Component Tests and General Diagnostics
ENGINE CONTROL SYSTEM OPERATION INSPECTION [AJ]Input Signal System Investigation Procedure
1. Find an unusual signal.
2. Locate its source.
3. Repair or replace the defective part.
4. Confirm that the unusual signal has been erased.
Finding unusual signals
While referring to ON-BOARD DIAGNOSTIC TEST [AJ], use the PID/DATA monitor and record function to inspect the input signal system relating to the problem.
1. Start the engine and idle the vehicle. You can assume that any signals that are out of specifications by a wide margin are unusual.
2. When recreating the problem, any sudden change in monitor input signals that is not consciously created by the driver can be judged as unusual.
Locating the source of unusual signals
CAUTION:
- Compare the WDS or equivalent monitor voltage with the measurement voltage using the digital measurement system function. If you use another tester, misreading may occur.
- When measuring voltage, attach the tester GND to the GND of the PCM that is being tested, or to the engine itself. If this Is not done, the measured voltage and actual voltage may differ.
- After connecting the pin to a waterproof coupler, confirming continuity and measuring the voltage, inspect the waterproof connector for cracks. If there are any, use sealant to fix them. Failure to do this may result in deterioration of the harness or terminal from water damage, leading to problems with the vehicle.
Variable resistance type 1 (TP sensor and EGR boost sensor)
Investigate the input signal system for variable resistance type 1
1. When you get an unusual signal, 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 WDS or equivalent voltages, inspect: the harness for open or short circuit circuits.
- If the sensor and WDS or equivalent voltages are the same, inspect for the following points concerning the sensor connector.
- If there are no problems, proceed to next investigation below.
- Female terminal opening is loose.
- Coupler (pin holder) damage.
- Pin discoloration (blackness).
Investigate the standard power supply system for variable resistance type 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 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 harness.
- Harness/pin crimp is loose or disconnected.
Investigate the GND system for variable resistance type 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 harness
- Female terminal opening is loose open or short circuit in harness.
- Coupler (pin holder) damage.
- Pin discoloration (blackness).
- Harness/pin crimp is loose or disconnected.
Variable resistance type 2 (fuel tank level sensor and mass air flow (MAF) sensor).
Investigate the GND system for variable resistance type 2.
- 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 harness.
- Female terminal opening is loose.
- Coupler (pin holder) damage.
- Pin discoloration (blackness).
- Harness/pin crimp is loose or disconnected.
Investigate the input signal system for variable resistance type 2
1. When you get an unusual signal, 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 WDS or equivalent voltages, inspect the harness for open or short circuit circuits.
- If the sensor and 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.
Investigate the electrical supply system for variable resistance type 2
- 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 harness.
- Harness/pin crimp is loose or disconnected.
Thermistor type (IAT sensor and ECT sensor).
Investigate the input signal system for thermistor type
1. When you get an unusual signal, measure the #1 PCM terminal voltage.
- If the #1 terminal voltage and the WDS or equivalent monitor voltages 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 WDS or equivalent voltages, inspect the harness for open or short circuit circuits.
- If the sensor and 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.
Investigate the GND system for thermistor type
- 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 harness.
- Female terminal opening is loose.
- Coupler (pin holder) damage.
- Pin discoloration (blackness).
- Harness/pin crimp is loose or disconnected.
VSS
1. Measure the #1 PCM terminal voltage and confirm that it is at 0 V or 5 V when the ignition key at ON and the engine at idle.
- If it is at 0 V or 5 V, intermittent concern exists. (See INTERMITTENT CONCERN TROUBLESHOOTING [AJ].) Intermittent Concern Troubleshooting
- If not, inspect the following points concerning the PCM connector.
- If there is no problem, inspect for the following.
- 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 and confirm that it is at 0 V or 5 V when the ignition key at ON and the engine at idle.
- If it is at 0 V or 5 V, intermittent concern exists. (See INTERMITTENT CONCERN TROUBLESHOOTING [AJ].) Intermittent Concern Troubleshooting
- If not, inspect the following points concerning the sensor connector.
