Symptom Troubleshooting - Engine: Diagnosis Mazda 3 BK

INSPECTION METHOD FOR SENSORS

1. Connect the WDS or equivalent to the DLC-2.
2. Turn the ignition switch to the ON position (Engine off).
3. Access PIDs for the switch you are inspecting.
4. Vibrate the sensor slightly with your finger. If PID value is unstable or malfunction occurs, check for poor connection or poorly mounted sensor or both.

INSPECTION METHOD FOR ACTUATORS OR RELAYS

1. Connect the WDS or equivalent to the DLC-2.
2. Turn the ignition switch to the ON position (Engine off).
3. Prepare the output state control function for actuators or relays that you are inspecting.
4. Vibrate the actuator or relay with your finger for 3 s after output state control function is activated. If variable click sound is heard, check for poor connection or poorly mounted actuator or both, or the relay.

ENGINE SYMPTOM TROUBLESHOOTING

1. Confirm trouble symptom using the following diagnostic index, then go to appropriate troubleshooting chart.

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INPUT SIGNAL SYSTEM INSPECTION PROCEDURE

1. Find an irregular signal. (See «FINDING IRREGULAR SIGNALS»(ref-177559-S28095488852005060200000) .)
2. Locate source. (See «LOCATING THE SOURCE OF UNUSUAL SIGNALS»(ref-177559-S20090342982005060200000) .)
3. Repair or replace the malfunctioning part.
4. Confirm that the irregular signal is no longer detected.

INPUT SIGNAL SYSTEM INSPECTION FOR VARIABLE RESISTANCE TYPE 1

1. When an irregular signal is detected, measure the #1 PCM terminal voltage. If the #1 terminal voltage and the WDS or equivalent monitor voltage are the same, proceed to the next step. If there is a difference of 0.5 V or more , inspect for the following points concerning the PCM connector: Female terminal opening is loose. Coupler (pin holder) damage. Pin discoloration (blackness). Harness/pin crimp is loose or disconnected.
2. Measure the #2 sensor terminal voltage: If there is a 0.5 V or more difference between the sensor and the WDS or equivalent voltages, inspect the wiring harness for open or short circuits. If the sensor and the WDS or equivalent voltages are the same, inspect for the following points concerning the sensor connector: Female terminal opening is loose. Coupler (pin holder) damage. Pin discoloration (blackness). If there are no problems, proceed to next investigation below.

STANDARD POWER SUPPLY SYSTEM INSPECTION FOR VARIABLE RESISTANCE TYPE 1

1. Confirm that the #3 terminal is at 5 V . If the measured voltage on the #3 terminal is 5 V , inspect the following points on the sensor connector. If there is no problem, inspect for the following: Female terminal opening is loose. Coupler (pin holder) damage. Pin discoloration (blackness). If the #3 terminal measures other than 5 V , inspect for the following: Open or short circuit in wiring harness. Harness/pin crimp is loose or disconnected.

GND SYSTEM INSPECTION FOR VARIABLE RESISTANCE TYPE 1

1. Confirm that terminal sensor #5 is at 0 V . If it is at 0 V , inspect the sensor. If necessary, replace the sensor. If not, inspect for the following: Open or short circuit in wiring harness. Female terminal opening is loose causing an open or short circuit in wiring harness. Coupler (pin holder) damage. Pin discoloration (blackness). Harness/pin crimp is loose or disconnected.

Scheme 519

GND SYSTEM INSPECTION FOR VARIABLE RESISTANCE TYPE 2

1. Confirm that terminal sensor #4 is at 0 V . If it is at 0 V , inspect the sensor. If necessary, replace the sensor. If not at 0 V , inspect for the following: Open circuit in wiring harness. Female terminal opening is loose. Coupler (pin holder) damage. Pin discoloration (blackness). Harness/pin crimp is loose or disconnected.

INPUT SIGNAL SYSTEM INSPECTION FOR VARIABLE RESISTANCE TYPE 2

1. When an irregular signal is detected, measure the #1 PCM terminal voltage. If the #1 terminal voltage and the WDS or equivalent monitor voltage are the same, proceed to the next step. If there is a difference of 0.5 V or more , inspect for the following points concerning the PCM connector: Female terminal opening is loose. Coupler (pin holder) damage. Pin discoloration (blackness). Harness/pin crimp is loose or disconnected.
2. Measure the #2 sensor terminal voltage. If there is a 0.5 V or more difference between the sensor and the WDS or equivalent voltages, inspect the wiring harness for open or short circuits. If the sensor and the WDS or equivalent voltages are the same, inspect the following points concerning the sensor connector: Female terminal opening is loose. Coupler (pin holder) damage. Pin discoloration (blackness). Harness/pin crimp is loose or disconnected. If there are no problems, proceed to next investigation below.

