Engine Control System: Diagnosis Mazda RX-8 I

Inspection Using An Oscilloscope (Reference)

Note. The duty ratio for the wave pattern can vary with the control conditions. Therefore determine comprehensively where the malfunction occurs among the input systems, output systems, and the PCM.

Scheme 476

1. Terminal connected: 1B (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 0.4 ms/DIV (X), DC range
3. Measurement condition: IG SW ON

Scheme 477

1. Terminal connected1C (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 1 ms/DIV (X), DC range
3. Measurement condition: As soon as the accelerator pedal is fully released from the fully depressed position while the ignition switch is at ON (engine off).

Scheme 478

1. Terminal connected: 1V (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 50 ms/DIV (X), DC range
3. Measurement condition: Idling after warm-up (no load)

Scheme 479

1. Terminal connected: FS: 2G (+)-Negative battery terminal RS: 2D (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 5 ms/DIV (X), DC range
3. Measurement condition: Racing after warm-up (no load)

Scheme 480

1. Terminal connected: 21 (+)-Negative battery terminal
2. Oscilloscope setting: 0.5 V/DIV (Y): 1 ms/DIV (X), DC range
3. Measurement condition: Idling after warm-up (no load)

Scheme 481

Scheme 482

1. Terminal connected: FP1: 2M (+)-Negative battery terminal RP1: 2J (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 10 ms/DIV (X), DC range
3. Measurement condition: Idling after warm-up (no load)
4. Terminal connected: FP1: 2M (+)-Negative battery terminal RP1: 2J (+)-Negative battery terminal
5. Oscilloscope setting: 5 V/DIV (Y): 10 ms/DIV (X), DC range
6. Measurement condition: Cranking while the engine is cold. (ECT: Approx. 20 °C {68 °F})

Scheme 483

1. Terminal connected:2P (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 20 ms/DIV (X), DC range
3. Measurement condition: Idling after warm-up (no load) NOTE: Purge control might not be activated depending on the engine conditions.

Scheme 484

1. Terminal connected: 2T (+)-Negative battery terminal
2. Oscilloscope setting: 2 V/DIV (Y): 2 ms/DIV (X), DC range
3. Measurement condition: Idling after warm-up (no load)

Scheme 485

1. Terminal connected: 2U (+)-Negative battery terminal
2. Oscilloscope setting: 2 V/DIV (Y): 5 ms/DIV (X), DC range
3. Measurement condition: Idling after warm-up (no load)

Scheme 486

1. Terminal connected: 2W (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 2 ms/DIV (X), DC range
3. Measurement condition: Just after the ignition switch is off after warm-up (no load)

Scheme 487

1. Terminal connected: 2AB (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 2 ms/DIV (X), DC range
3. Measurement condition: Just after the ignition switch is off after warm-up (no load)

Scheme 488

1. Terminal connected: 2V (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 2 ms/DIV (X), DC range
3. Measurement condition: Just after the ignition switch is off after warm-up (no load)

Scheme 489

1. Terminal connected: 2Y (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 2 ms/DIV (X), DC range
3. Measurement condition: Just after the ignition switch is off after warm-up (no load)

Scheme 490

1. Terminal connected: L/F: 2AA (+)-Negative battery terminal L/R: 2Z (+)-Negative battery terminal T/F: 2AD (+)-Negative battery terminal T/R: 2AC (+)-Negative battery terminal
2. Oscilloscope setting: 2 V/DIV (Y): 10 ms/DIV (X), DC range
3. Measurement condition: Idling after warm-up (no load)

Scheme 491

1. Terminal connected: FP2: 3A (+)-Negative battery terminal RP2: 3D (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 5 ms/DIV (X), DC range
3. Measurement condition: Racing after warm-up (no load)

Scheme 492

1. Terminal connected: 3G (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 20 ms/DIV (X), DC range
3. Measurement condition: Engine speed 6,250 rpm or more after warm-up (approx. 2 s after the APV remains open)

Scheme 493

1. Terminal connected: 3J (+)-Negative battery terminal
2. Oscilloscope setting: 5 V/DIV (Y): 20 ms/DIV (X), DC range
3. Measurement condition: Within 20 s from 2 s after the accelerator is released from the engine speed at 6, 250 rpm or more after warm-up.

