Mazda Protege 5. Manual - part 22

ON-BOARD DIAGNOSTIC [ENGINE CONTROL SYSTEM (ZM)]

01–02A–54

End Of Sie

5

INSPECT HO2S (REAR) SIGNAL CIRCUIT FOR 
SHORT TO POWER SUPPLY CIRCUIT

•

Turn ignition key to OFF.

•

Disconnect HO2S (rear) connector.

•

Turn ignition key to ON (Engine OFF).

•

Measure voltage between HO2S (rear) 
terminal A (harness-side) and body ground.

•

Is any voltage reading?

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

No

Go to next step.

6

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 position).

•

Does PID reading stay above 0.45 V?

Yes Replace HO2S (rear), then go to next step.

No

Go to next step.

7

VERIFY TROUBLESHOOTING OF DTC P0138 
COMPLETED

•

Make sure to reconnect all disconnected 
connectors.

•

Turn ignition key to ON (Engine OFF).

•

Clear DTC from memory using WDS or 
equivalent.

•

Run OBD-II DRIVE MODE 1 and 3.

•

Is PENDING CODE of same DTC present?

Yes Replace PCM, then go to next step.

No

Go to next step.

8

VERIFY AFTER REPAIR PROCEDURE

•

Perform “After Repair Procedure”.
(See 01–02A–10 AFTER REPAIR 
PROCEDURE [ZM].)

•

Is there any DTC present?

Yes Go to applicable DTC inspection.

(See 01–02A–15 DTC TABLE [ZM].)

No

Troubleshooting completed.

STEP

INSPECTION

ACTION

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ON-BOARD DIAGNOSTIC [ENGINE CONTROL SYSTEM (ZM)]

01–02A–55

01–02A

DTC P0140 [ZM]

A3U010201084W49

Diagnostic procedure

DTC P0140

HO2S (rear) circuit no activity detected

DETECTION 

CONDITION

•

PCM monitors input voltage from HO2S (rear) when the following monitoring conditions are met. If input 
voltage from sensor never exceeds 0.55 V for 30 seconds, PCM determines that sensor circuit is not 
activated.

MONITORING CONDITIONS

— Drive mode 3
— 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.

•

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

•

FREEZE FRAME DATA is available.

•

DTC is stored in PCM memory.

POSSIBLE 

CAUSE

•

HO2S (rear) deterioration

•

HO2S (rear) heater malfunction

•

Leakage from exhaust system

•

Open or short to ground circuit between HO2S (rear) terminal A and PCM terminal 35

•

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 REPAIR INFORMATION 
AVAILABILITY

•

Check for related Service Bulletins availability.

•

Is any related repair information available?

Yes Perform repair or diagnosis according to available repair 

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 start engine.

•

Verify pending and stored DTCs using WDS or 
equivalent.

•

Is other DTC present except P1170?

Yes Go to appropriate DTC troubleshooting procedures.

(See 01–02A–15 DTC TABLE [ZM].)

No

Go to next step.

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ON-BOARD DIAGNOSTIC [ENGINE CONTROL SYSTEM (ZM)]

01–02A–56

4

IDENTIFY TRIGGER DTC FOR FREEZE FRAME 
DATA

•

Is DTC P0140 on FREEZE FRAME DATA?

Yes Go to next step.

No

Go to troubleshooting procedures for DTC on FREEZE 
FRAME DATA.
(See 01–02A–15 DTC TABLE [ZM].)

5

VERIFY CURRENT INPUT SIGNAL STATUS

•

Warm up engine.

•

Access O2S12 PID using WDS or equivalent.

•

Verify PID while racing engine at least 10 
times (in neutral position).

•

Is PID reading okay?
— More than 0.55 V at least once during 

engine racing.

Yes Go to Step 8.

No

Go to next step.

6

INSPECT INSTALLATION OF HO2S (REAR)

•

Check if HO2S (rear) is loosely installed.

•

Is sensor installed securely?

Yes Go to next step.

No

Install sensor securely, then go to Step 10.

7

INSPECT EXHAUST SYSTEM FOR GAS 
LEAKAGE

•

Visually check if any gas leakage is found 
between exhaust pipe and HO2S (rear).

•

Is there any gas leakage?

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

10.

