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2008 - MX-5 - Engine

DTC P0103 [LF]



DTC P0103

MAF sensor circuit high input

DETECTION CONDITION

  • The PCM monitors the input voltage from the MAF sensor when the engine running. If the input voltage is above 4.9 V, the PCM determines that the MAF circuit has a malfunction.

    Diagnostic support note
  • This is a continuous monitor (CCM).

  • The MIL illuminates if the PCM detects the above malfunction condition during first drive cycle.

  • PENDING CODE is available if the PCM detects the above malfunction condition.

  • FREEZE FRAME DATA is available.

  • The DTC is stored in the PCM memory.

POSSIBLE CAUSE

  • MAF sensor malfunction

  • Connector or terminal malfunction

  • Short to power supply in wiring harness between MAF/IAT sensor terminal C and PCM terminal 1AK

  • Open circuit in wiring harness between MAF/IAT sensor terminal B and PCM terminal 1P

  • 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 Bulletins and/or on-line 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 MAF/IAT SENSOR CONNECTOR FOR POOR CONNECTION
  • Turn the ignition switch off.

  • Disconnect the MAF/IAT sensor connector.

  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).

  • Is there any malfunction?

Yes

Repair or replace the terminals, then go to Step 8.

No

Go to the next step.

4

INSPECT MAF SENSOR SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY
  • Turn the ignition switch to the ON position. (Engine off)

  • Measure the voltage between MAF/IAT sensor terminal C (wiring harness-side) and body ground.

  • Is the voltage B+?

Yes

Repair or replace the wiring harness, then go to Step 8.

No

Go to the next step.

5

INSPECT MAF SENSOR

Yes

Replace the MAF/IAT sensor, then go to Step 8.

(See MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION [LF].)

No

Go to the next step.

6

INSPECT PCM CONNECTOR FOR POOR CONNECTION
  • Turn the ignition switch off.

  • Disconnect the PCM connector.

  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).

  • Is there any malfunction?

Yes

Repair the terminal, then go to Step 8.

No

Go to the next step.

7

INSPECT MAF SENSOR GROUND FOR OPEN CIRCUIT
  • Remove the PCM with the PCM connector connected.

  • Inspect for continuity between MAF/IAT sensor terminal B (wiring harness-side) and body ground.

  • Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness, then go to the next step.

8

VERIFY TROUBLESHOOTING OF DTC P0103 COMPLETED
  • Make sure to reconnect all the 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.

(See PCM REMOVAL/INSTALLATION [LF].)

No

Go to the next step.

9

VERIFY AFTER REPAIR PROCEDURE

Yes

Go to the applicable DTC troubleshooting.

(See DTC TABLE [LF].)

No

Troubleshooting completed.




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