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Mazda 6. Manual - part 147

F–110

ON-BOARD DIAGNOSTIC

End Of Sie

DTC P0134

A6E397001084W24

INSPECT SEALING OF ENGINE COOLANT
PASSAGE

Warning
• Removing radiator cap when radiator is

hot is dangerous. Scalding coolant and
steam may shoot out and cause serious
injury.

• When removing radiator cap, wrap a

thick cloth around and turn it slowly.

• Remove radiator cap.

• Implement procedure to bleed air from engine

coolant, then run engine at idle.

• Is there any small bubble, which makes engine

coolant white at filling opening?

Note

• Large bubbles are normal since they are

remaining air coming out from engine
coolant passage.

Yes Air gets in from poor sealing on head gasket or other areas

between combustion chamber and engine coolant
passage.
Repair or replace faulty parts, then go to next step.

Go to next step.

VERIFY TROUBLESHOOTING OF DTC P0133
COMPLETED

• Make sure to reconnect all disconnected

connectors.

• Turn ignition switch to ON (Engine OFF)

• Clear DTC from memory using WDS or

equivalent generic OBD function.

• Run OBD drive mode.

• Is PENDING CODE the same as DTC

present?.

Yes Replace PCM, then go to next step.

(See

F–43 PCM REMOVAL/INSTALLATION

Go to next step.

VERIFY AFTER REPAIR PROCEDURE

• Perform “After Repair Procedure”.

(See

F–66 AFTER REPAIR PROCEDURE

• Is there any DTC present?

Yes Go to applicable DTC troubleshooting.

(See

F–67 DTC TABLE

Troubleshooting completed.

STEP

INSPECTION

ACTION

DTC P0134

Front HO2S circuit no activity detected

DETECTION

CONDITION

• PCM monitors input voltage from front HO2S when the following conditions are met. If input voltage from

sensor never exceed 0.55 V for 83.2 s, PCM determines that sensor circuit is not activated.

MONITORING CONDITIONS

— HO2S, HO2S heater and TWC repair verification drive mode
— Following conditions are met

• Engine speed is above 1,500 rpm.

• Engine coolant temperature is above 80 °C {176 °F}.

Diagnostic support note

• This is a continuous monitor (CCM).

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

• FREEZE FRAME DATA is available.

• DTC is stored in the PCM memory.

POSSIBLE

CAUSE

• Front HO2S deterioration

• Front HO2S heater malfunction

• Leakage exhaust system

• Open or short to ground circuit between front HO2S terminal A and PCM terminal 1AB

• Insufficient compression

• Engine malfunction

ON-BOARD DIAGNOSTIC

F–111

Diagnostic procedure

STEP

INSPECTION

ACTION

PERFORM DTC CONFIRMATION PROCEDURE

• Perform DTC CONFIRMATION PROCEDURE.

(See

F–66 DTC CONFIRMATION

PROCEDURE

• Is same DTC present?

Yes Go to next step.

Intermittent concern exists. Go to INTERMITTENT
CONCERN TROUBLESHOOTING procedure.
(See

F–227 INTERMITTENT CONCERN

TROUBLESHOOTING

VERIFY RELATED PENDING AND STORED
DTCS

Note

• If fuel monitor DTC, DTC P0131or P0132 is

retrieved, ignore it until P0134 is fixed.

• Turn ignition key to OFF, then ON (Engine

OFF).

• Verify pending and stored DTCs using WDS or

equivalent.

• Is other DTC present?

Yes Go to appropriate DTC troubleshooting procedures.

Go to next step.

IDENTIFY TRIGGER DTC FOR FREEZE FRAME
DATA

• Is DTC P0134 on FREEZE FRAME DATA?

Yes Go to next step.

Go to troubleshooting procedures for DTC on FREEZE
FRAME DATA.
(See

F–67 DTC TABLE

VERIFY CURRENT INPUT SIGNAL STATUS

• Warm up engine.

• Access O2S11 PID using WDS or equivalent.

• Verify PID while racing engine (in NEUTRAL

(MTX) or PARK (ATX)).

• Is PID reading okay?

— More than 0.55 V when suddenly depress

accelerator pedal (rich condition).

— Less than 0.55 V just after release of

accelerator pedal (lean condition)

Yes Go to step 7.

Go to next step.

INSPECT INSTALLATION OF FRONT HO2S

• Check if front HO2S is loosely installed.

• Is sensor installed securely?

Yes Go to next step.

Install sensor securely, then go to Step 9.

DTC P0134

Front HO2S circuit no activity detected

F–112

ON-BOARD DIAGNOSTIC

End Of Sie

DTC P0138

A6E397001084W25

INSPECT GAS LEAKAGE FROM EXHAUST
SYSTEM

• Visually check if any gas leakage is found

between exhaust manifold and front HO2S.

