reference) Barometric pressure Output voltage (ft) (m) (mmHg) (kPa) (V) 0 - 2000 0 - 610 760 - 707 100 - 94 3.3 - 4.3 2001 - 5000 611 - 1524 Under 707 over 634 94 - 85 3.0 - 4.1 5001 - 8000 1525 - 2438 Under 634 over 567 85 - 76 2.7 - 3.7 8001 - 10000 2439 - 3048 Under 567 over 526 76 - 70 2.5 - 3.3
4. Install MAP sensor (1) securely.
5. Connect MAP sensor (1) connector securely.

Scheme 7

1. Connect SUZUKI scan tool to DLC (1) with ignition switch OFF.
2. Check "TP Sensor Volt" value displayed on scan tool under the following each condition. If measured value is out of specified range, check TP sensor referring to Step 12 of «DTC P0121: THROTTLE POSITION SENSOR CIRCUIT RANGE / PERFORMANCE»(ref-251058-S37982889292007032000000) . If OK, check wire harness of TP sensor. Also check that "TP Sensor Volt" value varies according to throttle valve opening linearly. If not, it is possible that TP sensor has failed. Replace. Special Tool SUZUKI scan tool TP sensor voltage When throttle is fully close: 0.70 +/- 0.15 V When throttle is fully open: 4.0 +/- 0.5 V

Scheme 8

1. Remove ECM referring to «ENGINE CONTROL MODULE (ECM) REMOVAL AND INSTALLATION»(ref-251060-S32102796392007032000000) .
2. Connect couplers to ECM.
3. Using voltmeter, check voltage at "C46-22" terminal under the following each condition. If measured value is out of specified range, check TP sensor referring to Step 12 of «DTC P0121: THROTTLE POSITION SENSOR CIRCUIT RANGE / PERFORMANCE»(ref-251058-S37982889292007032000000) . If OK, check wire harness of TP sensor. Also check that voltage varies according to throttle valve opening linearly. If not, it is possible that TP sensor has failed. Replace. TP sensor voltage When throttle is fully close: 0.70 +/- 0.15 V When throttle is fully open: 4.0 +/- 0.5 V
4. Upon completion of checking, install ECM.

Engine Coolant Temperature (ECT) Sensor Inspection

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

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

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

Scheme 9

Heated Oxygen Sensor (Sensor-1 and Sensor-2) Inspection

Reference: HEATED OXYGEN SENSOR (SENSOR-1 AND SENSOR-2) REMOVAL AND INSTALLATION

Scheme 10

1. Disconnect sensor connector (1).
2. Using ohmmeter, measure resistance between terminals "V B " and "GND" of sensor connector. If found faulty, replace oxygen sensor. Resistance of oxygen sensor heater Sensor-1: 2 - 6 ohm at 20 °C, 68 °F Sensor-2: 4 - 10 ohm at 20 °C, 68 °F
3. Connect sensor connector securely.

Knock Sensor Inspection

Check knock sensor referring to DTC P0327 / P0328: KNOCK SENSOR CIRCUIT LOW / HIGH .

If malfunction is found, replace.

CMP (Camshaft Position) Sensor and Its Circuit Inspection

1. Confirm that terminal voltages and ground circuit continuity at CMP sensor connector terminals is in good condition referring to Step 4, 6, 8 and 12 of «DTC P0340: CAMSHAFT POSITION SENSOR CIRCUIT»(ref-251058-S20463759092007032000000) . If terminal voltages and ground circuit continuity are specified value, go to next step. If terminal voltages or ground circuit continuity is out of specification, check and/or repair CMP sensor circuit. If CMP sensor circuits are in good condition, check ECM referring to «INSPECTION OF ECM AND ITS CIRCUITS»(ref-251058-S25437023172007032000000) .
2. Check that CMP sensor waveform as specified referring to "Reference Waveform No. 19 and No. 20" under «INSPECTION OF ECM AND ITS CIRCUITS»(ref-251058-S25437023172007032000000) . If waveform is out of specification, replace CMP sensor. If waveform as specified, CMP sensor is in good condition.

Crankshaft Position (CKP) Sensor Inspection

Check crankshaft position sensor resistance referring to Step 2 of DTC P0335: CRANKSHAFT POSITION SENSOR CIRCUIT . If resistance is out of specification, replace.

Vehicle Speed Sensor (VSS) and Its Circuit Inspection

1. Confirm that terminal voltages and ground circuit continuity at VSS connector terminals is in good condition referring to Step 5 to 7 of «DTC P0500: VEHICLE SPEED SENSOR»(ref-251058-S00073692422007032000000) . If terminal voltages and ground circuit continuity are specified value, go to next step. If terminal voltages or ground circuit continuity is out of specification, check and/or repair VSS circuit. If VSS circuits are in good condition, check ECM referring to «INSPECTION OF ECM AND ITS CIRCUITS»(ref-251058-S25437023172007032000000) .
2. Check that VSS signal voltage varies from low to high or from high to low as specified referring to Step 14 of «DTC P0500: VEHICLE SPEED SENSOR»(ref-251058-S00073692422007032000000) . If signal voltage varies as specified, VSS is in good condition. If signal voltage varies out of specification, replace VSS.

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1. Disconnect negative cable at battery.
2. Remove main relay (1) from relay box (2).
3. Check resistance between each two terminals as follows. If check results are as specified, proceed to next operation check. If not, replace. Main relay resistance Between terminals "A" and "B": (Infinity) Between terminals "C" and "C": 160 - 240 ohm
4. Check that there is continuity between terminals "A" and "B" when battery is connected to terminals "C" and "D". If found defective, replace.