Mazda CX 7. Manual - part 97

 

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Mazda CX 7. Manual - part 97

 

 

SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–85

01-03

Fuel Cut Control System Inspection

Note

• This inspection has to be performed after the Fuel Injector Operation Inspection.

If simulation function of M-MDS is used:

1. Warm up the engine and idle it.
2. Connect the M-MDS to the DLC-2.
3. Select the RPM and the FUELPW1 PIDs.
4. Monitor both PIDs while performing the following steps.

(1) Depress the accelerator pedal and increase the RPM PID to 4,000 rpm.
(2) Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the FUELPW1 PID is 0 

msec., and 2— 5 msec. when the RPM PID drops below 1,200 rpm.

• If not as specified, inspect the following.

— ECT sensor and related wiring harness

(See01-40-25 ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION[L3 WITH TC].)

If simulation function of M-MDS is not used:

1. Warm up the engine and idle it.
2. Measure the fuel injector control signal wave profile using the oscilloscope while performing the following steps.

(1) Depress the accelerator pedal and increase the engine speed to 4,000 rpm.
(2) Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the wave profile 

constantB+, and the wave appears when the engine speed drops below 1,200 rpm.
(See01-40-6 PCM INSPECTION[L3 WITH TC].)

• If not as specified, inspect the following.

— ECT sensor and related wiring harness

(See01-40-25 ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION[L3 WITH TC].)

Fuel Pump Operation Inspection
If simulation function of M-MDS is not used:

1. Connect the M-MDS to the DLC-2.
2. Remove the fuel-filler cap.
3. Turn the ignition switch to the ON position.
4. Turn the fuel pump relay from off to on using the FP PID and inspect if the operation sound of the fuel pump is 

heard.

• If no operation sound is heard, proceed to the next step.

5. Measure the voltage at the wiring harness side fuel pump connector terminal B with the FIP PID turned on.

• If the voltage is as specified, inspect the following:

— Fuel pump continuity

— Fuel pump ground

— Wiring harness between the fuel pump relay and PCM terminal 1H

• If not as specified, inspect the following:

— Fuel pump relay

— Fuel pump speed control relay

— Wiring harness connector (Main relay—fuel pump relay—fuel pump resister—fuel pump.)

Specification

8.0— 11.5 V (Ignition switch at ON)

If simulation function of M-MDS is not used:

Caution

• Connecting the wrong check connector terminal may possibly cause a malfunction. Carefully 

connect the specified terminal only.

1. Short the check connector terminal F/P to body ground using a jumper wire.
2. Remove the fuel-filler cap.
3. Turn the ignition switch to the ON position.
4. Verify that the fuel pump operation sound is heard.

• If no operation sound is heard, proceed to the next step.

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SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–86

5. Measure the voltage at wiring harness side fuel pump connector terminal B.

• If the voltage is as specified, inspect the following:

— Fuel pump continuity

— Fuel pump ground

— Wiring harness between the fuel pump relay and PCM terminal, 1H

• If not as specified, inspect the following:

— Fuel pump relay

— Fuel pump speed control relay

— Wiring harness connector (Main relay—fuel pump relay—fuel pump resister—fuel pump.)

Specification

8.0— 11.5 V (Ignition switch at on)

Fuel Pump Control System Inspection
If simulation function of M-MDS is used:

1. Connect the M-MDS to the DLC-2.
2. Turn the ignition switch to the ON position.
3. Select the FP PID.
4. Turn the fuel pump relay from off to on and inspect if the operation sound of the fuel pump relay is heard.

• If no operation sound is heard, inspect the fuel pump relay.

• If the fuel pump relay is normal, inspect the following:

— Wiring harness and connectors (Main relay—fuel pump relay—PCM terminal 1H)

If simulation function of M-MDS is not used:

1. Crank the engine and verify that the fuel pump relay operation sound is heard.
2. If the operation sound is not heard, inspect the following:

• Fuel pump relay

• Wiring harness and connectors (Main relay—fuel pump relay—PCM terminal 1H)

Fuel Pump Speed Control Inspection
If simulation function of M-MDS is used:

1. Perform the Fuel Pump Operation Inspection.
2. Connect the M-MDS to the DLC-2.
3. Turn the ignition switch to the ON position.
4. Turn the fuel pump speed control relay from off to on using the FPRR PID and verify that the fuel pump speed 

control relay operation sound is heard.

