Engine Control System (L3 with TC): Diagnosis Mazda 3 BL

PCM INSPECTION [L3 WITH TC]

NEUTRAL SWITCH INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart.

Scheme 83

1. Remove the neutral switch. (See «NEUTRAL SWITCH REMOVAL/INSTALLATION [A26M-R]».)
2. Verify that the continuity between neutral switch terminals A and B is as indicated in the table. If it can be verified, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". If it cannot be verified, replace the neutral switch. CONTINUITY REFERENCE Measured condition Continuity Rod pushed Continuity detected Except above No continuity

Scheme 84

1. Disconnect the PCM connector.
2. Inspect the following wiring harness for an open or short circuit. (Continuity inspection)

Scheme 85

1. If there is no continuity in the following wiring harnesses, there is an open circuit. Repair or replace the wiring harness. Neutral switch terminal A and PCM terminal 1S Neutral switch terminal B and body ground

CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the troubleshooting flowchart. (See «FOREWORD [LF, L3]».)

Scheme 86

1. Remove the CPP switch.
2. Verify that the continuity between CPP switch terminals A and B is as indicated in the table. If there is no malfunction, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". If there is any malfunction, replace the CPP switch. CONTINUITY REFERENCE Measurement condition Continuity Push the rod. No continuity Except above Continuity detected

Scheme 87

1. Disconnect the PCM connector.
2. Disconnect the CPP switch connector.
3. Inspect the following wiring harnesses for an open or short circuit. (Continuity inspection)

POWER STEERING PRESSURE (PSP) SWITCH INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

Continuity Inspection

1. Inspect the following if the power steering is inoperative (See «POWER STEERING FLUID INSPECTION».): Power steering fluid level Power steering fluid leakage Power steering fluid pressure
2. Disconnect the PSP switch connector.
3. Start the engine.
4. Inspect for continuity between the PSP switch terminal and ground using a tester. If not as specified, replace the PSP switch. (See «POWER STEERING OIL PUMP REMOVAL/INSTALLATION [L3 WITH TC]».) If the PSP switch is normal, but PID value is out of specification, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ".

Specification

Scheme 88

Scheme 89

Scheme 90

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]» ).
2. Inspect the following harnesses for an open or short circuit. (Continuity check)

VARIABLE SWIRL SHUTTER VALVE SWITCH INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

Scheme 91

Scheme 92

1. Turn the ignition switch to the ON position (Engine off).
2. Verify that the PCM terminal 2AE voltage is as shown in the following table when the variable swirl shutter valve actuator rod is depressed and released by hand. If not as specified, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". If there is no open or short circuit, replace the intake manifold. (See «INTAKE AIR SYSTEM REMOVAL/INSTALLATION [L3 WITH TC]».) VOLTAGE SPECIFICATION Condition PCM terminal 2AE Released (Open position) B+ Depressed (Closed position) Below 1.0 V

Scheme 93

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]» ).
2. Inspect the following harnesses for an open or short circuit. (Continuity check)

ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

ECT Sensor Resistance Inspection

1. Drain the engine coolant. (See «COOLING SYSTEM SERVICE WARNINGS [L3 WITH TC]».)
2. Remove the ECT sensor (located above the starter).
3. Place the ECT sensor in water with a thermometer, and heat the water gradually.
4. Measure the resistance between the ECT sensor terminals A and B using a tester. If not as specified, replace the ECT sensor. If the ECT sensor is normal, but PID value is out of specification, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". WATER TEMPERATURE AND RESISTANCE SPECIFICATION Water temperature (°C {°F}) Resistance (kilohm) 20 {68} 35.48-39.20 80 {176} 3.65-4.02

Scheme 94

Scheme 95

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]» ).
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

Visual Inspection

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

1. Visually inspect for the following on the MAF sensor. (See «INTAKE AIR SYSTEM REMOVAL/INSTALLATION [L3 WITH TC]».) Damage Cracks Bent terminals Terminal rust If any of the above are found, replace the MAF/IAT sensor. If the monitor item status/specification (reference) is not within the specification even though there is no malfunction, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ".

Voltage Inspection

1. Remove the MAF/IAT sensor without disconnect the MAF/IAT sensor connector.
2. Turn the ignition switch to the ON position.
3. As the air gradually approaches the MAF detection part of the MAF/IAT sensor, verify that the voltage at PCM terminal 1AK (M-MDS PID: MAF) varies. If it cannot be verified even though the related harnesses have no malfunction, replace the MAF/IAT sensor.

Scheme 96

Scheme 97

Scheme 98

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]» ).
2. Disconnect the MAF/IAT sensor connector.
3. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

Resistance Inspection

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

Scheme 99

1. Disconnect the MAF/IAT sensor.
2. Measure the resistance between the MAF/IAT sensor terminals D and E using a tester. If not as specified, replace the MAF/IAT sensor. (See «INTAKE AIR SYSTEM REMOVAL/INSTALLATION [L3 WITH TC]».) If the MAF/IAT sensor is normal, but the PID is out of specification, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". AMBIENT TEMPERATURE AND RESISTANCE SPECIFICATION Ambient temperature (°C {°F}) Resistance (kilohm) 20 {68} 2.21-2.69 60 {140} 0.493-0.667

Scheme 100

Scheme 101

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]» ).
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR INSPECTION [L3 WITH TC]

Note. Perform the following inspection only when directed. The following vacuum values are indicated by relative pressure from the MAP sensor.

