Engine Control System (MZI-3.7): Diagnosis Mazda CX-9 I

PCM INSPECTION [MZI-3.7]

PCM Inspection Preparation

1. Disconnect the negative battery cable.
2. Remove the battery and battery tray. See «BATTERY REMOVAL/INSTALLATION [MZI-3.7]»(ref-345358-S08633229842009102000000) .
3. Remove the windshield wiper arm and blade. See «WINDSHIELD WIPER ARM AND BLADE REMOVAL/INSTALLATION»(ref-345367-S20259665782009102000000) .
4. Remove the cowl grille. See «COWL GRILLE REMOVAL/INSTALLATION»(ref-345340-S17876884912009102000000) .
5. Remove the windshield wiper motor. See «WINDSHIELD WASHER MOTOR REMOVAL/INSTALLATION»(ref-345367-S20390065822009102000000) .
6. Remove the cowl panel. See «COWL PANEL REMOVAL/INSTALLATION»(ref-345365-S22373951532009102000000) .
7. Remove the PCM connector still connected.
8. Install the battery and battery tray. See «BATTERY REMOVAL/INSTALLATION [MZI-3.7]»(ref-345358-S08633229842009102000000) .
9. Connect the negative battery cable.

Scheme 6

VOLTAGE SENSOR SPECIFICATION CHART

VOLTAGE SENSOR SPECIFICATION CHART

VOLTAGE SENSOR SPECIFICATION CHART

Continuity Inspection

1. Disconnect the PSP switch connector.
2. Start the engine.
3. Verify no continuity between the PSP switch terminals while rotating the steering wheel. If there is continuity, verify that P/S oil pump is normal and replace the PSP switch. See «POWER STEERING OIL PUMP DISASSEMBLY/ASSEMBLY»(ref-345338-S37792283192009102000000) . If the monitor item condition/specification (reference) is not within the specification, even though there is no malfunction, perform the "Circuit Open/Short Inspection".

Scheme 7

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Inspect the following wiring harness for open or short. (Continuity inspection)

MASS AIR FLOW (MAF) SENSOR INSPECTION [MZI-3.7]

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

Visual Inspection

1. Verify the following items of the MAF sensor. Damage, cracks Rusted sensor terminal Bent sensor terminal If there is any malfunction, replace the MAF sensor. See «MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S38494331652009102000000) .

Voltage Inspection

1. Remove the MAF sensor with the connector still connected.
2. Turn the ignition switch to the ON position.
3. Verify that the MAF sensor output voltage (M-MDS monitor item: MAF) changes when wind is introduced gradually to the sensor part of the MAF sensor. If it cannot be verified even though the related harnesses have no malfunction, replace the MAF sensor. See «MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S38494331652009102000000) . 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".

Scheme 8

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Disconnect the MAF/IAT sensor connector.
3. Inspect the following wiring harnesses for open or short. (Continuity inspection)

INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION [MZI-3.7]

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

Scheme 9

Scheme 10

1. Disconnect the MAF/IAT sensor connector.
2. Measure the resistance between MAF/IAT sensor terminals A and F. If not within the specification, replace the MAF/IAT sensor. See «MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S38494331652009102000000) . 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". IAT sensor resistance IAT SENSOR RESISTANCE SPECIFICATION CHART IAT (°C {°F}) Resistance (kilohm) 10(50} Approx. 58.75 20 {68} Approx. 37.30 30 {86} Approx. 24.27 60 {140} Approx. 7.70 IAT sensor characteristics graph (reference)

Scheme 11

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Inspect the following wiring harnesses for open or short. (Continuity inspection)

THROTTLE POSITION (TP) SENSOR INSPECTION [MZI-3.7]

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

Scheme 12

Scheme 13

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 [MZI-3.7]»(ref-345342-S02066164152009102000000) .
2. Connect the M-MDS to the DLC-2.
3. Turn the ignition switch to the ON position.
4. Select TP1 or TP2 PID (voltage) on the M-MDS.
5. Operate the accelerator pedal and verify that the TP1 or TP2 PID (voltage) 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 [MZI-3.7]»(ref-345348-S33859003282009102000000) .

Scheme 14

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Inspect the following wiring harnesses for open or short circuit. (Continuity inspection)

ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI-3.7]

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

Scheme 15

1. Turn the ignition switch to the ON position (Engine OFF).
2. Verify that the PCM terminal 1 AC, 1 AG and 1 AK 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.
3. Verify that the PCM terminal 1 AC, 1 AG and 1 AK voltages are as shown in the following table. If voltage is not as following table, perform the "Circuit Open/Short Inspection". If there is no open or short circuit, replace accelerator pedal. See «ACCELERATOR PEDAL REMOVAL/INSTALLATION [MZI-3.7]»(ref-345348-S02009292962009102000000) . APP sensor output voltage APP SENSOR OUTPUT VOLTAGE SPECIFICATION CHART Condition PCM terminal 1AK (APP sensor No. 1) PCM terminal 1AG (APP sensor No. 2) PCM terminal 1 AC (APP sensor No. 3) Accelerator pedal released Approx. 4.1 V Approx. 1.5 V Approx. 0.1 V Accelerator pedal depressed Approx. 1.0 V Approx. 3.9 V Approx. 3.3 V

Scheme 16

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Inspect the following wiring harnesses for open or short circuit. (Continuity inspection)

CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI-3.7]

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

1. Remove the CKP sensor. See «CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S08254603612009102000000) .
2. Verify that there are no metal shavings on the CKP sensor.
3. Install the CKP sensor. See «CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S08254603612009102000000) .

