Mazda 6. Manual - part 146

F–106

ON-BOARD DIAGNOSTIC 

2

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.

No

Go to next step.

3

VERIFY RELATED PENDING AND STORED 
DTCs

• 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.

No

Go to next step.

4

IDENTIFY TRIGGER DTC FOR FREEZE FRAME 
DATA

• Is DTC P0131 and P0132 on FREEZE FRAME 

DATA?

Yes Go to next step.

No

Go to troubleshooting procedures for DTC on FREEZE 
FRAME DATA.

5

VERIFY CURRENT INPUT SIGNAL STATUS - IS 
CONCERN INTERMITTENT OR CONSTANT

• Warm-up engine.

• Access O2S11 for P0131 and P0132 PID using 

WDS or equivalent.

• Verify PID while racing engine (in PARK (ATX) 

or NEUTRAL (MTX)).

• Is PID reading okay?

— More than 0.45 V when suddenly depress 

accelerator pedal (rich condition)

— Less than 0.45 V just after release of 

accelerator pedal (lean condition)

Yes Go to next step.

No

Replace front HO2S, then go to Step 19.

6

INSPECT LONG TERM FUEL TRIM

• Access LONGFT1 for P0131 and P0132 PID 

using WDS or equivalent.

• Compare it with FREEZE FRAME DATA 

recorded at Step1.

• Was it decreased?

Yes Engine is driven under rich condition. Go to next step.

No

Engine is driven under lean condition. Go to step 9.

7

INSPECT FUEL LINE PRESSURE (EXCESSIVE 
FUEL LINE PRESSURE)

• Turn ignition key to OFF.

• Inspect fuel line pressure.

(See 

F–20 FUEL LINE PRESSURE 

INSPECTION

.)

• Is fuel line pressure okay?

Yes Go to next step.

No

Inspect following parts and repair or replace if necessary:

• Fuel pump maximum pressure

• Fuel return pipe for clogged

— If all items above are okay, replace pressure 

regulator. Then, go to Step 19.

8

INSPECT PURGE SOLENOID VALVE FOR 
STUCK OPEN

• Turn ignition key to OFF.

• Disconnect both hoses from purge solenoid 

valve.

• Blow air through purge solenoid valve.

• Does air blow through?

Yes Replace purge solenoid valve.

No

Go to Step 13.

9

INSPECT PCV VALVE OPERATION

•  Inspect PCV valve operation.

(See 

F–41 PCV VALVE INSPECTION

.)

• Is PCV valve okay?

Yes Go to next step.

No

Replace PCV, then go to Step 19.

10

INSPECT FUEL LINE PRESSURE (LOW FUEL 
LINE PRESSURE)

• Turn ignition key to OFF.

• Inspect fuel line pressure.

(See 

F–20 FUEL LINE PRESSURE 

INSPECTION

.)

• Is fuel line pressure okay?

Yes Go to step 13.

No

Go to next step.

11

INSPECT FUEL PUMP MAXIMUM PRESSURE

• Stop engine.

• Turn ignition key to ON (Engine OFF).

• Perform fuel pump maximum pressure test.

(See 

F–20 FUEL LINE PRESSURE 

INSPECTION

.)

• Is fuel pump maximum pressure okay?

Yes Go to next step.

No

Inspect fuel pump circuit for open or poor connection.

• Repair or replace suspected circuit.

• If circuit is okay, replace fuel pump. 

 Then go to Step 19.

STEP

INSPECTION

ACTION

ON-BOARD DIAGNOSTIC 

F–107

F

12

INSPECT FUEL LINE FROM FUEL PUMP TO 
FUEL DELIVERY PUMP

• Visually inspect fuel line for any leakage.

• Is any fuel leakage found?

Yes Replace suspected fuel line, then go to Step 19.

No

Inspect fuel filters for following:

• Restriction or clogging at fuel filter (high-pressure side).

• Foreign materials or stain inside fuel filter (low-pressure 

side)
— If restriction or clogging is found at fuel filter (high-

pressure side), replace fuel filter.

— If foreign materials or stain is found inside fuel filter 

(low-pressure side), clean of fuel tank and filter.

— If all items above are okay, replace pressure 

regulator. Then, go to Step 19.

13

CHECK IGNITION COIL OPERATION

• Perform spark test.

(See 

F–232 Spark Test

)

• Do all cylinders show blinking condition?

Yes Go to step 16.

No

Go to next step.

14

INSPECT POWER SUPPLY TERMINAL AT 
IGNITION COIL CONNECTOR

• Disconnect ignition coil connector.

• Turn ignition key to ON (Engine OFF).

• Measure voltage between ignition coil 

connector terminal D (harness-side) and body 
ground.

• Is the voltage reading B+?

Yes Go to next step.

No

Check for open circuit between ignition coil connector and 
ignition switch.
Repair or replace wiring harness, then go to Step 19.

15

INSPECT IGNITION COIL RESISTANCE

• Check ignition coil resistance.

(See 

G–9 IGNITION COIL INSPECTION

.)

• Is coil resistance okay?

Yes Go to next step.

No

Replace ignition coil, then go to Step 19.

16

INSPECT ENGINE COMPRESSION

• Inspect engine compression.

(See 

B–9 COMPRESSION INSPECTION

.)

• Is it okay?

Yes Go to next step.

No

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

17

INSPECT FUEL INJECTOR OPERATION

• Turn ignition key to OFF.

• Inspect injector.

(See 

F–31 FUEL INJECTOR INSPECTION

.)

• Is injector okay?

Yes Go to next step.

No

Replace injector, then go to Step 19.

18

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 to head gasket or other areas 

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

No

Go to next step.

