Engine Control System (Aj): Diagnosis Mazda 6 GH

CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION [AJ]

Note. Perform the following inspection only when directed.

Scheme 79

Scheme 80

1. Disconnect the negative battery cable.
2. Remove the clutch switch. (See «CLUTCH PEDAL REMOVAL/INSTALLATION [G35M-R, A65M-R]»(ref-288791-S13123923512008062500000) ).
3. Inspect for continuity between the clutch switch terminals B and D using an ohmmeter. If the clutch switch is okay, but the PID value is out of specification, perform the "Circuit Open/Short Inspection". If not as specified, replace the clutch switch. (See «CLUTCH PEDAL REMOVAL/INSTALLATION [G35M-R, A65M-R]»(ref-288791-S13123923512008062500000) ). Specification

Scheme 81

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [AJ]»(ref-288754-S42604058742008062500000) ).
2. Inspect the following harness for open or short circuit. (Continuity check)

NEUTRAL SWITCH INSPECTION [AJ]

Note. Perform the following inspection only when directed.

Scheme 82

Scheme 83

1. Disconnect the negative battery cable.
2. Remove the neutral switch. (See «NEUTRAL SWITCH REMOVAL/INSTALLATION [A65M-R]»(ref-288787-S00506762402008062500000) ).
3. Inspect for continuity between the neutral switch terminals A and B using an ohmmeter. If the neutral switch is okay, but the PID value is out of specification, perform the "Circuit Open/Short Inspection". If not as specified, replace the neutral switch. (See «NEUTRAL SWITCH REMOVAL/INSTALLATION [A65M-R]»(ref-288787-S00506762402008062500000) ). Specification

Scheme 84

Scheme 85

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [AJ]»(ref-288754-S42604058742008062500000) ).
2. Inspect the following harness for open or short circuit. (Continuity check)

POWER STEERING PRESSURE (PSP) SWITCH INSPECTION [AJ]

Note. Perform the following inspection only when directed.

Scheme 86

Scheme 87

1. Inspect the following if the power steering is inoperative: 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 PSP switch terminal A and body ground using an ohmmeter. If the PSP switch is okay, but the PID value is out of specification, perform the "Circuit Open/Short Inspection". If not as specified, replace the PSP switch. (See «POWER STEERING OIL PUMP REMOVAL/INSTALLATION [AJ]»(ref-288741-S24041522342008062500000) ). Specification

Scheme 88

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [AJ]»(ref-288754-S42604058742008062500000) ).
2. Inspect the following harnesses for open or short circuit. (Continuity check)

ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [AJ]

Note. Perform the following inspection only when directed.

1. Connect the M-MDS to the DLC-2.
2. Turn the ignition switch to ON position.
3. Select APP1 or APP2 PID (percentage) on the M-MDS.
4. Verify that the APP1 or APP2 PID (percentage) changes smoothly while accelerator pedal is gradually depressed. If as verified, go to next step. If not as verified, perform the "Circuit Open/Short Inspection".
5. Verify that the APP1 or APP2 PID (percentage) is as indicated in the table below according to the condition of the accelerator pedal. If not verified, perform the "Circuit Open/Short Inspection". If there is no open or short circuit, replace the APP sensor. (See «ACCELERATOR PEDAL REMOVAL/INSTALLATION [AJ]»(ref-288770-S29955877622008062500000) ).

Specification

SPECIFICATION CONDITION

Scheme 89

Scheme 90

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [AJ]»(ref-288754-S42604058742008062500000) ).
2. Inspect the following harness for open or short circuit. (Continuity check)

THROTTLE POSITION (TP) SENSOR INSPECTION [AJ]

Note. Perform the following inspection only when directed.

Scheme 91

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 [AJ]»(ref-288776-S26157273642008062500000) ).
2. Connect the M-MDS to the DLC-2.
3. Turn the ignition switch to ON position.
4. Select TP1 or TP2 PID (percentage) on the M-MDS.
5. Verify that the TP1 or TP2 PID is within the specification when the accelerator pedal not depressed. (See «PCM INSPECTION [AJ]»(ref-288754-S26268951352008062500000) ).
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". If there is no open or short circuit, replace the throttle body. (See «INTAKE AIR SYSTEM REMOVAL/INSTALLATION [AJ]»(ref-288770-S05460329182008062500000) ).

Scheme 92

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [AJ]»(ref-288754-S42604058742008062500000) ).
2. Inspect the following harnesses for open or short circuit. (Continuity check)

ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [AJ]

Note. Perform the following inspection only when directed.

Scheme 93

1. Remove the ECT sensor. (See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [AJ]»(ref-288754-S11922512032008062500000) ).
2. Place the ECT sensor in water with a thermometer, and heat the water gradually.
3. Measure the resistance between ECT sensor terminals A and B using an ohmmeter. If the ECT sensor is okay, but the PID value is out of specification, perform the "Circuit Open/Short Inspection". If not as specified, replace the ECT sensor. (See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [AJ]»(ref-288754-S11922512032008062500000) ).

Measure the ECT sensor resistance.