1. Connect the M-MDS to the DLC-2.
2. Turn the ignition switch to ON (Engine off).
3. Select MAP PID on the M-MDS.
4. Verify that the MAP PID (pressure) and barometric pressure are practically equal. If not as verified, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". If there is no open or short circuit, replace the MAP sensor. If as verified, go to next step.
5. Apply vacuum of -25.0 kPa {-187 mmHg, -7.38 inHg} to the MAP sensor, and verify that the MAP variation from that of Step 4 is approx. 25.0 kPa {187 mmHg, 7.38 inHg}. If not as verified, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". If there is no open or short circuit, replace the barometric pressure sensor. (See «INTAKE AIR SYSTEM REMOVAL/INSTALLATION [L3 WITH TC]».)

Scheme 102

Scheme 103

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]» ).
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

Scheme 104

1. Disconnect MAP/boost air temperature sensor.
2. Measure the resistance between the MAP/boost air temperature sensor terminals A and B using a tester. If not as specified, replace the MAP/boost air temperature sensor. (See «INTAKE AIR SYSTEM REMOVAL/INSTALLATION [L3 WITH TC]».) If the MAP/boost air temperature sensor is normal, but PID are out of specification, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". AMBIENT TEMPERATURE AND RESISTANCE SPECIFICATION Ambient temperature (°C {°F}) Resistance (kilohm) 20 {68} 2.4-2.7 60(140} 0.59-0.64

Scheme 105

Scheme 106

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]» ).
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

THROTTLE POSITION (TP) SENSOR INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

Scheme 107

Scheme 108

1. Verify that no DTC related to the APP sensor has been detected. If any DTCs related to the APP sensor have been detected, perform the DTC inspection. (See «DTC TABLE [L3 WITH TC]»(/mazda/3/bl-2008-2011/remont/testing-diagnostics/#on-board-diagnostic-engine-controls-l3-with-tc) .)
2. Start the engine and warm it up (ECT: more than 80°C {176 °F}) .
3. Turn the ignition switch to the ON position (Engine off).
4. Verify that the PCM terminal 2AK and 2AL change smoothly while the throttle valve is gradually opened. If as verified, go to next step. If not as verified, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". If there is no open or short circuit, replace the throttle body.
5. Verify that the PCM terminal 2AK and 2AL voltages are as shown in the following table. If the voltage is not according to the following table, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". If there is no open or short circuit, replace the throttle body. VOLTAGE SPECIFICATION Condition PCM terminal 2AK (TP sensor No.1) PCM terminal 2AL (TP sensor No.2) APP is released 0.4-0.6 V 4.4-4.6 V APP is depressed 4.7-4.9 V 0.1-0.3 V

Scheme 109

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]» ).
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

Scheme 110

1. Turn the ignition switch to the ON position (Engine off).
2. Verify that the PCM terminal 1Y and 1 AC change smoothly while throttle valve is gradually opened. If as verified, go to next step. If not as verified, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". If there is no open or short circuit, replace the throttle body. (See «INTAKE AIR SYSTEM REMOVAL/INSTALLATION [L3 WITH TC]».)
3. Verify that the PCM terminal 1Y and 1 AC voltages are as shown in the following table. If the voltage is not according to the following table, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". If there is no open or short circuit, replace accelerator pedal. (See «ACCELERATOR PEDAL REMOVAL/INSTALLATION [L3 WITH TC]».) VOLTAGE SPECIFICATION Condition PCM terminal 1Y (APP sensor No.1) PCM terminal 1AC (APP sensor No.2) APP is depressed 3.65-3.93 V 3.10-3.38 APP is released 1.56-1.65V 1.01-1.10

Scheme 111

Scheme 112

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]».
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

FUEL PRESSURE SENSOR INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

1. Connect the M-MDS to the DLC-2.
2. Turn the ignition switch to the ON position (Engine off).
3. Select the FUEL_PRES PID on the M-MDS.
4. After warming up the engine, verify that the FUEL_PRES PID is at the standard value under the following conditions. If not as verified, replace the fuel delivery pipe. FUEL PRESSURE SPECIFICATION Step Condition FUEL_PRES PID 1 Idle 90 s after engine is started Approx. 3 MPa 2 Idle Spill valve solenoid valve connector is disconnected Approx. 530 kPa
5. After connecting the spill valve control solenoid valve connector, clear the DTC.