NEUTRAL SWITCH INSPECTION

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

Scheme 494

1. Remove the neutral switch.
2. Verify that the continuity between neutral switch terminals 1A and 2A is as indicated in the table. If there is no malfunction, perform the " «CIRCUIT OPEN/SHORT INSPECTION»(ref-221640-S25616859882006022500000) ". If there is any malfunction, replace the neutral switch. NEUTRAL SWITCH SPECIFICATION Measurement condition Continuity Push the rod. No continuity Except above Continuity detected

Scheme 495

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

CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION

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

Scheme 496

1. Remove the CPP switch.
2. Verify that the continuity between CPP switch terminals B and D is as indicated in the table. If there is no malfunction, perform the " «CIRCUIT OPEN/SHORT INSPECTION»(ref-221640-S05530346062006022500000) ". If there is any malfunction, replace the CPP switch. CLUTCH PEDAL POSITION SWITCH SPECIFICATION Measurement condition Continuity Push the rod. No continuity Except above Continuity detected

Scheme 497

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

METERING OIL PUMP SWITCH INSPECTION

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

Voltage Inspection

Note. This inspection procedure is performed using the metering oil pump learning function as one of the PCM learning functions.

1. Make preparations for the PCM terminal voltage measurement. (See «PCM INSPECTION»(ref-221640-S14699949092006022500000) .)
2. To clear the metering oil pump control learning value, disconnect the negative battery terminal.
3. Verify that the voltage at PCM terminal 2N is as indicated in the table. If it cannot be verified even though the related wiring harnesses have no malfunction, replace the metering oil pump. (See «METERING OIL PUMP REMOVAL/INSTALLATION»(ref-221534-S20620648692006022500000) .) PCM TERMINAL 2N SPECIFICATIONS Measurement condition PCM terminal 2N (V) Ignition switch ON 0 Just after engine start B+ Idling after engine start 0

Scheme 498

1. Disconnect the PCM connectors.
2. Disconnect the metering oil pump switch connector.
3. Inspect the following wiring harnesses for open or short circuit. (Continuity inspection)

SECONDARY SHUTTER VALVE (SSV) SWITCH INSPECTION

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

Scheme 499

1. Verify that the continuity between SSV switch terminals A and B is as indicated in the table. If there is no malfunction, perform the " «CIRCUIT OPEN/SHORT INSPECTION»(ref-221640-S25403373392006022500000) ". If there is any malfunction, replace the SSV switch. (See «SECONDARY SHUTTER VALVE (SSV) SWITCH REMOVAL/INSTALLATION»(ref-221640-S23948112252006022500000) .) SECONDARY SHUTTER VALVE SPECIFICATION Measurement condition Continuity Push the rod. No continuity Except above Continuity detected

Scheme 500

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

ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION

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

Resistance Inspection

1. Disconnect the ECT sensor connector.
2. Remove the ECT sensor.
3. Place the detection part of the ECT sensor in water and verify that the resistance between ECT sensor terminals A and B is as indicated in the table while gradually increasing water temperature. If the monitor item condition/specification (reference) is not within the specification, even though the resistance is within the specification, perform the " «CIRCUIT OPEN/SHORT INSPECTION»(ref-221640-S30553153642006022500000) ". If not within the specification, replace the ECT sensor. (See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION»(ref-221640-S11992076472006022500000) .) ECT SENSOR RESISTANCE SPECIFICATION Water temperature (°C {°F}) Resistance (ohm) 20 {68} 2,205-2,695 80 {176} 287-349 91 {196} 227-240

Scheme 501

Scheme 502

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

INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION

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

Scheme 503

1. Disconnect the MAF/IAT sensor connector.
2. Verify that the resistance between MAF sensor terminals D and E is as indicated in the table while blowing hot air gradually into the IAT sensor part built into the MAF sensor. If the monitor item condition/specification (reference) is not within the specification, even though the resistance is within the specification, perform the " «CIRCUIT OPEN/SHORT INSPECTION»(ref-221640-S20092957772006022500000) ". If not within the specification, replace the MAF/IAT sensor. (See «MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION»(ref-221640-S24184145032006022500000) .)

