| Mazda P1935 | BOO switch input circuit malfunction |
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DETECTION CONDITION
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• The PCM monitors the BOO switch signal from the instrument cluster. If the voltage at the instrument cluster terminal 2M remains low, the PCM determines that there is an BOO switch circuit malfunction.
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POSSIBLE CAUSE
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• BOO switch malfunction
• Poor connection of BOO switch connector or instrument cluster connector
• Short to ground in the wiring harness between BOO switch terminal A and instrument cluster terminal 2M
• Open circuit in the wiring harness between BOO switch terminal A and instrument cluster terminal 2M
• Open circuit in the wiring harness between ground and BOO switch terminal B
• 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 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 RELATED PENDING CODE OR STORED DTC
• Turn the engine switch off then to the ON position (Engine off).
• Verify the related PENDING CODE or stored DTCs.
• Is the DTC U0001, U0100, U0101, U0121, U0155 or U0405 also present?
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Yes
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Go to the applicable DTC troubleshooting.
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No
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Go to the next step.
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4
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INSPECT BOO SWITCH CONNECTOR FOR POOR CONNECTION
• Turn the engine switch off.
• Disconnect the BOO switch connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Is there malfunction?
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Yes
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Repair or replace the terminal, then go to Step 10.
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No
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Go to the next step.
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5
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INSPECT BOO SWITCH SIGNAL CIRCUIT FOR SHORT TO GROUND
• Inspect for continuity between BOO switch terminal A and ground.
• Is there continuity?
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Yes
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Repair or replace the wiring harness for short to ground, then go to the next step.
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No
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Go to the next step.
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6
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INSPECT BOO SWITCH GROUND CIRCUIT FOR OPEN CIRCUIT
• Inspect for continuity between BOO switch terminal B and ground.
• Is there continuity?
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Yes
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Go to the next step.
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No
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Repair or replace the BOO switch power circuit for open circuit, then Go to Step 10.
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7
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INSPECT BOO SWITCH
• Perform the BOO switch inspection.
• Is the BOO switch normal?
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Yes
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Go to Step 10.
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No
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Replace the BOO switch, then go to Step 10.
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8
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INSPECT INSTRUMENT CLUSTER CONNECTOR FOR POOR CONNECTION
• Turn the engine switch off.
• Disconnect the instrument cluster connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Is there malfunction?
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Yes
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Repair or replace the terminal, then go to Step 10.
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No
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Go to the next step.
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9
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INSPECT BOO SWITCH SIGNAL CIRCUIT FOR OPEN CIRCUIT
• Inspect for continuity between BOO switch terminal A and instrument cluster terminal 2M.
• Is there continuity?
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Yes
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Go to the next step.
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No
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Repair or replace the wiring harness for open circuit, then go to the next step.
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10
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VERIFY THAT DTC P1935 TROUBLESHOOTING IS COMPLETED
• Make sure to reconnect all disconnected connectors.
• Run the vehicle under the FREEZE FRAME DATA stored condition.
• Clear the DTC from the PCM memory using the M-MDS.
• Operate the brake pedal while the vehicle runs and stops 8 times alternately.
• Is 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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11
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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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