Resistance Inspection

1. Remove the CKP sensor connector.
2. Measure the resistance between the CKP sensor terminals. If not within the specification, replace the CKP sensor. See «CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S08254603612009102000000) . 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". CKP sensor resistance 250-1,000 ohms

Scheme 17

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Inspect the following harness for open or short circuit. (Continuity check)

CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7]

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

1. Remove the CMP sensor. See «CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S01563065562009102000000) .
2. Verify that there are no metal shavings on the CMP sensor.
3. Install the CMP sensor. See «CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S01563065562009102000000) .

1. Remove the CMP sensor connector.
2. Measure the resistance between the CMP sensor terminals. If not within the specification, replace the CMP sensor. See «CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S01563065562009102000000) . 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". CMP sensor resistance 800-1,320 ohms

Scheme 18

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Inspect the following harness for open or short circuit. (Continuity check)

FRONT HEATED OXYGEN SENSOR (HO2S) INSPECTION [MZI-3.7]

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

Scheme 19

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) Front HO2S voltage (PID: O2S11, O2S21)
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 front H02S outputs a voltage of 0.6 V or more , one time or more, then verify that the front HO2S voltage (PID: O2S11, O2S21) is 0.3 V is or less while decelerating as shown in the figure. If not within the specification, inspect the front HO2S for an open or short circuit. See «FRONT HEATED OXYGEN SENSOR (HO2S»(ref-345345-S08645673222009102000000) ) Voltage Inspection. Then if there is no malfunction in the wiring harness, replace the front HO2S. See «FRONT HEATED OXYGEN SENSOR (HO2S»(ref-345345-S08645673222009102000000) ) REMOVAL/INSTALLATION [MZI-3.7].

Scheme 20

1. Disconnect the HO2S connector.
2. Measure the resistance between HO2S terminals C and A. If it is not within the specification, replace the HO2S. See «FRONT HEATED OXYGEN SENSOR (HO2S»(ref-345345-S08645673222009102000000) ) REMOVAL/INSTALLATION [MZI-3.7]. 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". HO2S heater resistance 3-30 ohms

Scheme 21

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Inspect the following wiring harness for open or short (continuity check).

REAR HEATED OXYGEN SENSOR (HO2S) INSPECTION [MZI-3.7]

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

Scheme 22

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) Rear HO2S voltage (PID: O2S12, 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 rear HO2S outputs a voltage of 0.6 V or more , one time or more, then verify that the rear HO2S voltage (PID: O2S12, O2S22) is 0.3 V is or less while decelerating as shown in the figure. If not within the specification, inspect the rear HO2S for an open or short circuit. Then if there is no malfunction in the wiring harness, replace the rear HO2S. See «REAR HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13313935082009102000000) .

Scheme 23

1. Disconnect the HO2S connector.
2. Measure the resistance between HO2S terminals C and A. If it is not within the specification, replace the HO2S. See «REAR HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13313935082009102000000) . 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". HO2S heater resistance 3-30 ohms

Scheme 24

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Inspect the following wiring harness for open or short (continuity check).

KNOCK SENSOR (KS) INSPECTION [MZI-3.7]

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

1. Turn the ignition switch to LOCK.
2. Disconnect the KS connector.
3. Measure the resistance between the KS terminals. KS(RH): KS terminals A and B KS(LH): KS terminals C and D If not as specified, replace the KS. If the KS is normal, but PID value is out of specification, perform the "Circuit Open/Short Inspection". KS resistance 4.39-5.35 Mohms

Scheme 25

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Inspect the following wiring harnesses for open or short. (Continuity inspection)

CYLINDER HEAD TEMPERATURE (CHT) SENSOR INSPECTION [MZI-3.7]

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

Scheme 26

1. Disconnect the CHT sensor connector.
2. Measure the resistance between the CHT sensor terminals. If it is not within the specification, replace the CHT 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". Measure the cylinder head temperature sensor resistance (approx.. RESISTANCE SPECIFICATION CHART Cylinder head temperature (°C {°F}) Resistance (kilohm) 20 {68} 37.387 80 {176} 3.775 Cylinder head temperature sensor characteristics graph (reference)

Scheme 27

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Inspect the following wiring harnesses for open or short. (Continuity inspection)

1. Remove the evaporative hose component. See «FUEL TANK REMOVAL/INSTALLATION [MZI-3.7]»(ref-345350-S32203684872009102000000) .
2. Turn the ignition switch to the ON position.
3. Plug one end of the evaporative hose component and verify that the output voltage from the fuel tank pressure sensor changes when pressure is applied from the other hose end. If it cannot be verified even though the related harnesses have no malfunction, replace the evaporative hose component. See «FUEL TANK REMOVAL/INSTALLATION [MZI-3.7]»(ref-345350-S32203684872009102000000) . 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".

Scheme 28

1. Disconnect the PCM connector. See «PCM REMOVAL/INSTALLATION [MZI-3.7]»(ref-345345-S13054837012009102000000) .
2. Disconnect the fuel tank pressure sensor connector.
3. Inspect the following wiring harnesses for open or short. (Continuity inspection)