ELECTRICAL SUPPLY SYSTEM INSPECTION FOR VARIABLE RESISTANCE TYPE 2

1. Confirm that the sensor #3 terminal is B+ . If the measured voltage on the #3 terminal is B+ , inspect the following points on the sensor connector. If there is no problem, inspect for the following: Female terminal opening is loose. Coupler (pin holder) damage. Pin discoloration (blackness). If the #3 terminal measures other than B+ , inspect the following: Open or short circuit in wiring harness. Harness/pin crimp is loose or disconnected.

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INPUT SIGNAL SYSTEM INSPECTION FOR THERMISTOR TYPE

1. When an irregular signal is detected, measure the #1 PCM terminal voltage. If the #1 terminal voltage and the WDS or equivalent monitor voltage are the same, proceed to the next step. If there is a difference of 0.5 V or more , inspect the following points concerning the PCM connector: Female terminal opening loose. Coupler (pin holder) damage. Pin discoloration (blackness). Harness/pin crimp is loose or disconnected.
2. Measure the #2 sensor terminal voltage. If there is a 0.5 V or more difference between the sensor and the WDS or equivalent voltages, inspect the wiring harness for open or short circuits. If the sensor and the WDS or equivalent voltages are the same, inspect the following points concerning the sensor connector: Female terminal opening is loose. Coupler (pin holder) damage. Pin discoloration (blackness). Harness/pin crimp is loose or disconnected. If there are no problems, proceed to next investigation. See «GND SYSTEM INSPECTION FOR THERMISTOR TYPE»(ref-177559-S24213566022005060200000) .

GND SYSTEM INSPECTION FOR THERMISTOR TYPE

1. Confirm that terminal sensor #3 is at 0 V . If it is at 0 V , inspect the sensor. If necessary, replace the sensor. If not, inspect for the following: Open circuit in wiring harness. Female terminal opening is loose. Coupler (pin holder) damage. Pin discoloration (blackness). Harness/pin crimp is loose or disconnected.

INTAKE MANIFOLD VACUUM INSPECTION

1. Verify air intake hoses are installed properly.
2. Start the engine and run it at idle.
3. Disconnect the vacuum hose between the intake manifold and purge solenoid valve from the intake manifold side.
4. Connect a vacuum gauge to the intake manifold and measure the intake manifold vacuum. If not as specified, inspect the following: Specification (LF) ATX: More than 55 kPa {413 mmHg, 16 inHg} MTX: More than 57 kPa {428 mmHg, 17 inHg} Specification (L3) ATX: More than 57 kPa {428 mmHg, 17 inHg} MTX: More than 60 kPa {451 mmHg, 18 inHg} NOTE: Air suction can be located by engine speed change when lubricant is sprayed on the area where suction is occurring. Air suction at throttle body, intake manifold and PCV valve installation points EGR valve (stuck open). Fuel injector insulator. Engine compression. (See COMPRESSION INSPECTION .)

ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION/ENGINE COOLANT TEMPERATURE COMPENSATION INSPECTION

1. Connect the WDS or equivalent to the DLC-2.
2. Access the following PIDs: ECT IAT RPM
3. Verify that the engine is cold, then start the engine.
4. Verify that the engine speed decreases as the engine warms up. If the engine speed does not decrease or decreases slowly, inspect the following: ECT sensor and related wiring harness. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION .) Electronic throttle body and related wiring harness. (See THROTTLE BODY INSPECTION .)

LOAD COMPENSATION INSPECTION

1. Start the engine and idle it.
2. Connect the WDS or equivalent to the DLC-2.
3. Verify that P0506, P0507, or P0511 is not displayed. If P0506, P0507 or P0511 are displayed, perform DTC inspection. (See DTC TABLE .)
4. Access the RPM PID.
5. Verify that the engine speed is within the specification under each load condition. If load condition is not as specified, inspect the following: A/C switch and related wiring harness. (See CLIMATE CONTROL UNIT INSPECTION .) Fan switch and related wiring harness. (See CLIMATE CONTROL UNIT INSPECTION .)

