Diagnostic procedure
WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
| STEP | INSPECTION | RESULTS | ACTION |
|---|---|---|---|
| 1 | Inspect for the following
Are all items normal? |
Yes | Go to the next step. |
| No | Service if necessary Repeat Step 1 | ||
| 2 | Connect the M-MDS to the DLC-2. Switch the ignition to ON (Engine off) Retrieve any DTCs. Are there any DTCs displayed? |
Yes | DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] .) |
| No | No DTC is displayed: Go to the next step |
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| 3 | Is engine overheating? | Yes | Go to symptom troubleshooting "No. 17 Cooling system concerns-overheating" (See NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI-3.7] .) |
| No | Go to the next step. | ||
| 4 | Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders Are wiring harness conditions normal? |
Yes | Go to the next step |
| No | Repair the wiring harnesses | ||
| 5 | Inspect the spark plug conditions Is spark plug wet, covered with carbon or grayish white? |
Yes | Spark plug is wet or covered with carbon: Inspect for fuel leakage from fuel injector Spark plug is grayish white: Inspect the fuel injector for clogging |
| No | Install the spark plugs on original cylinders. Go to the next step |
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| 6 | Visually inspect the CKP sensor and teeth of crankshaft pulley Are the CKP sensor and teeth of crankshaft pulley normal? |
Yes | Go to the next step |
| No | Replace the malfunctioning part. | ||
| 7 | Attempt to start engine at part throttle. Does engine run smoothly at part throttle? |
Yes | Inspect the electronic throttle control system operation (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) |
| No | Go to the next step | ||
| 8 | Install the fuel pressure gauge between the fuel pipe and fuel distributor Measure the fuel line pressure. Is fuel line pressure correct? (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] .) |
Yes | Go to the next step |
| No | Zero or low: Inspect the fuel pump relay and the fuel pump circuit Inspect the fuel line for clogging If there is no malfunction, replace the fuel pump unit (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] .) High: Replace the fuel pump unit (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] .) |
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| 9 | Is the fuel line pressure held after ignition is turned off? (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] .) |
Yes | Go to the next step |
| No | Inspect the fuel injector (See FUEL INJECTOR INSPECTION [MZI-3.7] .) If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] .) |
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| 10 | Disconnect a vacuum hose from purge solenoid valve and plug opening end of vacuum hose. Start engine Is starting condition improved? |
Yes | Inspect if the purge solenoid valve is stuck open |
| No | Go to the next step | ||
| 11 | Inspect the MAF sensor for following
Is there any malfunction? |
Yes | Repair or replace the malfunctioning part. |
| No | Go to the next step. | ||
| 12 | Visually inspect the exhaust system part Is there any deformed exhaust system part? |
Yes | Replace the suspected part |
| No | Go to the next step. | ||
| 13 | Inspect the starting system (See STARTER INSPECTION [MZI-3.7] .) Is starting system normal? |
Yes | Inspect for loose connectors or poor terminal contact If connectors are normal, inspect the PCV valve. |
| No | Repair or replace components as required. | ||
| 14 |
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