Home

< Previous   Next >

2008 - MX-5 - Engine

DTC P0123 [LF]



DTC P0123

TP sensor No.1 circuit high input

DETECTION CONDITION

  • If the PCM detects the TP sensor No.1 voltage is to be above 4.9 V after ignition switch to the ON position, PCM determines that TP sensor No.1 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 cycles.

  • 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

  • TP sensor No.1 malfunction

  • Connector or terminal malfunction

  • Open circuit in wiring harness between throttle body terminal C and PCM terminal 2AP

  • Open circuit in wiring harness between throttle body terminal F and PCM terminal 2AK

  • Short to constant voltage supply circuit in wiring harness between throttle body terminal F and PCM terminal 2AK

  • 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 THROTTLE BODY CONNECTION FOR POOR CONNECTION
  • Disconnect the throttle body 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 9.

No

Go to the next step.

4

INSPECT TP SENSOR NO.1

Yes

Go to the next step.

No

Replace the throttle body, then go to Step 9.

(See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [LF].)

5

INSPECT TP SENSOR NO.1 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY
  • Turn the ignition switch to the ON position (Engine off).

  • Measure the voltage between throttle body terminal F (wiring harness-side) and body ground.

  • Is the voltage above 4.9 V?

Yes

Repair or replace for a short to power supply. Then, go to Step 9.

No

Go to the next step.

6

VERIFY TP SENSOR NO.1 SIGNAL CIRCUIT FOR SHORT TO CONSTANT VOLTAGE CIRCUIT
  • Inspect for continuity between throttle body terminals E and F (wiring harness-side).

  • Is there continuity?

Yes

Repair or replace suspected wiring harness, then go to Step 9.

No

Go to the next step.

7

INSPECT PCM CONNECTOR FOR POOR CONNECTION
  • 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 9.

No

Go to the next step.

8

VERIFY TP SENSOR NO.1 GROUND CIRCUIT FOR OPEN CIRCUIT
  • Inspect for continuity between throttle body terminal C (wiring harness-side) and PCM terminal 2AP (wiring harness-side).

  • Is there continuity?

Yes

Repair or replace for an open circuit between TP sensor No.1 terminal C (wiring harness-side) and PCM terminal 2AP (wiring harness-side). Then, go to the step.

No

Go to the next step.

9

VERIFY TROUBLESHOOTING OF DTC P0123 COMPLETED
  • Make sure to reconnect all disconnected connectors.

  • Turn the ignition switch to the ON position (Engine off).

  • Clear the DTC from the PCM memory using the M-MDS.

  • Start the engine and warm it up completely.

  • 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.

10

VERIFY AFTER REPAIR PROCEDURE

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [LF].)

No

Troubleshooting completed.




< Previous   Next >
Back to Top
© 2012 Mazda North American Operations, U.S.A.