Mazda Protege 5. Manual - part 54

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

01–02B–36

Diagnostic procedure

End Of Sie

DTC P0112 [FS]

A3U010201084W12

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

INSPECT IAT SENSOR CONNECTOR FOR 
POOR CONNECTION

•

Turn ignition key to OFF.

•

Disconnect IAT sensor connector.

•

Check for poor connection (damaged/pulled-
out pins, corrosion, etc.).

•

Is there malfunction?

Yes Repair or replace terminal, then go to Step 6.

No

Go to next step.

4

INSPECT IAT SENSOR

•

Measure resistance between IAT sensor 
terminals A and B (part-side).

•

Is resistance below 550 ohms?

Yes Replace IAT sensor, then go to Step 6.

No

Go to next step.

5

INSPECT PCM CONNECTOR FOR POOR 
CONNECTION

•

Disconnect PCM connector.

•

Check for poor connection at terminals 39 and 
91 (damaged/pulled-out pins, corrosion, etc.).

•

Is there malfunction?

Yes Repair or replace terminal, then go to Step 6.

No

Go to next step.

6

VERIFY TROUBLESHOOTING OF DTC P0111 
COMPLETED

•

Make sure to reconnect all disconnected 
connectors.

•

Clear DTC from PCM memory using WDS or 
equivalent.

•

Start engine and run engine under FREEZE 
FRAME DATA condition.

•

Is PENDING CODE of same DTC present?

Yes Replace PCM, then go to next step.

No

Go to next step.

7

VERIFY AFTER REPAIR PROCEDURE

•

Perform “After Repair Procedure”.
(See 01–02B–9 AFTER REPAIR 
PROCEDURE [FS].)

•

Is there any DTC present?

Yes Go to applicable DTC inspection.

(See 01–02B–15 DTC TABLE [FS].)

No

Troubleshooting completed.

DTC P0112

IAT circuit low input

DETECTION 

CONDITION

•

PCM monitors IAT sensor signal at PCM terminal 39. If voltage at PCM terminal 39 is below 0.16 V, PCM 
determines that IAT sensor circuit has malfunction.

Diagnostic support note

•

This is a continuous monitor (CCM).

•

MIL illuminates if PCM detects the above malfunction condition during first drive cycle. Therefore, 
PENDING CODE is not available.

•

FREEZE FRAME DATA is available.

•

DTC is stored in PCM memory.

POSSIBLE 

CAUSE

•

IAT sensor malfunction

•

Short to ground circuit between IAT sensor terminal A and PCM terminal 39

•

IAT signal and IAT ground circuits are shorted each other.

•

PCM malfunction

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

01–02B–37

01–02B

Diagnostic procedure

DTC P0112

IAT circuit low input

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, then go to next step.

No

Go to next step.

3

INSPECT IAT SENSOR TERMINALS

•

Turn ignition key to OFF.

•

Disconnect IAT sensor connector.

•

Check for bent terminals of IAT sensor 
terminals A and B (part-side).

•

Is there malfunction?

Yes Repair or replace terminal, then go to Step 7.

No

Go to next step.

4

CLASSIFY IAT SENSOR MALFUNCTION OR 
HARNESS MALFUNCTION

•

Disconnect IAT sensor connector.

•

Measure resistance between IAT sensor 
terminals A and B (part-side).

•

Is resistance within 0.117—28.616 kilohms? 

Yes Go to next step.

No

Replace IAT sensor, then go to Step 7.

5

INSPECT IAT SIGNAL CIRCUIT FOR SHORT TO 
GROUND

•

Turn ignition key to OFF.

•

Disconnect PCM connector.

•

Check for continuity between IAT sensor 
terminal A (harness-side) and body ground.

•

Is there continuity?

Yes Repair or replace harness for short to ground, then go to 

Step 7.

No

Go to next step.

6

INSPECT IAT CIRCUITS FOR INTERMEDIATE 
SHORT

•

Check for continuity between IAT sensor 
terminals A and B (harness-side).

•

Is there continuity?

Yes Repair or replace harness for short, then go to Step 8.

No

Go to next step.

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

01–02B–38

End Of Sie

DTC P0113 [FS]

A3U010201084W13

7

VERIFY TROUBLESHOOTING OF DTC P0112 
COMPLETED

•

Make sure to reconnect all disconnected 
connectors.

•

Clear DTC from PCM memory using WDS or 
equivalent.

•

Start engine.

•

Is same DTC present?

Yes Replace PCM, then go to next step.

