Mazda Factory OBD-II DTC P0643 Code Diagnostic Procedure

P0643 Diesel particulate filter differential pressure sensor circuit or MAP sensor circuit high input
DETECTION CONDITION
•  The PCM monitors the input signal from diesel particulate filter differential pressure sensor or MAP sensor. If the voltage from diesel particulate filter differential pressure sensor or MAP sensor is more than 5.25 V, the PCM determines that there is a malfunction in the diesel particulate filter differential pressure sensor circuit or MAP sensor circuit.
POSSIBLE CAUSE
•  Diesel particulate filter differential pressure sensor malfunction
•  MAP sensor malfunction
•  Connector or terminal malfunction
•  Short to power supply in wiring harness between diesel particulate filter differential pressure sensor terminal A and PCM terminal 207
•  Short to power supply in wiring harness between manifold absolute pressure (MAP) sensor terminal C and PCM terminal 205
•  PCM malfunction

Diagnostic procedure

STEP INSPECTION ACTION
1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
•  Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2
VERIFY RELATED REPAIR INFORMATION AVAILABILITY
•  Verify related service 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.
No
Go to the next step.
3
INSPECT MAP SENSOR CONNECTOR FOR POOR CONNECTION
•  Turn the engine switch off.
•  Disconnect the MAP sensor connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 10.
No
Go to the next step.
4
INSPECT DIESEL PARTICULATE FILTER DIFFERENTIAL PRESSURE SENSOR CONNECTOR FOR POOR CONNECTION
•  Turn the engine switch off.
•  Disconnect the diesel particulate filter differential pressure sensor connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 10.
No
Go to the next step.
5
INSPECT MAP SENSOR POWER CIRCUIT FOR SHORT TO POWER SUPPLY
•  Turn the engine switch to the ON position (Engine off).
•  Measure the voltage between the MAP sensor terminal C (wiring harness-side) the and body ground.
•  Is the voltage more than 5.25 V?
Yes
Repair or replace the wiring harness for a possible short to power supply, then go to Step 10.
No
Go to the next step.
6
INSPECT DIESEL PARTICULATE FILTER DIFFERENTIAL PRESSURE SENSOR POWER CIRCUIT FOR SHORT TO POWER SUPPLY
•  Turn the engine switch to the ON position (Engine off).
•  Measure the voltage between the diesel particulate filter differential pressure sensor terminal A (wiring harness-side) the and body ground.
•  Is the voltage more than 5.25 V?
Yes
Repair or replace the wiring harness for a possible short to power supply, then go to Step 10.
No
Go to the next step.
7
INSPECT MAP SENSOR
•  Inspect the MAP sensor.
•  Is there any malfunction?
Yes
Replace the MAP sensor, then go to Step 10.
No
Go to the next step.
8
INSPECT DIESEL PARTICULATE FILTER DIFFERENTIAL PRESSURE SENSOR
•  Inspect the diesel particulate filter differential pressure sensor.
•  Is there any malfunction?
Yes
Replace the diesel particulate filter differential pressure sensor, then go to Step 10.
No
Go to the next step.
9
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, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the terminal, then go to the next step.
No
Go to the next step.
10
VERIFY TROUBLESHOOTING OF DTC P0643 COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Start the engine.
•  Is the same DTC present?
Yes
Replace the PCM, then go to the next step.
No
Go to the next step.
11
VERIFY AFTER REPAIR PROCEDURE
•  Perform the Repair Verification Drive Mode.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
No
DTC troubleshooting completed.
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