IAT SENSOR RESISTANCE SPECIFICATION

Scheme 504

Scheme 505

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

THROTTLE POSITION (TP) SENSOR INSPECTION

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

1. Turn the ignition switch to the ON position.
2. Verify that the voltage at PCM terminals 1J (WDS PID: TP1) and 1M (WDS PID: TP2) increases while gradually increasing the accelerator pedal opening angle according to the accelerator pedal opening angle. If it can be verified, go to the next step. If it cannot be verified even though the related wiring harnesses have no malfunction, replace the throttle body. (See «INTAKE-AIR SYSTEM REMOVAL/INSTALLATION»(ref-221539-S10926634032006022500000) .)
3. Verify that the voltage at PCM terminals 1J (WDS PID: TP1) and 1M (WDS PID: TP2) is as indicated in the table. If it cannot be verified, replace the throttle body. (See «INTAKE-AIR SYSTEM REMOVAL/INSTALLATION»(ref-221539-S10926634032006022500000) .) TP SENSOR OUTPUT VOLTAGE SPECIFICATION Measurement condition PCM terminal (WDS PID) 1J (TP1) 1M (TP2) When the accelerator pedal is depressed. 3.825-4.095 V 4.033-4.303 V When the accelerator pedal is released. 0.4-0.8 V 1.18-1.78 V

Scheme 506

1. Disconnect the PCM connector.
2. Disconnect the throttle body connector.
3. Inspect the following wiring harnesses for 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 .)

1. Turn the ignition switch to the ON position.
2. Verify that the voltage at PCM terminals 5F (WDS PID: APP1) and 5C (WDS PID: APP2) increases while gradually increasing the accelerator pedal opening angle according to the accelerator pedal opening angle. If it can be verified, go to the next step. If it cannot be verified even though the related wiring harnesses have no malfunction, replace the accelerator pedal.
3. Verify that the voltage at PCM terminals 5F (WDS PID: APP1) and 5C (WDS PID: APP2) is as indicated in the table. If it cannot be verified, replace the accelerator pedal. (See «ACCELERATOR PEDAL REMOVAL/INSTALLATION»(ref-221539-S06520778102006022500000) .) APP SENSOR OUTPUT VOLTAGE SPECIFICATION Measurement condition PCM terminal (WDS PID) 5F (APP1) 5C (APP2) When the accelerator pedal is depressed. 3.78-3.93 V 3.23-3.38 V When the accelerator pedal is released. 1.555-1.655 V 1.005-1.105 V

Scheme 507

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

AUXILIARY PORT VALVE (APV) POSITION SENSOR INSPECTION

Note. To determine if this part has any malfunction, perform the following procedure.

1. Perform the APV motor inspection and replace the APV motor if necessary. (See «AUXILIARY PORT VALVE (APV) MOTOR INSPECTION (13B-MSP (HIGH POWER))»(ref-221539-S38795992242006022500000) .)

Scheme 508

1. Remove the MAF/IAT sensor connector.
2. Remove in the order indicated in the table.
3. Install in the reverse order of removal.

Scheme 509

1. Before installation of the MAF/IAT sensor, replace the O-ring.

MASS AIR FLOW (MAF) SENSOR INSPECTION

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

Visual Inspection

1. Visually inspect the MAF/IAT sensor for the following: Damage, cracks Rusted sensor terminal Bent sensor terminal If there is any malfunction, replace the MAF/IAT sensor. (See «MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION»(ref-221640-S24184145032006022500000) .) If the monitor item condition (reference) is not within the specification even though there is no malfunction, perform the " «CIRCUIT OPEN/SHORT INSPECTION»(ref-221640-S19055077352006022500000) ".

1. Remove the MAF/IAT sensor without disconnect the MAF/IAT sensor connector.
2. Turn the ignition switch to ON position.
3. As the air gradually approaches the MAF detection part of the MAF/IAT sensor, verify that the voltage at PCM terminal 5N (WDS PID: MAF) varies. If it cannot be verified even though the related harnesses have no malfunction, replace the MAF/IAT sensor. (See «MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION»(ref-221640-S24184145032006022500000) .)

