Mazda 6. Manual — part 133

F–54

CONTROL SYSTEM

— ECT sensor terminal B (harness-side) and power supply

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CRANKSHAFT POSITION (CKP) SENSOR INSPECTION

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Note

• Perform the following inspection only when directed.

Resistance Inspection

1. Disconnect the CKP sensor connector.
2. Measure the resistance between CKP sensor terminals A and B using an ohmmeter.

• If not as specified, replace the CKP sensor.

• If CKP sensor resistance is okay, but RPM PID value is out of specification, perform the “Circuit Open/Short

Inspection”.

Specification

400—550 ohms

Circuit Open/Short Inspection

1. Disconnect the PCM connector. (See

F–43 PCM

REMOVAL/INSTALLATION

.)

2. Inspect the following wiring harnesses for open or

short. (Continuity check)

Open circuit

• If there is no continuity, the circuit is open. Repair

or replace the harness.
— CKP sensor terminal A (harness-side) and

PCM terminal 2D (harness-side)

— CKP sensor terminal B (harness-side) and

PCM terminal 2G (harness-side)

Short circuit

• If there is continuity, the circuit is shorted. Repair

or replace the harness.
— CKP sensor terminal A (harness-side) and power supply
— CKP sensor terminal A (harness-side) and body GND
— CKP sensor terminal B (harness-side) and power supply
— CKP sensor terminal B (harness-side) and body GND

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CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION

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Removal

1. Perform the following procedure to making the working space.

(1) Remove the Front wheel (RH).
(2) Remove the splash shield.

2. Disconnect the CKP sensor connector.
3. Remove the installation bolts to remove the CKP sensor.

Installation

Caution

• When foreign material such as an iron chip is on the CKP sensor, it can cause abnormal output

from the sensor because of flux turbulence and adversely affect the engine control. Be sure there
is no foreign material on the CKP sensor when replacing.

1. Perform the following procedure so that piston No.1 is at the top dead center.

(1) Remove the front driveshaft (RH). (See

M–17 DRIVE SHAFT REMOVAL/INSTALLATION

.)

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F

(2) Remove the cylinder block lower blind plug

and install the SST.

(3) Turn the crankshaft pulley to the clockwise

until it stops.

2. Install the CKP sensor to the CKP sensor

installer.

3. Fit the forked part of the CKP sensor installer with

the ninth tooth (counting counterclockwise from
the empty space) of the pulse wheel.

4. Install the CKP sensor fitting bolts.

Tightening torque

5.5—7.5 N·m {56—76 kgf·cm, 4.1—5.5 ft·lbf}

5. Remove the CKP sensor installer
6. Remove the SST then install the cylinder block lower blind plug.

Tightening torque

20 N·m {2.0 kgf·m, 15 ft·lbf}

7. Install the front driveshaft (RH). (See

M–17 DRIVE SHAFT REMOVAL/INSTALLATION

.)

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CAMSHAFT POSITION (CMP) SENSOR INSPECTION

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Caution

• When foreign material such as an iron chip is on the CMP sensor, it can cause abnormal output

from the sensor because of flux turbulence and adversely affect the engine control. Be sure there
is no foreign material on the CMP sensor when replacing.

Note

• Perform the following inspection only when directed.

Resistance Inspection

1. Disconnect the CMP sensor connector.
2. Measure the resistance between CMP sensor terminals A and B using an ohmmeter.

• If not as specified, replace the CMP sensor.

• If CMP sensor resistance is okay, perform the “Circuit Open/Short Inspection”.

Specification

400—550 ohms

Circuit Open/Short Inspection

1. Disconnect the PCM connector. (See

F–43 PCM

REMOVAL/INSTALLATION

.)

2. Inspect the following wiring harnesses for open or

short. (Continuity check)

Open circuit

• If there is no continuity, the circuit is open. Repair

or replace the harness.
— CMP sensor terminal A (harness-side) and

PCM terminal 2M (harness-side)

— CMP sensor terminal B (harness-siede) and

PCM terminal 2J (harness-side)

Short circuit

• If there is continuity, the circuit is shorted. Repair

or replace the harness.
— CMP sensor terminal A (harness-side) and power supply
— CMP sensor terminal A (harness-side) and body GND
— CMP sensor terminal B (harness-side) and power supply
— CMP sensor terminal B (harness-side) and body GND

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CONTROL SYSTEM

KNOCK SENSOR INSPECTION

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Note

• Perform the following test only when directed.