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THROTTLE POSITION (TP) SWEEP INSPECTION

1. Connect the WDS or equivalent to the DLC-2.
2. Turn the ignition switch to the ON position.
3. Verify that none of the following DTC are displayed: P0122, P0123, P0222, P0223, P0638, P2100 *1 , P2101, P2102 *1 , P2103 *1 , P2106 *2 *2 , P2107, P2108, P2109 *2 , P2112 *2 , P2119, P2122, P2123, P2127, P2128, P2135, P2138 *1 Except California emission regulation applicable model. *2 California emission regulation applicable model. If any one DTC is displayed, perform DTC inspection.
4. Access TP_REL PID.
5. Verify that the PID reading is within the CTP value. (See PCM INSPECTION .) If the PID reading is out of range, perform the following: Remove the air duct from the throttle valve body. Verify that the throttle valve opens when the accelerator pedal is depressed. If the throttle valve opens, inspect the throttle position sensor and related wiring harness. If the throttle valve does not open, inspect the throttle actuator control motor and related wiring harness.
6. Gradually depress the throttle pedal and verify that the PID reading increases accordingly. If the PID reading drops momentarily, inspect the following: Throttle position sensor.
7. Fully depress the throttle pedal and verify that the PID reading is within WOT value. (See PCM INSPECTION .) If the PID reading is out of range, perform the followings: Remove the air duct from throttle valve body. Verify that the throttle valve opens when throttle pedal is depressed. If the throttle valve opens, inspect the throttle position sensor and related wiring harness. If the throttle valve does not open, inspect the throttle actuator control motor and related wiring harness.

FUEL CUT CONTROL SYSTEM INSPECTION

1. Warm up engine and idle it.
2. Turn off the electrical loads and A/C switch.
3. Connect the WDS or equivalent to the DLC-2.
4. Access RPM PID.
5. Listen for the fuel injector operation sound at all cylinders using the soundscope and monitor both PIDs while performing the following steps: Depress the accelerator pedal and increase the engine speed to 4,000 RPM . Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the fuel injector operation sound stops, and starts again when the engine speed drops below 2,200 RPM . If not as specified, inspect the following: ECT sensor and related wiring harness. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION .) Neutral/clutch pedal position switch and related wiring harness (MTX). (See CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION .) TR switch and related wiring harness (ATX). (See TRANSAXLE RANGE (TR) SWITCH INSPECTION .)

FUEL PUMP CONTROL SYSTEM INSPECTION

1. Crank the engine and verify that fuel pump relay operation sound is heard.
2. If operation sound is not heard, inspect the following: Fuel pump relay. (See RELAY INSPECTION .) Wiring harness and connectors (Main relay - fuel pump relay - PCM terminal 1AR (with immobilizer system), 1AQ (without immobilizer system).

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. (Scheme 523)

EGR CONTROL SYSTEM INSPECTION

1. Crank the engine and verify that EGR valve operation (initial operation) sound is heard. If the operation sound is not heard, connect the WDS or equivalent to the DLC-2 and verify that the DTC P0403 is shown. Perform DTC inspection. (See DTC TABLE .)
2. Start the engine and idle it.
3. Warm up the engine to normal operating temperature.
4. Access the following PIDs: ECT, RPM, SEGRP_DSD, APP1, APP2, VSS.
5. Idle the vehicle and verify that the SEGRP value is 0.
6. Put the vehicle in drive.
7. Depress the accelerator pedal and verify that the SEGRP_DSD value is increased. If the EGR valve increases, inspect the following: EGR valve (stuck open or close). Wiring harness and connectors (Main relay - EGR valve - PCM). If the SEGRP_DSD value does not increase, inspect the VSS, APP1, APP2, TP and ECT PIDs. (See PCM INSPECTION .)
8. Stop the vehicle and verify that the SEGRP value returns to 0.

PURGE CONTROL SYSTEM INSPECTION

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 2AN). Purge solenoid valve.
4. Warm up the engine to the normal operating temperature.
5. Stop the engine.
6. Connect the WDS or equivalent to the DLC-2 and verify that the DTC P0443 is shown. Perform DTC inspection. (See DTC TABLE .)
7. Turn the ignition switch to the ON position.
8. Access ECT PID.
9. Verify that the engine coolant temperature is more than 78 °C {173 °F} . If the WDS or equivalent indicates less than 78 °C {173 °F} , perform the ECT sensor inspection.
10. Set the vehicle on the dynamometer or chassis roller.
11. Drive vehicle at engine speed approx. 2000 RPM for 30 s or more .
12. Put a finger to the purge solenoid valve and verify that there is no vacuum applied while step 2 . If there is no vacuum, inspect the following: Wiring harness and connector (Main relay - purge solenoid valve - PCM terminal 2AN). Purge solenoid valve. MAF, APP1, APP2, TP and LOAD PIDs. If there is vacuum, inspect the following: Vacuum hose (Purge solenoid valve - charcoal canister).

A/C CUT-OFF CONTROL SYSTEM INSPECTION

1. Start the engine.
2. Turn the A/C switch and the fan switch on.
3. Verify that the A/C compressor magnetic clutch actuates. If it does not actuate, go to symptom troubleshooting «No. 23 A/C DOES NOT WORK SUFFICIENTLY»(ref-177559-S25652661202005060200000) .
4. Fully open the throttle valve and verify that the A/C compressor magnetic clutch does not actuate for 2-5 s . If it actuates, inspect as follows: A/C relay. Open or short to GND circuit in wiring harness and connectors (Ignition switch-A/C relay-PCM terminal 1AN). A/C related parts. APP1, APP2 PIDs.