- If there is no problem, inspect for the following.
- Female terminal opening is loose.
- Coupler (pin holder) damage.
- Pin discoloration (blackness).
- Harness/pin crimp is loose or disconnected.
3. Confirm that the #3 terminal switch voltage is at 0 V.
- If it is at 0 V, inspect the sensor. If necessary, replace the sensor.
- If necessary, replace the sensor.
- If not, inspect for the following.
- Open circuit in 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. Measure the manifold vacuum using a vacuum gauge.
- If not as specified, inspect following.
- Air suction at throttle body, intake manifold and PCV valve installation points.
- Accelerator cable free play.
- Fuel injector insulator.
- Engine compression.
Specification: More than 60 kPa {450 mmHg, 18 inHg}
Idle Air Control Inspection
Engine coolant temperature compensation inspection
1. Connect the SSTs (WDS or equivalent) to DLC-2.
2. Select the PID/DATA MONITOR AND RECORD function on the WDS or equivalent display.
3. Select the following PIDs.
- ECT
- RPM
4. Verify that the engine is in cold condition, then start the engine.
5. 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 harness.
- IAC valve and related harness.
Intake Manifold Communication Control (IMCC) System Inspection
1. Connect WDS or equivalent to DLC-2.
2. Verify that no DTC detected.
- If any DTC is detected perform appropriate DTC inspection. (See ON-BOARD DIAGNOSTIC TEST [AJ].)
3. Access the IMCC PID.
4. Remove the IMCC actuator with connector connected.
5. Turn the ignition switch to ON.
6. Verify that the IMCC actuator moves when the IMCC PID from OFF to ON using the simulation function.
- If the IMCC actuator does not move, inspect and repair or replace followings:
- IMCC actuator.
- Harness and connectors between PCM and IMCC actuator.
Fuel Injector Operation Inspection:
Fuel Injector Operation Inspection
Ignition Timing Control Inspection
1. Start the engine and run it at idle.
2. Warm up the engine to normal operating temperature.
3. Connect the SSTs (WDS or equivalent) to the DLC-2.
4. Select the PID/DATA MONITOR AND RECORD function on the WDS or equivalent display.
5. Select the SPARKED PID.
6. Verify that SPARKED PID is within the specification.
Specification: BTDC 4 degrees delta 16 degrees (100 degrees ± 6 degrees)
7. Increase the engine speed and verify that the SPARKED PID value is advanced.
- If it is not advanced, inspect the following.
- CKP sensor and related harness.
- MAF sensor and related harness.
Fuel Cut Control System Inspection
1. Warm-up engine and let it idle.
2. Turn off the electrical loads and A/C switch.
3. Connect the WDS or equivalent to the DLC-2.
4. Select RPM PID.
5. Listen for the fuel injector operation sound at all cylinders using the sound scope and monitor PID 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 fuel injector operation sound stops when the accelerator pedal is released and starts again when the engine speed drops below 1,200 rpm.
- If not as specified, inspect the following:
- ECT sensor and related harness.
- TR switch and related harness.
Fuel Pump Operation Inspection
CAUTION: Connecting the wrong check connector terminal may possibly cause malfunction. Carefully connect the specified terminal only.
1. Short the check connector terminal F/P to body GND using a jumper wire. (See AFTER REPAIR PROCEDURE [AJ].) After Repair Procedure
2. Remove the fuel-filler cap.
3. Turn ignition switch to ON position.
4. Verify that the fuel pump operation sound is heard.
- If no operation sound is heard, proceed to next step.
5. Measure the voltage at harness side fuel pump connector terminal B.
Specification: B+ (Ignition switch at ON)
- If the voltage is as specified, inspect the following:
- Fuel pump continuity
- Fuel pump GND
- Wiring harness between fuel pump relay and PCM terminal 95
- If not as specified, inspect the following:
- Fuel pump relay
- Wiring harness connector (Main relay-fuel pump relay-fuel pump).