Resistance Inspection

1. Turn the ignition switch to LOCK.
2. Disconnect the knock sensor connector.
3. Measure the resistance between the knock sensor terminals A and B using an ohmmeter.

• If not as specified, replace the knock sensor.

• If the knock sensor is okay, but PID value is out of specification, perform the “Circuit Open/Short

Inspection”.

Specification

Approx. 4.87 megohms

Circuit Open/Short Inspection

1. Disconnect the PCM connector. (See

F–43 PCM

REMOVAL/INSTALLATION

.)

2. Inspect the following wiring harnesses for open or

short. (Continuity check)

Open circuit

• If there is no continuity, the circuit is open. Repair

or replace the harness.
— Knock sensor terminal A (harness-side) and

PCM terminal 2S (harness-side)

— Knock sensor terminal B (harness-side) and

PCM terminal 2P (harness-side)

Short circuit

• If there is continuity, the circuit is shorted. Repair

or replace the harness.
— Knock sensor terminal A (harness-side) and power supply
— Knock sensor terminal A (harness-side) and body GND
— Knock sensor terminal B (harness-side) and power supply
— Knock sensor terminal B (harness-side) and body GND

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KNOCK SENSOR REMOVAL/INSTALLATION

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1. Remove the intake manifold. (See

F–10 INTAKE-AIR SYSTEM REMOVAL/INSTALLATION

.)

2. Remove the knock sensor attachment bolt to

remove the knock sensor.

3. Install in the reverse order of removal.

Tightening torque

16.2—23.8 N·m

{1.66—2.42 kgf·m, 12.0—17.5 ft·lbf}

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HEATED OXYGEN SENSOR (HO2S) INSPECTION

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HO2S Voltage Inspection

Note

• Perform the following inspection only when directed.

1. Warm up the engine and run it at idle.
2. Disconnect the HO2S connector.

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3. Connect the voltmeter test leads to the following

HO2S terminals:

• HO2S (front and rear)

— (+) lead—terminal A
— (–) lead—terminal B

4. With the vehicle stopped, run the engine at 3,000

rpm until the voltmeter moves between 0.5 and
0.7 V.

5. Verify that the measurement voltage changes

when the engine speed increases and decreases
suddenly several times.

• If not as specified, replace the HO2S.

• If the HO2S is okay, but O2S11 or O2S12 PID

value is out of specification, perform the
“Circuit Open/Short Inspection”.

Specification

Circuit Open/Short Inspection (Sensor)

1. Disconnect the PCM connector. (See

F–43 PCM

REMOVAL/INSTALLATION

.)

2. Inspect the following wiring harnesses for open or

short. (Continuity check)

Open circuit

• If there is no continuity, the circuit is open. Repair

or replace the harness.
Front
— HO2S terminal A (harness-side) and PCM

terminal 1AB (harness-side)

— HO2S terminal B (harness-side) and PCM

terminal 2H (harness-side)

Rear
— HO2S terminal A (harness-side) and PCM

terminal 1Y (harness-side)

— HO2S terminal B (harness-side) and PCM terminal 2H (harness-side)

Short circuit

• If there is continuity, the circuit is shorted. Repair or replace the harness.

Front and Rear
— HO2S terminal A (harness-side) and body GND
— HO2S terminal A (harness-side) and power supply
— HO2S terminal B (harness-side) and power supply

HO2S Heater Resistance Inspection

1. Disconnect the HO2S connector.
2. Measure the resistance between the HO2S

terminals C and D.

• If not as specified, replace the HO2S.

• If the HO2S heater is okay, but PID value is

out of specification, perform the “Circuit Open/
Short Inspection”.

Specification

Front : 3.0—3.6 ohms
Rear : 5—7 ohms

Engine speed

Voltage (V)

Acceleration

0.5—1.0

Deceleration

0—0.5

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