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HOMESERVICE MANUALSMAZDA1999626 ES, 2.5 D, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 432 (ON-BOARD DIAGNOSTIC (ENGINE CONTROL SYSTEM 13BMSP])DTC P0456DIAGNOSTIC PROCEDURE

1999 Mazda 626 ES, 2.5 D, Standard

Diagnostic procedure

1999 Mazda 626 ES, 2.5 D, StandardSECTION Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0456 DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED Have FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS (EVAP system related) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Bulletins and/or on-line repair information availability. Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY RELATED PENDING CODE OR STORED DTC Turn the ignition switch off, then to the ON position (Engine off). Verify the related PENDING CODE or stored DTCs. Are other DTCs present?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE .)
3		No	Go to the next step.
4	CLASSIFY INTERMITTENT CONCERN OR CONTINUOUS CONCERN Perform the "Evaporative System Leak Inspection". (See EVAPORATIVE EMISSION (EVAP) SYSTEM LEAK INSPECTION .) Does the test produce a failure?	Yes	Go to the next step.
4		No	Intermittent concern exists. Perform the "INTERMITTENT CONCERNS TROUBLESHOOTING". (See INTERMITTENT CONCERN TROUBLESHOOTING .)
5	LOCATE LEAK POINT Inspect the following for leakage using the Evaporative emission tester: (See EVAPORATIVE EMISSION (EVAP) SYSTEM LEAK INSPECTION .) Charcoal canister Catch tank Fuel-filler cap EVAP hoses and pipes Fuel tank Is leakage found?	Yes	Repair or replace the malfunctioning part, then go to Step 10.
5		No	Go to the next step.
6	INSPECT PURGE SOLENOID VALVE Inspect the purge solenoid valve. (See PURGE SOLENOID VALVE INSPECTION .) Is there any malfunction?	Yes	Replace the purge solenoid valve, then go to Step 10. (See INTAKE-AIR SYSTEM HOSE ROUTING DIAGRAM .)
6		No	Go to the next step.
7	INSPECT EVAPORATIVE SYSTEM OPERATION Connect all disconnected connectors and hoses. Place the clamp on the hose between the EVAP system leak detection pump and air filter. Perform the "Evaporative System Leak Inspection". (See EVAPORATIVE EMISSION (EVAP) SYSTEM LEAK INSPECTION .) Does the test produce a failure?	Yes	Go to Step 9.
7		No	Go to the next step.
8	INSPECT FOR EVAP SYSTEM LEAK DETECTION PUMP LEAKAGE Remove the clamp. Perform the "Evaporative System Leak Inspection". (See EVAPORATIVE EMISSION (EVAP) SYSTEM LEAK INSPECTION .) Does the test produce a failure?	Yes	Replace the EVAP system leak detection pump, then go to Step 10. (See EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM REMOVAL/INSTALLATION .)
8		No	Go to the next step.
9	INSPECT INSTALLATION OF FUEL PUMP UNIT Inspect the fuel pump unit for damage, insufficient, or poor sealing. Is it normal?	Yes	Go to the next step.
9		No	Repair or replace the malfunctioning part, then go to the next step.
10	VERIFY TROUBLESHOOTING OF DTC P0456 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the WDS or equivalent. Perform the evaporative test leak inspection. (See EVAPORATIVE EMISSION (EVAP) SYSTEM LEAK INSPECTION .) Does the test produce a failure?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION .)
10		No	Go to the next step.
11	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
11		No	DTC troubleshooting completed.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.