| Mazda P2554 | Throttle/fuel inhibit circuit low |
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DETECTION CONDITION
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• The PCM monitors the fuel injector operation using the fuel rail pressure signal balance while the engine is running. If the PCM detects that the fuel rail pressure decrease value at injection timing is below the threshold, the PCM determines that the fuel injector circuit voltage is low.
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POSSIBLE CAUSE
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• Fuel injector mechanical malfunction (excessive sliding resistance of valve control plunger)
• Poor connection of connector
• Fuel injector electrical malfunction (solenoid valve coil open circuit)
• Fuel pressure sensor malfunction
• PCM malfunction
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Diagnostic procedure
| STEP | INSPECTION | ACTION | |
|---|---|---|---|
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1
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VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
• Has the FREEZE FRAME DATA been recorded?
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Yes
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Go to the next step.
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No
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Record the FREEZE FRAME DATA on the repair order, then go to the next step.
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2
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VERIFY RELATED REPAIR INFORMATION AVAILABILITY
• Verify related service repair information availability.
• Is any related repair information available?
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Yes
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Perform repair or diagnosis according to the available repair information.
If the vehicle is not repaired, go to the next step.
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No
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Go to the next step.
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3
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VERIFY CURRENT SIGNAL STATUS: IS CONCERN INTERMITTENT OR CONSTANT
• Connect the M-MDS to DLC-2.
• Clear the DTC from the PCM memory using the M-MDS.
• Perform the KOEO or KOER self-test.
• Is the same DTC retrieved?
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Yes
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Go to the next step.
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No
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Intermittent concern exists.
Perform the “INTERMITTENT CONCERN TROUBLESHOOTING”.
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4
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IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA
• Is P0191, P0192, P0193, P0201, P0202, P0203 or P0204 on FREEZE FRAME DATA?
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Yes
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Go to the applicable DTC inspection.
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No
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Go to the next step.
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5
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INSPECT FUEL INJECTOR AND FUEL PRESSURE SENSOR CONNECTORS FOR POOR CONNECTION
• Turn the engine switch off.
• Disconnect the all fuel injectors and fuel pressure sensor connectors.
• Inspect for poor connection (such as damaged/pulled-out pins, and corrosion).
• Is there any malfunction?
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Yes
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Repair or replace the terminal, then go to Step 11.
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No
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Go to the next step.
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6
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INSPECT FUEL INJECTOR COIL RESISTANCE
• Measure the resistance between fuel injector terminal A and B.
• Is the resistance approx. 0.7 ohms (20 °C {68 °F})?
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Yes
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Go to the next step.
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No
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Replace the fuel injector, then go to Step 11.
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7
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INSPECT FUEL PRESSURE SENSOR
• Inspect the fuel pressure sensor.
• Is the fuel pressure sensor normal?
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Yes
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Go to the next step.
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No
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Replace the common rail, then go to Step 11.
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8
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INSPECT FUEL INJECTORS FOR LEAKAGE
• Perform the fuel leakage inspection.
• Are all fuel injector normally?
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Yes
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Go to the next step.
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No
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Replace the suspect fuel injector, then go to Step 11.
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9
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VISUALLY INSPECT FUEL INJECTORS
• Perform the fuel leakage inspection.
• Are all fuel injectors normal?
• Is there any malfunction detected?
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Yes
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Replace the suspect fuel injector, then go to Step 11.
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No
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Go to the next step.
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10
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INSPECT PCM CONNECTOR FOR POOR CONNECTION
• Turn the engine switch off.
• Disconnect the PCM connector.
• Inspect for poor connection (such as damaged/pulled-out pins, and corrosion).
• Is there any malfunction?
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Yes
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Repair or replace terminal, then go to the next step.
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No
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Go to the next step.
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11
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VERIFY THAT DTC P2554 TROUBLESHOOTING IS COMPLETED
• Make sure to reconnect all disconnected connectors.
• Clear the DTC from the PCM memory using the M-MDS.
• Run the vehicle under the FREEZE FRAME DATA stored condition.
• Is the same DTC present?
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Yes
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Replace the PCM, then go to the next step.
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No
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Go to the next step.
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12
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VERIFY AFTER REPAIR PROCEDURE
• Perform the after repair procedure.
• Are any DTCs present?
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Yes
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Go to the applicable DTC inspection.
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No
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DTC troubleshooting completed.
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