No

No concern is detected. Go to next step.

8

VERIFY AFTER REPAIR PROCEDURE

•

Perform “After Repair Procedure”.
(See 01–02B–9 AFTER REPAIR 
PROCEDURE [FS].)

•

Is there any DTC present?

Yes Go to applicable DTC inspection.

(See 01–02B–15 DTC TABLE [FS].)

No

Troubleshooting completed.

STEP

INSPECTION

ACTION

DTC P0113

IAT circuit high input

DETECTION 

CONDITION

•

The PCM monitors IAT sensor signal at PCM terminal 39. If voltage at PCM terminal 39 is above 4.84 V, 
PCM determines that IAT sensor circuit has malfunction.

Diagnostic support note

•

This is a continuous monitor (CCM).

•

MIL illuminates if PCM detects the above malfunction condition during first drive cycle. Therefore, 
PENDING CODE is not available.

•

FREEZE FRAME DATA is available.

•

DTC is not stored in PCM memory.

POSSIBLE 

CAUSE

•

IAT sensor malfunction

•

Open circuit between IAT sensor terminal A and PCM terminal 39

•

Short to power circuit between IAT sensor terminal A and PCM terminal 39

•

Open circuit between IAT sensor terminal B and PCM terminal 91

•

Short to power circuit between IAT sensor terminal B and PCM terminal 91

•

Poor connection at IAT sensor or PCM connector

•

PCM malfunction

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

01–02B–39

01–02B

Diagnostic procedure

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

INSPECT IAT SENSOR CONNECTOR FOR 
POOR CONNECTION

•

Turn ignition key to OFF.

•

Disconnect IAT sensor connector.

•

Check for poor connection (damaged/pulled-
out pins, corrosion, etc.).

•

Is there malfunction?

Yes Repair or replace terminal, then go to Step 10.

No

Go to next step.

4

INSPECT IAT SENSOR

•

Disconnect IAT sensor connector.

•

Measure resistance between IAT sensor 
terminals A and B (part-side).

•

Is resistance within 0.117—28.616 kilohms? 

Yes Replace IAT sensor, then go to Step 10.

No

Go to next step.

5

INSPECT IAT SENSOR SIGNAL CIRCUIT FOR 
SHORT TO POWER

•

Turn ignition key to ON (Engine OFF).

•

Measure voltage between IAT sensor terminal 
B (harness-side) and body ground.

•

Is there voltage B+?

Yes Repair or replace harness for short to power, then go to 

Step 10.

No

Go to next step.

6

INSPECT IAT SENSOR GROUND CIRCUIT FOR 
SHORT TO POWER

•

Measure voltage between IAT sensor terminal 
A (harness-side) and body ground.

•

Is voltage B+?

Yes Repair or replace harness for short to power, then go to 

Step 10.

No

Go to next step.

7

INSPECT PCM CONNECTOR POOR 
CONNECTION

•

Turn ignition key to OFF.

•

Disconnect PCM connector.

•

Inspect PCM terminal 39 and 91 (harness-side) 
for tightness using feeler tool.

•

Is there malfunction?

Yes Repair or replace terminal, then go to Step 10.

No

Go to next step.

8

INSPECT IAT SENSOR SIGNAL CIRCUIT FOR 
OPEN CIRCUIT

•

Connect breakout box with PCM disconnected.

•

Check for continuity between IAT sensor 
terminal A (harness-side) and breakout box 
terminal 39.

•

Is there continuity?

Yes Go to next step.

No

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

9

INSPECT IAT SENSOR GROUND CIRCUIT FOR 
OPEN CIRCUIT

•

Check for continuity between IAT sensor 
terminal B (harness-side) and breakout box 
terminal 91.

•

Is there continuity?

Yes Go to next step.

No

Repair or replace harness for open, then go to next step.

10

VERIFY TROUBLESHOOTING OF DTC P0113 
COMPLETED

•

Make sure to reconnect all disconnected 
connectors.

•

Clear DTC from PCM memory using WDS or 
equivalent.

•

Start engine.

•

Is same DTC present?

Yes Replace PCM, then go to next step.

No

No concern is detected. Go to next step.

11

VERIFY AFTER REPAIR PROCEDURE

•

Perform “After Repair Procedure”.
(See 01–02B–9 AFTER REPAIR 
PROCEDURE [FS].)

•

Is there any DTC present?

Yes Go to applicable DTC inspection.

(See 01–02B–15 DTC TABLE [FS].)

No

Troubleshooting completed.

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