• Is there any gas leakage?

Yes Repair or replace any faulty exhaust parts, then go to Step

• Inspect the following harnesses for open or short to

ground circuit, repair or replace harness if necessary
— Front HO2S terminal A (harness-side) to PCM

terminal 1AB (harness-side)

• Repair or replace harness if necessary.

• If all items above are okay, replace faulty sensor.

Then go to Step 9.

INSPECT SEALING OF ENGINE COOLANT
PASSAGE

Warning
• Removing radiator cap when radiator is

hot is dangerous. Scalding coolant and
steam may shoot out and cause serious
injury.

• When removing radiator cap, wrap a

thick cloth around and turn it slowly.

• Remove radiator cap.

• Implement procedure to bleed air from engine

coolant, then run engine at idle.

• Is there any small bubble, which makes engine

coolant white at filling opening?

Note

• Large bubbles are normal since they are

remaining air coming out from engine
coolant passage.

Yes Air gets in from poor sealing on head gasket or other areas

between combustion chamber and engine coolant
passage.
Repair or replace faulty parts, then go to Step 9.

Go to next step.

INSPECT ENGINE COMPRESSION

• Inspect engine compression.

(See

B–9 COMPRESSION INSPECTION

• Is it okay?

Yes Go to next step.

Implement engine overhaul for repairs, then go to next
step.

VERIFY TROUBLESHOOTING OF DTC P0134
COMPLETED

• Make sure to reconnect all disconnected

connectors.

• Turn ignition key to ON (Engine OFF).

• Clear DTC from memory using WDS or

equivalent.

• Perform KOER self-test.

(See

F–66 KOEO/KOER SELF-TEST

• Is same DTC present?

Yes Replace PCM, then go to next step.

(See

F–43 PCM REMOVAL/INSTALLATION

Go to next step.

VERIFY AFTER REPAIR PROCEDURE

• Perform “After Repair Procedure”.

(See

F–66 AFTER REPAIR PROCEDURE

• Is there any DTC present?

Yes Go to applicable DTC troubleshooting.

(See

F–67 DTC TABLE

Troubleshooting completed.

STEP

INSPECTION

ACTION

DTC P0138

Rear HO2S circuit high input

DETECTION

CONDITION

• PCM monitors input voltage from rear HO2S. If input voltage from rear HO2S sensor is above 0.45 V for 7

s during deceleration fuel cut, PCM determines that circuit input is high.

Diagnostic support note

• This is a continuous monitor (CCM).

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

• FREEZE FRAME DATA is available.

• DTC is stored in the PCM memory.

POSSIBLE

CAUSE

• Rear HO2S malfunction

• Short to power circuit in wiring between rear HO2S terminal A and PCM terminal 1Y

ON-BOARD DIAGNOSTIC

F–113

Diagnostic procedure

STEP

INSPECTION

ACTION

VERIFY FREEZE FRAME DATA HAS BEEN
RECORDED

• Has FREEZE FRAME DATA been recorded?

Yes Go to next step.

Record FREEZE FRAME DATA on repair order, then go to
next step.

VERIFY RELATED SERVICE INFORMATION
AVAILABILITY

• Check for related Service Information

availability.

• Is any related Service Information available?

Yes Perform repair or diagnosis according to available Service

Information.

• If vehicle is not repaired, go to next step.

Go to next step.

VERIFY RELATED PENDING OR STORED
DTCS

• Turn ignition key to OFF, then ON (Engine

OFF).

• Verify pending code or stored DTCs using

WDS or equivalent.

• Is other DTC present?

Yes Go to appropriate DTC troubleshooting procedures.

(See

F–67 DTC TABLE

Go to next step.

IDENTIFY TRIGGER DTC FOR FREEZE FRAME
DATA

• Is DTC P0138 on FREEZE FRAME DATA?

Yes Go to next step.

Go to troubleshooting procedures for DTC on FREEZE
FRAME DATA.
(See

F–67 DTC TABLE

INSPECT REAR HO2S SIGNAL CIRCUIT FOR
SHORT TO POWER SUPPLY CIRCUIT

• Turn ignition key to OFF.

• Disconnect rear HO2S connector.

• Turn ignition key to ON (Engine OFF).

• Measure voltage between rear HO2S terminal

A (harness-side) and body ground.

• Is any voltage reading?

Yes Replace short to power supply circuit, then go to Step 7.

Go to next step.

VERIFY CURRENT INPUT SIGNAL STATUS

• Start engine.

• Access O2S12 PID using WDS or equivalent.

• Verify PID while racing engine at least 10

times (in NEUTRAL (MTX) or PARK (ATX)).

• Does PID reading stay above 0.45 V?

Yes Repair or replace sensor, then go to next step.

Go to next step.

DTC P0138

Rear HO2S circuit high input

Content .. 145 146 147 148 ..