Engine Control System: Diagnosis Mazda 3 BK

NEUTRAL SWITCH INSPECTION

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

Scheme 538

Scheme 539

1. Remove the neutral switch. (See «NEUTRAL SWITCH REMOVAL/INSTALLATION»(ref-177777-S28692497502005060700000) .)
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»(ref-177569-S36968866842005060200000) . If it cannot be verified, replace the neutral switch.

Scheme 540

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

1. Open circuit 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 GND

1. Short circuit If there is continuity in the following wiring harnesses, there is a short circuit. Repair or replace the wiring harness. Neutral switch terminal B and GND

CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION

Note. Before performing the following inspection, make sure to follow the troubleshooting flowchart. (See FOREWORD .)

Scheme 541

Scheme 542

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»(ref-177569-S29588773302005060200000) . If there is any malfunction, replace the CPP switch.

Circuit Open/Short Inspection

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)

1. Open circuit If there is no continuity in the following wiring harnesses, there is an open circuit. Repair or replace the wiring harness. CPP switch terminal B and PCM terminal 1O CPP switch terminal A and body GND

1. Short circuit If there is continuity in the following wiring harnesses, there is a short circuit. Repair or replace the wiring harness. CPP switch terminal B and body GND CPP switch terminal B and power supply

Scheme 543

1. Remove the battery cover.
2. Disconnect the negative battery cable.
3. Remove the plug hole cover.
4. Drain the engine coolant. (See ENGINE COOLANT REPLACEMENT .)
5. Disconnect the ECT sensor connector.
6. Remove the ECT sensor using the SST.
7. Install in the reverse order of removal. Tightening torque 10-14 N.m {102-142 kgf.cm, 89-123 in.lbf}

Resistance Inspection

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

1. Disconnect the ECT sensor connector.
2. Remove the ECT sensor. (See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION»(ref-177569-S19762163712005060200000) .)
3. Place the ECT sensor in the water and while increasing the water temperature, measure the resistance between ECT sensor terminals A and B. If the monitor item status/specification (reference) is not within the specification, even though the ECT sensor resistance is within the specification, perform the «Circuit Open/Short Inspection»(ref-177569-S12635782572005060200000) . If not within the specification, replace the ECT sensor.

Scheme 544

Scheme 545

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

INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION

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

1. Disconnect the mass air flow sensor connector.
2. Verify that the resistance between MAF sensor terminals D and E is within the specification. If the monitor item status/specification (reference) is not within the specification, even though the IAT sensor resistance is within the specification, perform the «Circuit Open/Short Inspection»(ref-177569-S35965745462005060200000) . If not within the specification, replace the MAF sensor.

Scheme 546

Scheme 547

Scheme 548

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

1. Open circuit If there is no continuity, there is an open circuit. Repair or replace the wiring harness. MAF/IAT sensor terminal D and PCM terminal 1AH MAF/IAT sensor terminal E and PCM terminal 1AA

1. Short circuit If there is continuity, there is a short circuit. Repair or replace the wiring harness. MAF/IAT sensor terminal E and power supply MAF/IAT sensor terminal D and power supply MAF/IAT sensor terminal D and body GND

CRANKSHAFT POSITION (CKP) SENSOR INSPECTION

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

1. Disconnect the CKP sensor connector.
2. Measure the resistance between CKP sensor connector terminals A and B. If not within the specification, replace the CKP sensor. If the monitor item status/specification (reference) is not within the specification, even though the resistance is within the specification, perform the «Circuit Open/Short Inspection»(ref-177569-S30412737112005060200000) , and repair or replace the malfunctioning part.

1. Resistance 400-550 ohms

Scheme 549

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

CAMSHAFT POSITION (CMP) SENSOR INSPECTION

Note. Before performing the following inspection, make sure to follow the troubleshooting flowchart. (See FOREWORD .)

