Service Bulletin

Mazda North American Operations
Irvine, CA 92618-2922

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© 2013 Mazda Motor of America, Inc.
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Subject:

:Bulletin No:

01-025/13

Last Issued:

08/22/2013

MIL ON WITH OTC P0139

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APPLICABLE MODEL(S)NINS
2010Mazda5

DESCRIPTION
Some vehicles may experience the MIL on with OTC P0139 (H02S circuit malfunction) stored in PCM memory.
The PCM:
1. Monitors for a time-out malfunction (when H02S remains above 0.2V for longer than a specified period of
time during fuel cut control).
2. Measures the amount of time from when conditions are met until H02S output voltage drops below 0:.2V.'.
3. Determines a H02S timeout malfunction when the detected time is more than 4 seconds· for 2. of .3 times,
This may be caused by carbon forming inside the Electric Throttle Body (ETB) which:
1. Reduces the air intake amount during deceleration (with fuel cut).
2. Allows fuel to remain around the H02$.

3. Causes detection ofP0139 (H02S.time-out fail).
Customers having this concern should have their vehicle repaired using the following repair procedure. ··

REPAIR PROCEDURE
1. Verify customer concern.
2. Perform the following Diagnosis Procedure to determine if P0139 is caused by carbon accumulation in the
throttle body. If the diagnosis results indicate carbon accumulation. clean the throttle body according tO the
following Cleaning Procedure.

NOTE: If the engine idle speed drops, OTC P0841 (malfunction within the ATF pressure circuit) may be
detected. If this happens, clear the OTC. Since the A/T oil pump speed drops if the engine idle
speed drops, the ATF pressure decrease causes the OTC detection.
3. Repeat steps 3 and 4 of the Diagnosis Procedure to confirm the engine idle condition when the "test mode"
is ON.

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CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be pelformed by "do-it-yourselfers.» Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bµlletfn without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electtonic Or mechanical-including photocopying and recording and the use of any kind of information storage and retrieval system -without permission in
writing.

Bulletin No: 01-025/13

Last Issued: 08/22/2013

© 2013 Mazda Motor of America, Inc.

3. Select the following simulation items from the-PJO table, then select tk;k.

ARPMDES

Target engine speed

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Engine coolant temperature

.. ECT •...

" LOAD

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EQ RAT11

NF sensor

MAF

Mass airflow sensor

MAP

Manifold absolute pressure

RPM

Engine speed

SPARKADV

Ignition timing

Test

Test mode

TP1

TP2

.Part Name

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Absolute engine load

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Throttle valve position No. 1

4. Warm up the engine (engine coolant temperature is 85 °C ( 185°F) or more}, and leave it at idle with no load
applied (in Park or Neutral with NC, PIS,
and all electrical
loads off);
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5. Keep a record of the engine idle speed when the "test mode" is ON for 15 seconds and then when the "test
mode" is OFF without a break. Capture the" data as· a session file.·
6. Check the engine idle condition when the "test mode" is ON.
Idle speed: 650-750 rpm
The engine speed.drops for more than·.100-rpm; orthe englhe speed is unstable arid flunduates between
500-700 rpm -> The concern is causeq, by carbpn accymulation in the throttle body. Clean the throttle
body according to the following procedure .. · · ·
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The engine speed is stable within the specificatilln ,>-The concern is not caused by carbon accumulation
in the throttle body. Diagnosis for other concerns according to the Workshop Manua!. ·
Chart for making decision of carbon accumulation inJhe throttle body.

700
600
500

RPM

2822.a

A

Engine at idle (warmed-up with no loads)

B

Start of test mode

c

Sample 1: No Good - RPM decreases

D

Sample 2: No Good - RPM is unstable

E

Sample 3: Good - RPM is within spec

Page 3 of 6

Bulletin No: 01-025/13

Last Issued: 08/22/2013

© 2013 Mazda Motor of America, Inc.

7. Open the throttle valve (C) to clean. Spray carbon blaster on a clean soft cloth,and wipe thearea indicated
(A= area to clean).

CAUTION:
DO NOT spray carbon blaster directly on the throttle body valve shaft (B). The rubber part at
the throttle body shaft bearing will be damaged if if is ex\:>osed to the carbon blaster.
Be careful to not pinch your fingers with the throttle valve as it returns by spring force (D).

A

Ill 0

2822d

8. Install the removed parts in the reverse order.

NOTE: Use new gaskets as they cannot be re-used.

PART(S) INFORMATION
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Part Number

Description

Qty.

Notes

L3G2-13-655

Throttle Body Gasket

1

Replacement parts.

0000-77-A86

Engine Cleaner
(Carbon Blaster)

1

Quantity 1 = 1 can of engine cleaner when
ordered through eMDCS.

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