ECT SENSOR - RESISTANCE SPECIFICATION

ECT sensor characteristics graph (reference)

Scheme 94

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Scheme 96

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [AJ]»(ref-288754-S42604058742008062500000) ).
2. Inspect the following harnesses, for open or short circuit. (Continuity check)

INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION [AJ]

Note. Perform the following inspection only when directed.

Scheme 97

Scheme 98

1. Disconnect the negative battery cable.
2. Disconnect the MAF/IAT sensor connector.
3. Measure the resistance between the MAF/IAT sensor terminals D and E using an ohmmeter. If the IAT sensor is okay, but the PID value is out of specification, perform the "Circuit Open/Short Inspection". If not as specified, replace the MAF/IAT sensor. (See «INTAKE AIR SYSTEM REMOVAL/INSTALLATION [AJ]»(ref-288770-S05460329182008062500000) ). Specification RESISTANCE SPECIFICATION Ambient temperature (°C {°F}) Resistance (kilohm) -20 {-4} 13.6-18.4 20 {68} 2.21-2.69 60 (140} 0.493-0.667

Scheme 99

Scheme 100

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [AJ]»(ref-288754-S42604058742008062500000) ).
2. Inspect the following harnesses for open or short circuit. (Continuity check)

MASS AIR FLOW (MAF) SENSOR INSPECTION [AJ]

Note. Perform the following inspection only when directed.

Visual Inspection

1. Visually inspect for the following on the MAF/IAT sensor. Damage Cracks Bent terminals Terminal rust If any of the above are found, replace the MAF/IAT sensor. (See «INTAKE AIR SYSTEM REMOVAL/INSTALLATION [AJ]»(ref-288770-S05460329182008062500000) ).

HEATED OXYGEN SENSOR (HO2S) INSPECTION [AJ]

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

Scheme 101

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) HO2S voltage (PID: O2S11/O2S12/O2S21/O2S22)
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 HO2S outputs a voltage of 0.6 V or more, one time or more, then verify that the HO2S voltage (PID: O2S11/O2S12/O2S21/O2S22) 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 «HO2S CIRCUIT OPEN/SHORT INSPECTION (SENSOR)»(ref-288754-S28490995522008062500000) ). Then if there is no malfunction in the wiring harness, replace the HO2S.

Scheme 102

Scheme 103

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

EGR BOOST SENSOR INSPECTION [AJ]

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

Voltage Inspection

1. Connect the M-MDS to the DLC-2.
2. Turn the ignition switch to the ON position.
3. Select BARO PID on the M-MDS.
4. Verify that the BARO PID (pressure) and barometric pressure are practically equal. If verified, go to next step. If not verified, perform the "Circuit Open/Short Inspection". CAUTION: Do not apply vacuum out of specification. Doing so will damage the EGR boost sensor.
5. Apply vacuum of -25.0 kPa {-187 mmHg, -7.38 inHg} to the EGR boost sensor, and verify that the BARO PID variation from that of Step 4 is approx. 25.0 kPa {187 mmHg, 7.38 inHg} . If verified, replace the EGR boost sensor. If not verified, perform the "Circuit Open/Short inspection".

Scheme 104

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [AJ]»(ref-288754-S42604058742008062500000) ).
2. Inspect the following harnesses for open or short circuit. (Continuity check)

KNOCK SENSOR (KS) INSPECTION [AJ]

Note. Perform the following inspection only when directed.

Scheme 105

1. Disconnect the negative battery cable.
2. Disconnect the KS connector.
3. Measure the resistance between KS terminals A and B using an ohmmeter. If the KS is okay, but the PID value is out of specification, perform the "Circuit Open/Short Inspection". If not as specified, replace the KS. (See «KNOCK SENSOR (KS) REMOVAL/INSTALLATION [AJ]»(ref-288754-S07559172422008062500000) ). Specification Approx. 4.87 megohms (20°C {68°F})

Scheme 106

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [AJ]»(ref-288754-S42604058742008062500000) ).
2. Inspect the following harness for open or short circuit. (Continuity check)

CAMSHAFT POSITION (CMP) SENSOR INSPECTION [AJ]

Note. Perform the following inspection only when directed.

Scheme 107

1. Disconnect the negative battery cable.
2. Disconnect the CMP sensor connector.
3. Measure the resistance between the CMP sensor terminals A and B using an ohmmeter. If the CMP sensor is okay, but the PID value is out of specification, perform the "Circuit Open/Short Inspection". If not as specified, replace the CMP sensor. (See «CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [AJ]»(ref-288754-S10635184602008062500000) ). Specification 467-571 ohms

Scheme 108

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [AJ]»(ref-288754-S42604058742008062500000) ).
2. Inspect the following harness for open or short circuit. (Continuity check)

CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [AJ]

Note. Perform the following inspection only when directed.

Scheme 109

1. Disconnect the negative battery cable.
2. Disconnect the CKP sensor connector.
3. Measure the resistance between CKP sensor terminals A and B using an ohmmeter. If the CKP sensor is okay, but the PID value is out of specification, perform the "Circuit Open/Short Inspection". If not as specified, replace the CKP sensor. (See «CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [AJ]»(ref-288754-S31339880822008062500000) ). Specification 267-325 ohms

Scheme 110

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [AJ]»(ref-288754-S42604058742008062500000) ).
2. Inspect the following harness for open or short circuit. (Continuity check)