• If the operation sound is not heard, inspect the following:

— Fuel pump speed control relay

— Wiring harness and connectors (Main relay—fuel pump speed control relay—PCM terminal 1AA)

5. Start the engine and run it is idling.
6. Remove the fuel-filler cap.
7. Turn the fuel pump speed control relay from off to on using the FPRR PID and inspect if the operation sound 

frequency of the fuel pump is higher than when the FPRR PID is off.

• If it cannot be verified, inspect the following:

— Fuel pump resister

— Wiring harness and connectors (open circuit at fuel pump speed control relay terminal C—fuel pump 

relay terminal D)

If simulation function of M-MDS is not used:

1. Perform the fuel pump operation inspection.
2. Verify that fuel pump relay operation sound is heard, while cranking the engine.

• If the operation sound is not heard, inspect the following:

— Fuel pump relay

— Wiring harnesses and connectors (Main relay— fuel pump relay— PCM terminal 1H)

3. Remove the fuel-filler cap.
4. Verify that the fuel pump unit operation sound frequency at cranking is higher than during idle.

• If it cannot verified, inspect for the following:

— Fuel pump resister

— Fuel pump relay

— Wiring harnesses and connectors (open circuit at fuel pump relay terminal C— fuel pump terminal B)

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SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–87

01-03

2007 Mazda CX-7 Workshop Manual (1871–1U–06B)

Revised 8/2006 (Ref. No. R087/06) 

Spark Test

1. Disconnect the fuel pump relay.
2. Verify that each ignition coil and connector is connected properly.
3. Inspect the ignition system in the following procedure.

Warning

• High voltage in the ignition system can cause strong electrical shock which can result in serious 

injury. Avoid direct contact to the vehicle body during the following spark test.

EGR Control System Inspection
If simulation function of M-MDS is used:

1. Crank the engine and verify that the EGR valve operation (initial operation) sound is heard.

• If the operation sound is not heard, connect the M-MDS to the DLC-2 and verify that the DTC P0403 is 

shown. Perform the DTC inspection. (See01-02-13 DTC TABLE[L3 WITH TC].)

2. Start the engine run it is idling.
3. Increase the step value of the EGR valve from 0 to 57 using the SEGR PID of the simulation function.
4. Operate the EGR valve and inspect if the engine speed becomes unstable or the engine stalls.

• If the engine speed does not change, proceed to the following.

(1) Stop the engine.
(2) Remove the EGR valve.
(3) Connect the EGR valve connector.
(4) Turn the ignition switch to the ON position.
(5) Increase the step value of EGR valve from 0 to 57 using SEGRP PID.
(6) Verify that the EGR valve operates according to the SEGRP PID.

• If the EGR valve is operated, clean the EGR valve and the EGR gas passage.

• If the EGR valve does not operate, replace the EGR valve.

5. Start the engine and warm it up completely.
6. Access the following PIDs.

• ECT, RPM, SEGRP, APP1, APP2, TP_REL, VSS

7. Idle the vehicle and verify that the SEGRP value is 0.

STEP

INSPECTION

ACTION

1

• Disconnect the ignition coil from the spark 

plugs.

• Remove the spark plugs.

• Verify that the spark plugs do not have 

carbon deposits.

• Are the spark plugs normal?

Yes

Go to the next step.

No

Perform no-load racing at 4,000 rpm for 2 min, 2 times to 
burn off the carbon deposits.
Repeat Step 1.

2

• Inspect the spark plugs for damage, wear, 

and proper plug gap.

• Are the spark plugs normal?

Yes

Go to the next step.

No

Replace spark plugs, then go to the next step.

3

• Reconnect the spark plugs to the ignition 

coil.

• Ground the spark plugs to the engine.

• Is a strong blue spark visible at each cylinder 

while cranking the engine?

Yes

Ignition system is normal.

No

Some cylinders do not spark: 

• Go to the next step.

All cylinders do not spark: 

• Go to Step 5.

4

• Inspect the following wiring harnesses for an 

open or short circuit:

— Ignition coil No.1 terminal C—PCM 

terminal 2BA

— Ignition coil No.2 terminal C—PCM 

terminal 2AW

— Ignition coil No.3 terminal C—PCM 

terminal 2AX

— Ignition coil No.4 terminal C—PCM 

terminal 2AT

• Are the wiring harnesses normal?

Yes

Inspect and replace the ignition coil.
 (See01-18-2 IGNITION COIL INSPECTION[L3 WITH TC].)

No

Repair or replace the malfunctioning part, then go to Step 1.