1. Disconnect the CMP sensor connector.
2. Measure the resistance between CMP sensor connector terminals A and B. If not within the specification, replace the CMP sensor. If the monitor item status/specification (reference) is not within the specification, even though the resistance is within the specification, perform the «Circuit Open/Short Inspection»(ref-177569-S28022134042005060200000) , and repair or replace the malfunctioning part. Resistance 400-550 ohms

Scheme 550

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

VARIABLE TUMBLE SHUTTER VALVE SWITCH INSPECTION

Note. Perform the following inspection only when directed.

Scheme 551

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 tumble shutter valve actuator rod is depressed and released by hand. If not as specified, perform the «Circuit Open/Short Inspection»(ref-177569-S12966881352005060200000) . If there is no open or short circuit, replace the intake manifold.

Scheme 552

Scheme 553

Scheme 554

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

THROTTLE POSITION (TP) SENSOR INSPECTION

Note. Before performing the following inspection, make sure to follow the troubleshooting flowchart. (See FOREWORD .)

Scheme 555

Scheme 556

1. Verify that no DTC related to APP sensor has been detected. If any DTCs related to APP sensor have been detected, perform the DTC inspection. (See DTC TABLE .)
2. Connect the WDS or equivalent to the DLC-2.
3. Turn the ignition switch to ON position.
4. Select TP1 or TP2 PID (percentage) on the WDS or equivalent.
5. Verify that the TP1 or TP2 PID is within the specification when the accelerator pedal not depressed. (See «PCM INSPECTION»(ref-177569-S27099057202005060200000) .)
6. Operate the accelerator pedal and verify that the TP1 or TP2 PID (percentage) changes as shown in the following graph. If not verified, perform the «Circuit Open/Short Inspection»(ref-177569-S33263902962005060200000) . If there is no open or short circuit, replace the throttle body. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [LF] , INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [L3] .)

Scheme 557

Scheme 558

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

ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION

Note. Before performing the following inspection, make sure to follow the troubleshooting flowchart. (See FOREWORD .)

Scheme 559

1. Connect the WDS or equivalent to the DLC-2.
2. Turn the ignition switch to ON position.
3. Select APP1 and APP2 PID on the WDS or equivalent.
4. Verify that the APP1 and APP2 PID is within the specification when the accelerator pedal not depressed. (See «PCM INSPECTION»(ref-177569-S27099057202005060200000) .)

Scheme 560

Scheme 561

Scheme 562

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

MASS AIR FLOW (MAF) SENSOR INSPECTION

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

Visual Inspection

1. Visually inspect the MAF sensor for the following: Damage, cracks Rusted sensor terminal Bent sensor terminal If there is any malfunction, replace the MAF 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»(ref-177569-S35664749032005060200000) .

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 1AC (WDS PID: MAF) varies. If it cannot be verified even though the related harnesses have no malfunction, replace the MAF/IAT sensor. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [LF] , INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [L3] .)

Scheme 563

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION»(ref-177569-S38589701122005060200000) .)
2. Disconnect the MAF sensor connector.
3. Inspect the following wiring harnesses for an open or short circuit. (Continuity inspection)

Front HO2S circuit open/short inspection (sensor)

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

Scheme 564

1. If there is no continuity in the following wiring harnesses, there is an open circuit. Repair or replace the wiring harness. Front HO2S terminal A and PCM terminal 2AG Front HO2S terminal B and PCM terminal 2AC Front HO2S terminal C and PCM terminal 2G Front HO2S terminal D and main relay terminal E

Scheme 565

Scheme 566

1. If there is continuity in the following wiring harnesses, there is a short circuit. Repair or replace the wiring harness. Front HO2S terminal A and body ground Front HO2S terminal A and power supply Front HO2S terminal B and body ground Front HO2S terminal B and power supply Front HO2S terminal D and body ground

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

Front HO2S heater circuit open/short inspection (heater)

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

MIDDLE HEATED OXYGEN SENSOR (HO2S) INSPECTION [CALIFORNIA EMISSION REGULATION APPLICABLE MODEL]

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

Scheme 567

1. Warm up the engine to normal operating temperature.
2. Using the WDS or equivalent, monitor the following: Vehicle speed (PID: VSS) Engine speed (PID: RPM) Middle HO2S Current (PID: O2S12)
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 middle HO2S outputs a voltage of 0.6 V or more, one time or more, then verify that the middle HO2S current (PID: O2S12) is 0.3 V or less while decelerating as shown in the figure. If not within the specification, inspect the HO2S for an open or short circuit. (See «Middle HO2S Circuit Open/Short Inspection (Sensor)»(ref-177569-S11329173342005060200000) .) Then if there is no malfunction in the wiring harness, replace the middle HO2S.