Fuel Pump Control System Inspection
1. Crank the engine and verify that fuel pump relay operation sound is heard.
- If operation sound is not heard, inspect the following:
- Fuel pump relay
- Wiring harness and connectors (Main relay-fuel pump relay-PCM terminal 95)
EGR Control System Inspection
1. Verify that EGR valve operation (initial operation) sound is heard when the ignition switch is turned to ON position.
- If the operation sound is not heard, connect WDS or equivalent to the DLC-2 and verify that the DTC P0403 is shown. Perform DTC inspection. (See DTC TABLE [AJ].) Diagnostic Trouble Code Descriptions
2. Start the engine and run it at idle.
3. Warm-up the engine to normal operating temperature.
4. Select the following PIDs:
- ECT
- RPM
- SEGRP
- TP
- 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 increases.
- If the SEGRP value does not increase, inspect the VSS, TP and ECT PIDs. (See PCM INSPECTION [AJ].)
- If the SEGRP value does increases, inspect the following:
- EGR valve (Stuck open or close)
- Wiring harness and connectors (Main relay-EGR valve-PCM)
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 85)
- 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 displayed. Perform DTC inspection. (See DTC TABLE [AJ].) Diagnostic Trouble Code Descriptions
7. Turn ignition switch to ON position.
8. Select ECT PID.
9. Verify that the engine coolant temperature is 60 degrees C {140 degrees F} or above.
- If WDS or equivalent indicates less than 60 degrees C {140 degrees F}, perform the ECT sensor inspection.
10. Set the vehicle on the dynamometer or chassis roller.
WARNING: When the dynamometer or chassis roller is operating, there is a possibility that the operator may come into contact with or be caught up in the rotating parts, leading to serious injuries or death. When performing work while the dynamometer or chassis roller is operating, be careful not to come into contact with or be caught up in any of the rotating parts.
11. Drive vehicle with engine speed at approx. 2,000 rpm for more than 30 s.
12. Put a finger to the purge solenoid valve and verify that there is no vacuum applied.
- If there is no vacuum, inspect the following:
- Wiring harness and connector (Main relay- purge solenoid valve-PCM terminal 85)
- Purge solenoid valve
- MAF, 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 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". No.23 A/C Does Not Work Sufficiently
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 the following:
- A/C relay
- Open or short to GND circuit in wiring harness and connectors (Ignition switch- A/C relay-PCM terminal 47)
- A/C related parts
- TP PID
Spark Test
Step 1-Step 6:
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.
Evaporative Emission (EVAP) System Leak Inspection
- To verify that the problem has been fixed properly after repairs, the run drive cycle or EVAP system leak inspection must be performed.
EVAP system leak inspection using WDS or equivalent
NOTE:
EVAP system test outline
- The EVAP system test, which can substituted for the run drive cycle as an EVAP control system repair confirmation method, can be done while operating the WDS in the KOEO (Key On Engine Off) condition instead of actually driving the vehicle.
EVAP system test description
- The EVAP system test finds gas leaks in the system using the PCM to monitor changes in the air pump load current of the EVAP system leak detection pump. This test starts after sending an on-demand test signal from the WDS to the PCM. The PCM controls the air pump and change-over-valve operation and also stores the load current of the air pump as follows:
i. The PCM commands turn the air pump on and retrieve the air pump load current value (LDP_MON PID) as a reference current (LDP_REF PID).
ii. After retrieving a reference current value, the PCM commands the change-over-valve to open, then captures the air pump load current value (LDP_MON PID) as idle current (LDP_IDL PID). The EVAP system will be pressurized from this phase.
iii. The PCM continues to monitor the air pump load current value (LDP_MON PID) until the end of the test.
- You can confirm whether any evaporative gas leak occurred or not by reading the test result.
EVAP system malfunction judgment
- The WDS calculates the stored air pump load current value and displays the results as follows:
- Small leak results (DTC P0442) = LDP_SLDV.
- Very small leak results (mA/S: DTC P0456) = LDP_VSLDV.
- Very small leak results (mA: DTC P0456) = LDP_REF-LDP_MON (when test ended).
