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2008 - MX-5 - Engine

DTC P0134 [LF]



DTC P0134

Front HO2S no activity detected

DETECTION CONDITION

  • The PCM monitors the front HO2S element impedance when the following conditions are met. If the front HO2S element impedance is 80 ohms or more, the PCM determines that front HO2S is not activated.

    • MONITORING CONDITIONS
    • HO2S, HO2S heater and TWC Repair Verification Drive Mode

    • Following conditions are met

      • Time from engine start is above 30 s (ECT when engine start is 20 °C {68 °F}).

    Diagnostic support note
  • This is an intermittent monitor (HO2S).

  • The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.

  • PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.

  • FREEZE FRAME DATA is available.

  • The DTC is stored in the PCM memory.

POSSIBLE CAUSE

  • Front HO2S deterioration

  • Front HO2S heater malfunction

  • Open circuit or short to ground in wiring harness between front HO2S terminal A and PCM terminal 2AD


Diagnostic procedure

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED
  • Have FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS (HO2S related) been recorded?

Yes

Go to the next step.

No

Record the FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS 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

VERIFY RELATED PENDING AND STORED DTC

NOTE:

  • If fuel monitor DTC, DTC P0132 is retrieved, ignore it until P0134 is fixed.

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

  • Verify pending and stored DTCs using the M-MDS.

  • Is other DTC present?

Yes

Go to the appropriate DTC troubleshooting procedures.

No

Go to the next step.

4

IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA
  • Is DTC P0134 on FREEZE FRAME DATA?

Yes

Go to the next step.

No

Go to troubleshooting procedures for DTC on FREEZE FRAME DATA.

(See DTC TABLE [LF].)

5

INSPECT INSTALLATION OF FRONT HO2S
  • Inspect if the front HO2S is loosely installed.

  • Is the sensor installed securely?

Yes

Go to the next step.

No

Install sensor securely, then go to Step 10.

6

INSPECT FRONT HO2S SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY CIRCUIT
  • Turn the ignition switch to OFF.

  • Disconnect the front HO2S connector.

  • Measure the voltage between front HO2S terminal A (wiring harness-side) and GND.

  • Is the voltage above 3.22 V?

Yes

Repair or replace for short to power supply circuit, then go to Step 10.

No

Go to the next step.

7

INSPECT FRONT HO2S SIGNAL CIRCUIT FOR OPEN
  • Disconnect the PCM connector.

  • Inspect for continuity between PCM terminal 2AD (wiring harness-side) and front HO2S terminal A (wiring harness-side).

  • Is there continuity?

Yes

Go to the next step.

No

Repair or replace for open circuit, then go to Step 10.

8

INSPECT FRONT HO2S HEATER

Yes

Go to the next step.

No

Replace the front HO2S, then go to Step 10.

(See FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [LF].)

9

INSPECT FRONT HO2S

Yes

Go to the next step.

No

Replace the front HO2S, then go to the next step.

(See FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [LF].)

10

VERIFY TROUBLESHOOTING OF DTC P0134 COMPLETED
  • Make sure to reconnect all disconnected connectors.

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

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

  • Perform the KOER self-test (using M-MDS) or the HO2S heater, HO2S, and TWC Repair Verification Drive Mode (not using M-MDS).

    (See KOEO/KOER SELF TEST [LF].)

    (See OBD-II DRIVE MODE [LF].)

  • Is the PENDING CODE for this DTC present?

Yes

Replace the PCM, then go to the next step.

(See PCM REMOVAL/INSTALLATION [LF].)

No

Go to the next step.

11

VERIFY AFTER REPAIR PROCEDURE

Yes

Go to the applicable DTC troubleshooting.

(See DTC TABLE [LF].)

No

Troubleshooting completed.




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