No

•

Inspect for open or short to ground circuit between 
HO2S (rear) terminal A (harness-side) and PCM 
terminal 35 (harness-side).
— Repair or replace harness if necessary.

•

If all items above are okay, replace HO2S (rear).

Then go to Step 10.

8

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 10.

No

Go to next step.

9

INSPECT ENGINE COMPRESSION

•

Inspect engine compression.
(See 01–10A–8 COMPRESSION 
INSPECTION [ZM].)

•

Is it okay?

Yes Go to next step.

No

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

10

VERIFY TROUBLESHOOTING OF DTC P0140 
COMPLETED

•

Make sure to reconnect all disconnected 
connectors.

•

Turn ignition key to ON (Engine OFF).

•

Clear DTC from memory using WDS or 
equivalent.

•

Access RPM and ECT PIDs using WDS or 
equivalent.

•

Verify that ECT PID is reading above 80 

°°°°

C 

{176 

°°°°

F}.

•

Increase engine speed above 1,500 rpm 
(RPM PID reading) for more than 30 
seconds.

•

Is PENDING CODE of same DTC present?

Yes Replace PCM, then go to next step.

No

Go to next step.

STEP

INSPECTION

ACTION

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ON-BOARD DIAGNOSTIC [ENGINE CONTROL SYSTEM (ZM)]

01–02A–57

01–02A

End Of Sie

DTC P0171 [ZM]

A3U010201084W50

Diagnostic procedure

11

VERIFY AFTER REPAIR PROCEDURE

•

Perform “After Repair Procedure”.
(See 01–02A–10 AFTER REPAIR 
PROCEDURE [ZM].)

•

Is there any DTC present?

Yes Go to applicable DTC inspection.

(See 01–02A–15 DTC TABLE [ZM].)

No

Troubleshooting completed.

STEP

INSPECTION

ACTION

DTC P0171

Fuel trim system too lean

DETECTION 

CONDITION

•

PCM monitors short term fuel trim (SHRTFT) and long term fuel trim (LONGFT) values when DRIVE 
MODE 1 is run. If fuel trim exceeds preprogrammed criteria, PCM determines that the fuel system is too 
lean.

Diagnostic support note

•

This is a continuous monitor. (FUEL SYSTEM) 

•

MIL illuminates if PCM detects the above malfunction conditions in two consecutive drive cycles.

•

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

•

FREEZE FRAME DATA is available.

•

DTC is stored in PCM memory.

POSSIBLE 

CAUSE

•

Misfire

•

HO2S (front) deterioration

•

HO2S (front) heater malfunction

•

PRC solenoid valve malfunction

•

Pressure regulator malfunction

•

Fuel pump malfunction

•

Fuel filter clogged or restricted

•

Fuel leakage on fuel line from fuel delivery pipe and fuel pump

•

Fuel return hose clogged

•

Leakage from exhaust system

•

Purge solenoid valve malfunction

•

Purge solenoid hoses improper connection

•

Insufficient compression

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 REPAIR INFORMATION 
AVAILABILITY

•

Check for related Service Bulletins availability.

•

Is any related repair information available?

Yes Perform repair or diagnosis according to available repair 

information.

•

If vehicle is not repaired, go to next step.

No

Go to next step.

3

VERIFY RELATED PENDING CODE OR 
STORED DTCS

•

Turn ignition key to OFF, then start engine.

•

Verify related PENDING CODE or stored 
DTCs.

•

Are other DTCs present?

Yes If misfire DTC is present, go to Step 8.

If other DTC is present, go to appropriate DTC 
troubleshooting procedures.
(See 01–02A–15 DTC TABLE [ZM].)

No

If drivability concern is present, go to Step 8.
If not, go to next step.

4

IDENTIFY TRIGGER DTC FOR FREEZE FRAME 
DATA

•

Is DTC P0171 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 
(IGNITION KEY TO ON/IDLE)

•

Access ECT, MAF, TP and VS PIDs using 
WDS or equivalent.
(See 01–40A–8 PID/DATA MONITOR table 
(Reference).)

•

Is there any signal that is far out 
of specification when ignition key is ON and 
engine runs?

Yes Inspect suspected sensor and excessive resistance in 

related wiring harnesses. Repair or replace if necessary. 
Then go to Step 20.

No

Go to next step.

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