Scheme 113

Scheme 114

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]» ).
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

AIR FUEL RATIO (A/F) SENSOR, HEATED OXYGEN SENSOR (HO2S) INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

Scheme 115

1. Warm up the engine to normal operating temperature.
2. Using the M-MDS, monitor the following: Vehicle speed (PID: VSS) Engine speed (PID: RPM) A/F sensor current (PID: O2S11)
3. Drive the vehicle and decelerate the engine speed by releasing the accelerator pedal fully when the engine speed is 3,000 rpm or more.
4. Verify that the A/F sensor current (PID: O2S11) is 0.25 mA or more while decelerating as shown in the figure. If not within the specification, inspect the HO2S for an open or short circuit. (See «A/F SENSOR CIRCUIT OPEN/SHORT INSPECTION (SENSOR)» ). Then if there is no malfunction in the wiring harness, replace the A/F sensor.

Scheme 116

1. Disconnect the A/F sensor connector.
2. Measure the resistance between A/F sensor terminals 2B and 2D. If not within the specification, replace the A/F sensor. (See «AIR FUEL RATIO (A/F) SENSOR, HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [L3 WITH TC]» ). A/F sensor heater resistance 1-10 ohms

Scheme 117

Scheme 118

1. Disconnect the PCM connector.
2. Disconnect the A/F sensor connector.
3. Inspect the following wiring harnesses for an open or short circuit. (Continuity inspection)

HO2S Heater Circuit Open/Short Inspection (Heater)

1. Disconnect the PCM connector.
2. Disconnect the HO2S connector.
3. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. See «HOW TO USE THIS MANUAL».)

Scheme 119

1. Verify that the CKP sensor is securely installed.
2. Using a thickness gauge, measure the air gap between the plate projections at the back of crankshaft pulley and the CKP sensor. If not within the specification, inspect the plate projections for cracks or bending. If there is any malfunction, replace the plate. If the monitor item condition/specification (reference) is not within the specification, even though there is no malfunction, carry out the "Circuit Open/Short Inspection".

1. Disconnect the negative battery cable.
2. Remove the CKP sensor. (See «CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [L3 WITH TC]» ).
3. Verify that there are no metal shavings on the sensor. If the monitor item condition/specification (reference) is without the specification even though there is no malfunction, carry out the "Circuit Open/Short Inspection".

Scheme 120

1. Idle the engine. CAUTION: Water penetrating the connector will cause sensor malfunction. To prevent this, be careful not to damage the wiring harnesses or the waterproof connector so as to cause water penetration.
2. Measure the output voltage using an oscilloscope. If not within the specification, replace the CKP sensor. If the monitor item condition/specification (reference) is without the specification, even though the voltage is within the specification, carry out the "Circuit Open/Short Inspection". VOLTAGE SPECIFICATION Terminal Voltage (V) Condition A Below 1.0 Under any condition B 4.8 or more High output (1) 0.8 or less Low output (1) C B+ Under any condition (1) Output voltage varies with crankshaft rotation.

Scheme 121

1. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

CAMSHAFT POSITION (CMP) SENSOR INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

1. Remove the battery cover.
2. Disconnect the negative battery cable.
3. Remove the CMP sensor. (See «CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [L3 WITH TC]» ).
4. Verify that there are no metal shavings on the sensor. If the monitor item condition/specification (reference) is not within the specification even though there is no malfunction, carry out the "Circuit Open/Short Inspection".

Scheme 122

1. Idle the engine. CAUTION: Water penetrating the connector will cause sensor malfunction. To prevent this, be careful not to damage the wiring harnesses or the waterproof connector so as to cause water penetration.
2. Measure the output voltage using an oscilloscope. If not within the specification, replace the CMP sensor. If the monitor item condition/specification (reference) is not within the specification, even though the voltage is within the specification, carry out the "Circuit Open/Short Inspection". VOLTAGE SPECIFICATION Terminal Voltage (V) Condition A B+ Under any condition B Below 1.0 Under any condition C 4.8 or more High output (1) 0.8 or less Low output (1) (1) Output voltage varies with camshaft rotation.

Scheme 123

Scheme 124

Scheme 125

1. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

KNOCK SENSOR (KS) INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

1. Turn the ignition switch to the LOCK position.
2. Disconnect the KS connector.
3. Measure the resistance between KS terminals A and B using a tester. If not as specified, replace the KS. (See «KNOCK SENSOR (KS) REMOVAL/INSTALLATION [L3 WITH TC]» ). If the KS is normal, but the PID value is out of specification, perform the " «CIRCUIT OPEN/SHORT INSPECTION» ". Specification Approx. 4.87 megohms

Scheme 126

Scheme 127

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]» ).
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)

BAROMETRIC PRESSURE (BARO) SENSOR INSPECTION [L3 WITH TC]

Note. Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See «HOW TO USE THIS MANUAL».)

1. Connect the M-MDS to the DLC-2.
2. Turn the ignition switch to the ON position.
3. Select BARO on the M-MDS.
4. Verify that the BARO PID (pressure) and barometric pressure are practically equal. If not as verified, replace the PCM. (See «PCM REMOVAL/INSTALLATION [L3 WITH TC]» ).

See also:
• DTC TABLE [L3 WITH TC]