- IMO result (air pump operation) = LDP_MON (when test ended).
- COV result (change-over-valve statues) = LDP_REF -LDPJDL.
Evaporative system test procedure
1. Select the EVAP system test from the Toolbox on the WDS display and follow the instructions.
2. Verify that all of the following PIDs are within the specifications at the pre-test confirmation screen.
NOTE:
- To successfully perform this procedure, all PIDs must be within the following specifications before proceeding to the next step.
- Record the VPWR value.
- The PCM will cancel the EVAP system test if the VPWR PID value falls lower than 11.0 V during the test.
3. Start the engine.
4. Drive the vehicle or let the engine idle more than 20 min.
5. Turn ignition switch off, then turn it to the ON position again (Key On Engine Off).
6. Press the tick icon to start the test.
7. Verify that each test result is indicated with green.
- If any test result is indicated with red, diagnose the problem using the following DTC troubleshooting procedure or component inspection procedure.
EVAP system leak inspection using leak tester
1. Perform the following SST (EVAP System Tester 134-01049) self-test:
NOTE: If the tester does not work correctly during the self-test, refer to the tester operators manual for a more detailed self-test procedure.
1. Verify that the control valve on the panel is in the HOLD position then open the nitrogen bottle valve.
2. Connect the vehicle interface hose (part of the SST) to the SELF-TEST port located on the control panel. Hand tighten the fitting. (Do not overtighten.)
3. Turn the control valve to the TEST position.
4. The gauge should read 331-381 mm {13- 15 in} of water.
- If the gauge is not reading in this range, adjust the pressure by turning the black knob on the low pressure regulator at the nitrogen bottle.
5. Turn the control valve to the HOLD position.
6. Verify that the gauge holds pressure and that the flow meter reads no flow.
- If there is no drop in pressure and no flow, the tester passes the self-test.
- If the gauge leaks down, refer to the tester operators manual.
2. Connect the SST to the vehicle.
1. Verify that the control valve on the panel is in the HOLD position then open the nitrogen bottle valve.
2. Remove the fuel-filler cap from the vehicle.
- If the fuel-filler cap is not a MAZDA part or equivalent, replace it.
3. Connect the receiver assembly (SST: 134-01051) to the vehicle cap test hose assembly (part of the SST) and the fuel-filler cap from the vehicle.
4. Connect the cap adaptor (SST: 134-01050) to TEST HOSE the vehicle cap test hose assembly (part of ASSEMBLY the SST) and to the fuel-filler neck.
5. Connect the vehicle interface hose (part of the SST) to the center fitting of the vehicle cap HOSE test hose assembly (part of the SST).
3. Connect the WDS or equivalent to the DLC-2.
4. Turn the ignition switch to the ON position (Engine off).
5. Request the PCM on-board device control (Mode ASSEMBLY 08) using the WDS or equivalent to close the change-over valve (COV) in the 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 off position.
6. Make sure the control valve on the 134-01049 is in the HOLD position and that the valve on the cylinder of nitrogen gas is open.
7. Turn the control valve to the open position and let the system fill. You should note a drop in the gauge pressure along with the flow meter being pegged at maximum flow for several minutes depending on how full or empty the fuel tank is, and how long it takes to completely fill and pressurize the evaporative emissions system hoses.
8. If the gauge and the flow meter do not settle to a measurable level after 2-3 min, then verify that the cut or vent valve is properly closed.
9. Verify the pressure gauge and flow meter reading to determine if there is an evaporative emissions leak:
NO EVAPORATIVE LEAK:
- The flow meter registers "zero flow" and the pressure gauge returns to the pre-set pressure of 356 mm {14 in} of water (H2O).
EVAPORATIVE LEAK:
- The pressure does not return to the preset level of 356 mm {14 in} of water (H2O) when measuring the flow. See "SETTING LEAK STANDARD FOR TESTING" (.020 to.040 inch H2O) of the Evaporative Emissions Tester operators manual (134-01067).
NOTE: Turn the control valve to the HOLD position then disconnect the SST.