Emission System: Diagnosis Mazda MX-5 NC

EVAPORATIVE EMISSION (EVAP) SYSTEM LEAK DETECTION PUMP INSPECTION [LF]

Note. Perform the following procedure only when directed.

Scheme 9

1. Remove the battery cover.
2. Disconnect the negative battery cable. (See «BATTERY REMOVAL/INSTALLATION [LF]»(ref-244448-S25513985422006092400000) .)
3. Remove the EVAP system leak detection pump. (See «EVAPORATIVE EMISSION (EVAP) SYSTEM LEAK DETECTION PUMP REMOVAL/INSTALLATION [LF]»(ref-244459-S09199722012006092400000) .).
4. Blow air into port A and verify that there is airflow from port B. If not as specified, replace the EVAP system leak detection pump. (See «EVAPORATIVE EMISSION (EVAP) SYSTEM LEAK DETECTION PUMP REMOVAL/INSTALLATION [LF]»(ref-244459-S09199722012006092400000) ).
5. Blow air into port B and verify that there is airflow from port A. If not as specified, replace the EVAP system leak detection pump. (See «EVAPORATIVE EMISSION (EVAP) SYSTEM LEAK DETECTION PUMP REMOVAL/INSTALLATION [LF]»(ref-244459-S09199722012006092400000) ). If as specified, perform the following " «RESISTANCE INSPECTION»(ref-244459-S28778115352006092400000) ".

Resistance Inspection

1. Inspect resistance of the EVAP system leak detection pump. If not as specified, replace the EVAP system leak detection pump. (See «EVAPORATIVE EMISSION (EVAP) SYSTEM LEAK DETECTION PUMP REMOVAL/INSTALLATION [LF]»(ref-244459-S09199722012006092400000) ). If as specified, carry out the «CIRCUIT OPEN/SHORT INSPECTION»(ref-244459-S40002275012006092400000) .

EVAP SYSTEM LEAK DETECTION PUMP TERMINALS RESISTANCE SPECIFICATIONS

Scheme 10

Circuit Open/Short Inspection

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [LF]»(ref-244452-S11022070362006092400000) .)
2. Inspect the following wiring harness for open or short circuit (continuity check).

PURGE SOLENOID VALVE INSPECTION [LF]

Note. Perform the following procedure only when directed.

Scheme 11

1. Remove the purge solenoid valve without disconnecting the evaporative hose. (See «PURGE SOLENOID VALVE REMOVAL/INSTALLATION [LF]»(ref-244459-S15366069222006092400000) ).
2. Verify that the airflow is as indicated in «PURGE SOLENOID VALVE AIRFLOW REFERENCE TABLE»(ref-244459-S42863110412006092400000) . If as specified in «PURGE SOLENOID VALVE AIRFLOW REFERENCE TABLE»(ref-244459-S42863110412006092400000) , perform the «CIRCUIT OPEN/SHORT INSPECTION»(ref-244459-S01587873202006092400000) . If not as specified in «PURGE SOLENOID VALVE AIRFLOW REFERENCE TABLE»(ref-244459-S42863110412006092400000) , inspect the purge solenoid valve. (See «PURGE SOLENOID VALVE REMOVAL/INSTALLATION [LF]»(ref-244459-S15366069222006092400000) .) PURGE SOLENOID VALVE AIRFLOW REFERENCE TABLE Measured condition Continuity between A-B When voltage is not applied between terminals A and B No airflow When voltage is applied between terminals A and B Airflow detected

Scheme 12

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [LF]»(ref-244452-S11022070362006092400000) .)
2. Inspect the following wiring harnesses for open or short circuit (continuity check).

ROLLOVER VALVE INSPECTION [LF]

Note. The rollover valve cannot be removed and inspected as it is built into the fuel tank.

1. Perform the fuel tank inspection. (See «FUEL TANK INSPECTION [LF]»(ref-244458-S38161467562006092400000) .)

FUEL SHUT-OFF VALVE INSPECTION [LF]

Note. The fuel shut-off valve cannot be removed and inspected as it is built into the fuel tank.