5

• Measure the voltage at terminal A in each 

ignition coils.

• Is the voltage B+?

Yes

Go to the next step.

No

Inspect the power supply circuit of ignition coils.

6

• Does the PCM connector or ignition coil 

connectors have poor connection?

Yes

Repair or replace the connector, then go to Step 1.

No

Go to the next step.

7

• Are the following parts normal?

— CKP sensor and crankshaft pulley

Yes

Inspect for an open or short circuit in the wiring harness and 
connector of the CKP sensor.

No

Repair or replace the malfunctioning part, then go to Step 1.

SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–88

2007 Mazda CX-7 Workshop Manual (1871–1U–06B)

8. Put the vehicle in drive.
9. Depress the accelerator pedal and verify that the SEGRP value increases.

• If the SEGRP value does not increase, inspect the VSS, TP and ECT PIDs. (See01-40-6 PCM 

INSPECTION[L3 WITH TC].)

10. Stop the vehicle and verify that the SEGRP value is returns to 0.

If simulation function of M-MDS is not used:

1. Verify that EGR valve operation (initial operation) sound is heard when the ignition switch is turned to the ON 

position.

• If the operation sound is not heard, connect the M-MDS to the DLC-2 and verify that the DTC P0403 is 

shown. Perform the DTC inspection. (See01-02-13 DTC TABLE[L3 WITH TC].)

2. Start the engine and idle it.
3. Warm up the engine to normal operating temperature.
4. Select the following PIDs:

• ECT, RPM, SEGRP, APP1, APP2, TP_REL, VSS

5. Let the vehicle idle and verify that the SEGRP value is 0.
6. Put the vehicle in drive.
7. Depress the accelerator pedal and verify that the SEGRP value is increased.

• If the EGR valve increases, inspect the following:

— EGR valve (stuck open or closed)

— Wiring harness and connectors (Main relay—EGR valve—PCM)

• If the SEGRP value does not increase, inspect the VSS, APP1, APP2, TP_REL and ECT PIDs. (See01-40-

6 PCM INSPECTION[L3 WITH TC].)

8. Stop the vehicle and verify that the SEGRP value returns to 0.

Purge Control System Inspection
If simulation function of M-MDS is used:

1. Start the engine.
2. Disconnect the vacuum hose between the purge solenoid valve and the charcoal canister.
3. Put a finger to the purge solenoid valve and verify that there is no vacuum applied when the engine is cold.

• If there is a vacuum, inspect the following:

— Wiring harness and connectors (Purge solenoid valve—PCM terminal 2AB)

— Purge solenoid valve (stuck open)

4. Connect the M-MDS to the DLC-2 and verify that the DTC P0403 is displayed. Perform the DTC inspection.

(See01-02-133 DTC P0403[L3 WITH TC].)

5. Select the EVAPCP PID.
6. Increase the duty value of the purge solenoid valve to 50% and inspect if the operation sound of the valve is 

heard.

• If the operation sound is heard, inspect for loose or damaged vacuum hoses. (Intake manifold—purge 

solenoid valve—charcoal canister)

• If the operation sound is not heard, perform the purge solenoid valve inspection. (See01-16-9 PURGE 

SOLENOID VALVE INSPECTION[L3 WITH TC].)

7. Warm up the engine to normal operating temperature.
8. Monitor the EVAPCP PID using the M-MDS, and drive the vehicle approx. 2000 rpm for 30 s or more.

• If the EVAPCP PID is 0%, inspect the following.

— MAF, APP1, APP2, TP_REL and LOAD PIDs.

If simulation function of M-MDS is not used:

1. Start the engine.
2. Disconnect the vacuum hose between the purge solenoid valve and the charcoal canister.
3. Put a finger to the purge solenoid valve and verify that there is no vacuum applied when the engine is cold.

• If there is vacuum, inspect the following:

— Wiring harness and connectors (Purge solenoid valve—PCM terminal, 2AB)

— Purge solenoid valve

4. Warm up the engine to the normal operating temperature.
5. Stop the engine.
6. Connect the M-MDS to the DLC-2 and verify that the DTC P0443 is shown. Perform DTC inspection. (See01-

02-13 DTC TABLE[L3 WITH TC].)

7. Turn the ignition switch to the ON position.
8. Select the ECT PID.
9. Verify that the engine coolant temperature is above 60

°C {140°F}.

• If the M-MDS indicates that the temperature is below 60°C {140°F}, perform the ECT sensor inspection.

 

 

 

 

 

 

 

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