STEP

INSPECTION

ACTION

F–108

ON-BOARD DIAGNOSTIC 

End Of Sie

DTC P0133

A6E397001084W23

Diagnostic procedure

19

VERIFY TROUBLESHOOTING OF DTC P0131 or 
P0132 COMPLETED

• Make sure to reconnect all disconnected 

connectors.

• Turn ignition key to ON (Engine OFF).

• Clear DTC from memory using WDS or 

equivalent.

• Start engine.

• Access ECT and RPM PIDs using WDS or 

equivalent.

• Make sure that ECT PID is above 80 °C {176 

°F}.

• Increase and keep engine speed above 1,500 

rpm for at least 1 min.

• Is pending code the same as DTC present?

Yes Replace PCM, then go to next step.

(See 

F–43 PCM REMOVAL/INSTALLATION

.)

No

Go to next step.

20

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

.)

No

Troubleshooting completed.

STEP

INSPECTION

ACTION

DTC P0133

Front HO2S circuit malfunction

DETECTION 

CONDITION

• PCM monitors inversion cycle period, lean-to-rich response time and rich-to-lean response time of the 

sensor. PCM calculates the average of the inversion cycle period-specified inversion cycles, average 
response time from lean-to-rich, and from rich-to-lean when following conditions are met. If any exceeds 
threshold, PCM determines that circuit has malfunction.

MONITORING CONDITIONS

— Drive mode 3
— Following conditions are met:

• Calculation load 14.8—59.4 % (at 2,000 rpm).

• Engine speed 1,410—4,000 rpm (MTX)

• Engine speed 1,190—4,000 rpm (ATX)

• Vehicle speed is above 3.76 km/h

• Engine coolant temperature is above -10 °C {14 °F}

• Front HO2S signal inversion cycle is above 10 cycles

Diagnostic support note

• This is an intermittent monitor. (OXYGEN SENSOR)

• 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.

• DIAGNOSTIC MONITORING TEST RESULTS is available.

• 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

• Pressure regulator malfunction

• Fuel pump malfunction

• Fuel filter clogged or restricted

• Fuel leakage on fuel line from fuel distribution pipe and fuel pump

• Leakage exhaust system

• Purge solenoid valve malfunction

• Purge solenoid hoses improper connection

• Insufficient compression

• Engine malfunction

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA HAS BEEN 
RECORDED

• Has FREEZE FRAME DATA been recorded?

Yes Go to next step.

No

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

2

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.

No

Go to next step.

ON-BOARD DIAGNOSTIC 

F–109

F

3

VERIFY RELATED PENDING AND STORED 
DTCS

• Turn ignition key to OFF, then ON (Engine 

OFF).

• Verify pending and /or stored DTCs using WDS 

or equivalent.

• Is DTC P0443 also present?

Yes Go to DTC P0443 troubleshooting procedures, then go to 

Step 13.

No

Go to next step.

4

IDENTIFY TRIGGER DTC FOR FREEZE FRAME 
DATA

• Is DTC P0133 on FREEZE FRAME DATA?

Yes Go to next step.

No

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

F–67 DTC TABLE

.)

5

VERIFY CURRENT INPUT SIGNAL STATUS

• Warm up engine.

• Access O2S11 PID using WDS or equivalent.

• Inspect PID under following accelerator pedal 

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

• 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 8.

No

Go to next step.

6

INSPECT INSTALLATION OF FRONT HO2S

• Inspect if front HO2S is loosely installed.

• Is sensor installed securely?

Yes Go to next step.

No

Retighten sensor, then go to Step 13.

7

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 

13.

No

Replace sensor, then go to Step 13.

8

INSPECT LONG TERM FUEL TRIM

• Access LONGFT1 PIDs

• Compare it with FREEZE FRAME DATA 

recorded at Step 1.

• Is it below FFD value?

Yes Engine is driven under rich condition. Go to next step.

No

Engine is driven under lean condition. Go to step 10.

9

INSPECT FUEL LINE PRESSURE (Excessive 
fuel line pressure)

• Turn ignition key to OFF.

• Inspect fuel line pressure while engine running.

(See 

F–20 FUEL LINE PRESSURE 

INSPECTION

.)

• Is fuel line pressure okay?

Yes Go to next step.

No

Inspect fuel pump maximum pressure and fuel return pipe 
for clogging.
(See 

F–25 FUEL PUMP UNIT INSPECTION

.)

• If any problem is found, repair or replace suspected 

parts.

• If all items above are okay, replace fuel pump unit.

Then go to Step 13.

10

INSPECT FUEL LINE PRESSURE (Low fuel line 
pressure)

• Turn ignition key to OFF.

• Inspect fuel line pressure while engine running.

(See 

F–20 FUEL LINE PRESSURE 

INSPECTION

.)

• Is fuel line pressure okay?

Yes Go to step 13.

No

Go to next step.

11

INSPECT FUEL LINE FROM FUEL PUMP TO 
FUEL DELIVERY PIPE

• Visually inspect fuel line for any leakage.

• Is any fuel leakage found?

Yes Replace suspected fuel line, then go to Step 13.

No

Inspect fuel filters for following:

• Restriction or clogging at fuel filter (high-pressure side)

• Foreign materials or stain inside fuel filter (low-pressure 

side)

Perform following actions according to result.

• If restriction or clogging is found at fuel filter (high-

pressure side), replace fuel filter.

• If foreign material or stain is found inside fuel filter (low-

pressure side), clean of fuel tank and filter.

• If all items above are okay, replace pressure regulator.

Then go to Step 13.

STEP

INSPECTION

ACTION