1. Perform the fuel tank inspection. (See «FUEL TANK INSPECTION [LF]»(ref-244458-S38161467562006092400000) .)

Scheme 13

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Scheme 18

1. Remove the plug hole plate. (See «PLUG HOLE PLATE REMOVAL/INSTALLATION [LF]»(ref-244453-S34821156912006092400000) .)
2. Remove the battery cover.
3. Disconnect the negative battery cable. (See «BATTERY REMOVAL/INSTALLATION [LF]»(ref-244448-S25513985422006092400000) .)
4. Drain the engine coolant from the radiator. (See «ENGINE COOLANT REPLACEMENT [LF]»(ref-244456-S02885124352006092400000) .)
5. Remove the service hole cover. Remove the suspension tower bar (joint), (right side) and (left side). (See «FRONT SUSPENSION TOWER BAR REMOVAL/INSTALLATION»(ref-244475-S20579544822006092400000) .) Remove the wiper arm: (See «WIPER ARM AND BLADE REMOVAL/INSTALLATION»(ref-244477-S04548950182006092400000) .) Remove the cowl grille. (See «COWL GRILLE REMOVAL/INSTALLATION»(ref-244478-S13431226702006092400000) .) Remove the side cowl grille. (See «SIDE COWL GRILLE REMOVAL/INSTALLATION»(ref-244478-S39487642132006092400000) .) Move the cooler pipe No.3 and heater pipe slightly out of the way. Remove the service hole cover.
6. Remove the harness bracket.
7. Disconnect the heater hose and move the heater pipe slightly out of the way.
8. Disconnect the EGR valve connector.
9. Set the SST to the EGR valve installation bolt.
10. Remove both EGR valve installation bolts.
11. Remove the EGR valve with the engine coolant hose.
12. Disconnect the engine coolant hose from the EGR valve.
13. Replace the EGR valve gasket.
14. Install in the reverse order of removal.

EGR VALVE INSPECTION [LF]

Note. Perform the following procedure only when directed.

On-Vehicle Inspection

1. Verify that the buzzing sound (valve operation sound) is heard from the EGR valve when engine cranking. If the buzzing sound is not heard, perform the resistance inspection.

Scheme 19

1. Remove the plug hole plate. (See «PLUG HOLE PLATE REMOVAL/INSTALLATION [LF]»(ref-244453-S34821156912006092400000) .)
2. Disconnect the battery cover.
3. Disconnect the negative battery cable. (See «BATTERY REMOVAL/INSTALLATION [LF]»(ref-244448-S25513985422006092400000) .)
4. Disconnect the EGR valve connector. (See «EGR VALVE REMOVAL/INSTALLATION [LF]»(ref-244459-S41291996702006092400000) ).
5. Measure the resistance between the EGR valve terminals. If within the specification, perform out the «CIRCUIT OPEN/SHORT INSPECTION»(ref-244459-S33466035612006092400000) . If not within the specification, replace the EGR valve. (See «EGR VALVE REMOVAL/INSTALLATION [LF]»(ref-244459-S41291996702006092400000) ). STANDARD RESISTANCE SPECIFICATIONS Terminal Resistance (ohm) C-E C-A D-B D-F 12-16

1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [LF]»(ref-244452-S11022070362006092400000) .)
2. Inspect the following wiring harnesses for open or short circuit (continuity check).

WARM-UP THREE-WAY CATALYTIC CONVERTER (WU-TWC) INSPECTION [LF]

Note. Make sure that no HO2S DTCs have been detected. If detected, this inspection is not applicable for WU-TWC inspection.

1. Connect the WDS or equivalent and monitor PIDs as following. Monitor the WU-TWC using O2S11 PID for upstream HO2S and O2S12 PID for downstream HO2S.
2. Monitor the appropriate PIDs.
3. Drive the vehicle for 10 min at 65-96 km/h {40-60 mph} to allow the front catalytic converter to reach operating temperature.
4. Stop the vehicle and leave it in a safe place.
5. Idle the engine.
6. Record PIDs for 1 min.
7. Select the appropriate PIDs and read the graph.
8. Count the number of times (inversions) that the upstream HO2S graph line actually crosses the 0.5 V line.
9. Count the number of times (inversions) that the downstream HO2S graph line actually crosses the 0.5 V line. NOTE: Do not count the number of peaks. (Scheme 21)
10. Using the following equation, calculate the value of ratio. Equation RATIO = Upstream HO2S inversion divided by downstream HO2S inversion If the ratio is 1.5 or more or there is no downstream HO2S inversion, the WU-TWC is functioning properly. If the ratio is less than 1.5, the WU-TWC is not functioning properly. Replace the WU-TWC.

Scheme 20

Equation

RATIO = 30 inversions (upstream HO2S inversions) divided by 5 inversions (downstream HO2S inversions) = 6.0 (good WU-TWC)

Scheme 21

Scheme 22

Scheme 23

Equation

RATIO = 30 inversions (upstream HO2S inversions) divided by 27 inversions (downstream HO2S inversions) = 1.1 (bad WU-TWC)