Middle HO2S Circuit Open/Short Inspection (Sensor)

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

Middle HO2S Circuit Open/Short Inspection (Heater)

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

Scheme 568

1. If there is no continuity, there is an open circuit. Repair or replace the wiring harness. HO2S terminal C and main relay terminal E HO2S terminal D and PCM terminal 2C

Scheme 569

1. If there is no continuity, there is a short circuit. Repair or replace the wiring harness. Front and middle HO2S terminal C and body GND HO2S terminal D and power supply HO2S terminal D and body GND

Rear HO2S circuit open/short inspection (sensor)

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

Rear HO2S circuit open/short inspection (heater)

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

Scheme 570

1. If there is no continuity, there is an open circuit. Repair or replace the wiring harness. HO2S terminal C and main relay terminal E HO2S terminal D and PCM terminal 2D

Scheme 571

1. If there is no continuity, there is a short circuit. Repair or replace the wiring harness. Front and rear HO2S terminal C and body GND HO2S terminal D and power supply HO2S terminal D and body GND

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

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

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR INSPECTION

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

1. Remove the MAP sensor with the connector still connected. (See «MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR REMOVAL/INSTALLATION»(ref-177569-S36301508872005060200000) .)
2. Remove the vacuum hose of the MAP sensor.
3. Verify that the voltage at PCM terminal 2AL is within the specification when the ignition switch is turned to the ON position. If not within the specification, replace the MAP sensor. Voltage 2.69-4.37 V
4. Install the vacuum pump.
5. Turn the ignition switch to the ON position.
6. Verify that change in voltage is within the specification when a vacuum of 30 kPa {225 mmHg, 8.86 inHg} is applied using a vacuum pump. If not within the specification, replace the MAP sensor. Voltage variance 1.16-1.27 V

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

Scheme 572

1. If there is no continuity, there is an open circuit. Repair or replace the wiring harness. MAP sensor terminal A and PCM terminal 2AA MAP sensor terminal D and PCM terminal 2AL MAP sensor terminal C and PCM terminal 2W

KNOCK SENSOR (KS) INSPECTION

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

1. Disconnect the knock sensor connector.
2. Measure resistance between KS terminals A and B. If not within the specification, replace the KS. If the monitor item status/specification (reference) is not within the specification, even though the KS resistance is within the specification, perform the "Circuit Open/Short Inspection". Resistance Approx. 4.87 megohms

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

Scheme 573

1. If there is no continuity, there is an open circuit. Repair or replace the wiring harness. Knock sensor terminal A and PCM terminal 2Q Knock sensor terminal B and PCM terminal 2R

BAROMETRIC PRESSURE (BARO) SENSOR INSPECTION

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

1. Remove the BARO sensor with the connector still connected.
2. Turn the ignition switch to the ON position.
3. Verify that the voltage at PCM terminal 1AG (WDS PID: BARO) is within the specification. If not within the specification even though the related wiring harnesses have no malfunction, replace the BARO sensor. BARO sensor output voltage 2.3-4.7 V
4. Disconnect the BARO sensor hose.
5. Install a vacuum pump to the BARO sensor.
6. Apply a vacuum of 30 kPa {225 mmHg, 8.86 inHg} to the BARO sensor and verify that change in voltage at PCM terminal 1AG (WDS PID: BARO) is within the specification. If not within the specification, replace the BARO sensor. BARO sensor output voltage variance 0.97-1.41 V

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

Scheme 574

1. If there is no continuity, there is an open circuit. Repair or replace the wiring harness. Barometric pressure sensor terminal A and PCM terminal 1AG Barometric pressure sensor terminal B and PCM terminal 1AA Barometric pressure sensor terminal C and PCM terminal 1AE