AT

MAF SENSOR AT SPECIFICATION

MT

MAF SENSOR MT SPECIFICATION

Scheme 510

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

FRONT HEATED OXYGEN SENSOR (HO2S) INSPECTION

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

Front HO2S Current Inspection

1. Warm up the engine to normal operating temperature.
2. Using the WDS or equivalent, verify that the current of the front HO2S (WDS PID: O2S11) is as indicated in the table. If it cannot be verified even though the related harnesses have no malfunction, replace the front HO2S. (See «FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION»(ref-221640-S18791189262006022500000) .) Front HO2S current FRONT HO2S CURRENT SPECIFICATION Engine condition Current (mA) Accelerated Positive value Decelerated Negative value

Scheme 511

1. Disconnect the front HO2S connector.
2. Measure the resistance between front HO2S terminals C and D. If not within the specification, replace the front HO2S. (See «FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION»(ref-221640-S18791189262006022500000) .) Front HO2S heater resistance 2.16-2.90 ohms [20 °C {68 °F}]

Scheme 512

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

REAR HEATED OXYGEN SENSOR (HO2S) INSPECTION

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

Scheme 513

1. Warm up the engine to normal operating temperature.
2. Disconnect the rear HO2S connector.
3. Connect the positive probe of the tester (digital type) to rear HO2S sensor terminal A, and the negative probe to rear HO2S sensor terminal B and measure the voltage.
4. Maintain the engine speed at 3,000 rpm until the voltage indicates approx. 0.5-0.7 V.
5. Verify that the voltage is as indicated in the table when the engine is raced repeatedly. If it cannot be verified, replace the rear HO2S. (See «REAR HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION»(ref-221640-S06775619452006022500000) .) REAR HO2S VOLTAGE INSPECTION Engine condition Voltage (V) Accelerated 0.5-1.0 Decelerated 0-0.5

Scheme 514

1. Disconnect the rear HO2S connector.
2. Measure the resistance between rear HO2S terminals C and D. If not within the specification, replace the rear HO2S. (See «REAR HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION»(ref-221640-S06775619452006022500000) .) Rear HO2S heater resistance 14.1-18.9 ohms [20 °C {68 °F}]

Scheme 515

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

BAROMETRIC PRESSURE (BARO) SENSOR INSPECTION

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

1. Remove the BARO sensor with the connector still connected.
2. Remove the BARO sensor hose.
3. Turn the ignition switch to the ON position.
4. Verify that the voltage at PCM terminal 5S (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 (See «BAROMETRIC PRESSURE (BARO) SENSOR REMOVAL/INSTALLATION»(ref-221640-S00651972812006022500000) .) BARO sensor output voltage 2.4-4.7 V
5. Install the vacuum pump.
6. Verify that the change in voltage at PCM terminal 5S (WDS PID: BARO) is within the specification when a vacuum of 30 kPa {0.30 kgf/cm 2 , 4.4 psi} is applied. If not within the specification, replace the BARO sensor. (See «BAROMETRIC PRESSURE (BARO) SENSOR REMOVAL/INSTALLATION»(ref-221640-S00651972812006022500000) .) BARO sensor output voltage variance 1.06-1.30 V NOTE: The voltage shown in the figure may vary excessively depending on the weather or battery conditions.

Scheme 516

Scheme 517

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

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

1. Disconnect the KS connector.
2. Measure the resistance between KS terminals A and B. If not within the specification, replace the KS. (See «KNOCK SENSOR (KS) REMOVAL/INSTALLATION»(ref-221640-S21068393932006022500000) .) If the monitor item condition/specification (reference) is not within the specification, even though the KS resistance is within the specification, perform the " «CIRCUIT OPEN/SHORT INSPECTION»(ref-221640-S17017973282006022500000) ". KS resistance 120-280 kilohms

Scheme 518

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

ECCENTRIC SHAFT POSITION SENSOR INSPECTION

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

1. Remove the eccentric shaft position sensor.
2. Verify that there are no metal shavings on the sensor. If the monitor item condition (reference) is not within the specification even though there is no malfunction, perform the " «CIRCUIT OPEN/SHORT INSPECTION»(ref-221640-S28679340912006022500000) ".

1. Disconnect the eccentric shaft position sensor connector.
2. Measure the coil resistance between eccentric shaft position sensor terminals A and B. If not within the specification, replace the eccentric shaft position sensor. If the monitor item condition/specification (reference) is not within the specification, even though the eccentric shaft position sensor resistance is within the specification, perform the " «CIRCUIT OPEN/SHORT INSPECTION»(ref-221640-S28679340912006022500000) " and repair or replace the malfunctioning part. Eccentric shaft position sensor resistance 950-1,250 ohms (at room temperature)

Scheme 519

1. Disconnect the PCM connector.
2. Disconnect the eccentric shaft position sensor connector.
3. Inspect the following wiring harnesses for open or short circuit. (Continuity inspection)