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1. Verify that the battery voltage is more than 12.4 V. If the battery voltage is less than 12.4 V, charge the battery or connect the external power supply.
2. Connect the WDS or equivalent and access ECT PID.
3. Turn A/C switch to off.
4. Verify ECT PID is less than 98 °C {209 °F}. If ECT PID more than 98 °C {209 °F}, inspect ECT sensor and related wiring harnesses.
5. Verify that the cooling fan does not operate with ECT PID is less than 98 °C {209 °F} while the ignition switch is ON. If the cooling fan operates, inspect for following parts and related wiring harnesses: ECT sensor. A/C switch. A/C refrigerant pressure switch (High/low pressure). A/C refrigerant pressure switch (Medium pressure). VSS. A/C magnetic clutch. Fan control signal circuit (between fan control module terminal B and PCM terminal 1W). If the all items are normal, replace fan control module.
6. Verify the cooling fan operates while the A/C switch to ON with the ignition switch at ON position. If the cooling fan does not operate, inspect for following: A/C switch. A/C refrigerant pressure switch (high/low pressure). Fan control module power supply circuit. Fan control module GND circuit. Fan control signal circuit (between fan control module terminal B and PCM terminal 1W). If the all items are normal, replace fan control module.
7. Verify that the cooling fan operates as specified. (Scheme 524) If the cooling fan operation is not specified, inspect for following: A/C refrigerant pressure switch (Medium pressure). If the A/C refrigerant pressure switch (Middle pressure) is normal, replace fan control module.
8. Turn A/C switch to off.
9. Start the engine and idle it.
10. Verify that the cooling fan operating speed increases relative to ECT PID increases. If the cooling fan speed does not increase inspect following: ECT sensor (characteristic). (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION.) Fan control signal circuit (between fan control module terminal B and PCM terminal 1W). If the all items are normal, replace fan control module.

Evaporative System Test Outline

1. To verify that the problem has been fixed properly after repairs, the run Drive Cycle or evaporative system test must be performed.

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1. Perform the following SST (Evaporative Emission System Tester 134-01049) self-test: Verify that the gas cylinder valve is closed and the control valve located on the tester is in the TEST position. All tester displays should be off at this time. Connect the long hose (part of SST ) to the tester. Connect the manifold assembly (part of SST ) to the long hose as shown. Open the gas cylinder valve and verify the gas cylinder regulator left gauge reads 10 to 12 psi (preset at factory). If not, refer to the tester operators manual to contact tester manufacturer. Press the ON/OFF switch to turn on the SST and make sure the left display reads 0.0 . Turn the control valve on the tester to the FILL position. Verify the left display reading is within 13.9 to 14.0 in of water. If not, adjust the pressure using the regulator knob located on the right side of the tester. Turn the control valve to TEST position and press the START switch. After the 2 min countdown (left display) is completed, the right display shows the total pressure loss for that period. A 0.5 in of water loss is acceptable on the self-test. If the loss is 0.5 in or more of water, do one or more self-tests. If the test repeatedly fails, check for leaks using the ultrasonic leak detector (part of SST ).
2. Press the RESET switch to set the left display reading to 0.0 .
3. Connect the fuel cap test adapter (part of SST) to the manifold assembly and fuel-filler cap from the vehicle. If the fuel-filler cap is not a genuine part, replace it.
4. Connect the threaded test adapter (part of SST) to the manifold assembly and fuel-filler neck.
5. Connect the WDS or equivalent to the DLC-2.
6. Turn the ignition switch to the ON position (Engine off).
7. Request the PCM for on-board device control (Mode 08) using the WDS or equivalent to close the Change-Over Valve (COV) in EVAP system leak detection pump. NOTE: The COV is closed for 10 min unless the following any actions are done: The engine is started. The ignition switch is turned to off position.
8. Turn the control valve to the FILL position.
9. Wait (maximum 40 s) until the left display reads 13.5 to 14 in of water. If the reading is slightly below, adjust it using the regulator knob. If the reading is far below, the EVAP system has a large leak. Check for leaks (using the ultrasonic leak detector if necessary) and repair.
10. Turn the control valve to the TEST position and press the START switch.
11. After the 2 min countdown (left display) is completed, check the test result (the failed/passed light on the tester). If the Green light illuminates, the EVAP system is OK. If the Red light illuminates, the EVAP system has leakage. Check for leaks using the ultrasonic leak detector and repair.
12. Close the gas cylinder valve.
13. Turn the control valve to the FILL position.
14. Press the ON/off switch to turn off the tester.