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 | Verify 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 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". |
| No | Go to the next step | ||
| 4 | Connect the M-MDS to the DLC-2. Access APP1, APP2, RPM, VPWR, MAF, TP1, TP2 and VSS PIDs Drive the vehicle with monitoring PIDs. Are PIDs within specifications? (See PCM INSPECTION [MZI-3.7] .) |
Yes | Go to the next step. |
| No | APP1, APP2 PIDs: Inspect if output signal from APP sensor changes smoothly RPM PID: Inspect the CKP sensor and related wiring harness for vibration or intermittent open/short circuit VPWR PID: Inspect for open circuit intermittently. MAF PID: Inspect for open circuit of the MAF sensor and related wiring harness intermittently. TP1, TP2 PID: Inspect if output signal from TP sensor changes smoothly VSS PID: Inspect for open circuit of VSS and related wiring harness intermittently. |
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| 5 | Visually inspect the CKP sensor and teeth of crankshaft pulley Are CKP sensor and teeth of crankshaft pulley normal? |
Yes | Go to the next step. |
| No | Replace the malfunctioning part. | ||
| 6 | 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. | ||
| 7 | Perform the electronic throttle control system operation inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does the electronic throttle control system function properly? |
Yes | Go to the next step. |
| No | Repair or replace the malfunctioning part according to electronic throttle system operation inspection results | ||
| 8 | Visually inspect deformed exhaust system part Is there any deformed exhaust system part? |
Yes | Replace the suspected part |
| No | Go to the next step | ||
| 9 | Install 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: Perform "Fuel Pump Operation Inspection" and "Fuel Pump Control System Operation Inspection", repair or replace according to inspection results 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: Perform "Fuel Pump Control System Operation Inspection", repair or replace according to inspection results If there is no malfunction, replace the fuel pump unit (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] .) |
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| 10 | Visually inspect for fuel leakage at fuel injector O-ring and fuel line Service if necessary Is 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 If the fuel injector is normal, replace the fuel pump unit (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] .) |
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| 11 | Perform the Fuel Pump Speed Control Inspection (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does the fuel pump speed control work properly? |
Yes | Go to the next step |
| No | Inspect and replace for malfunctioning part, according to inspection results | ||
| 12 |
NOTE:
Connect a pressure gauge to A/C low and high pressure side linesTurn the A/C on and measure low side and high side pressureAre pressures within specifications?(See
REFRIGERANT PRESSURE CHECK
)
|
Yes | Go to the next step |
| No | If the A/C is always on, go to symptom troubleshooting "No 24 A/C is always on or A/C compressor runs continuously" (See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI-3.7] .) For other symptoms, inspect the following
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| 13 |
NOTE:
Inspect cruise control systemIs cruise control system normal?
|
Yes | Go to the next step |
| No | Repair or replace the malfunctioning part | ||
| 14 | Inspect the A/F sensor (See AIR FUEL RATIO (A/F) SENSOR INSPECTION [MZI-3.7] .) Is the A/F sensor normal? |
Yes | Go to the next step |
| No | Inspect A/F sensor installation and exhaust gas leakage, service if necessary If there is no malfunction, replace the A/F sensor (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [MZI-3.7] .) |
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| 15 | Inspect the evaporative purge hose between the fuel tank and the purge valve Does fuel flow into evaporative purge hose? |
Yes | Inspect the check valve (two-way) (See FUEL TANK INSPECTION [MZI-3.7] .) |
| No | Go to the next step | ||
| 16 | Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side Plug opening end of vacuum hose Drive the vehicle Does the engine condition improve? |
Yes | Go to the next step Inspect if the purge solenoid valve is stuck open mechanically Inspect the evaporative emission control system |
| No | Go to the next step | ||
| 17 | Visually inspect the CMP sensor and projections of camshaft pulley Are CMP sensor and projections of camshaft pulley normal? |
Yes | Go to the next step |
| No | Replace the malfunctioning part | ||
| 18 | Is the engine compression correct? | Yes | Inspect the PCV valve. If the PCV valve is normal, inspect the following
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| No | Inspect for cause | ||
| 19 |
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