16-102-16

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SERVICE MANAGER
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SERVICE BULLETIN
APPLICABILITY: All Models Equipped with CVT Transmissions
SUBJECT: DTC P0841 Diagnostics
NUMBER: 16-102-16
DATE: 07/11/16
INTRODUCTION:
This Service Information bulletin provides a new flow chart and additional diagnostic tools to
assist Technicians with troubleshooting DTC P0841- SECONDARY OIL PRESSURE SENSOR
PERFORMANCE.
SERVICE PROCEDURE / INFORMATION:
The Diagnostic Flow Chart provided in this bulletin is quite extensive. To help make the chart more userfriendly, it has been broken down into 7 basic “Steps”.
IMPORTANT NOTE: In some cases, it may not necessary to follow this flow chart in the specified
order. For example: in a case where a whining sound concern is identified along with the DTC P0841, a
Technician may feel performing pressure checks before beginning the electrical checks may be a way to
expedite diagnosis of an internal hard part failure requiring transmission assembly replacement.
•
•
•
•
•
•
•
STEP 1- CVTF Fluid Condition Check
STEP 2- Customer Interview and DTC Confirmation
STEPS 3A and 3B- Check for Failure Caused by Electrical Wiring / Connection Issues
STEP 4- Check for Abnormal (Stuck) Sensor Output (Cannot Be Detected by Simply Switching
Power ON)
STEP 5- Check the T/M Pressures Stored in the FFD
STEP 6- Determination of Appropriate Repair
STEP 7- Confirmation of Repair
Use this Legend to help navigate the flow chart:
Continued...
Bulletin Number: 16-102-16; Date: 07/11/16
Page 1
DTC P0841- SECONDARY OIL PRESSURE SENSOR PERFORMANCE
DIAGNOSTIC FLOW CHART
STEPS 1 & 2:
START
Step 1- CVTF
Condition Check
Before proceeding, check color and
smell (burnt?) and for contamination
of CVTF to better assess condition of
internal components.
Replace T/M
Assy.
OK
Step 2- Customer
Interview and DTC
Confirmation
NG
Interview the customer
using an interview form from
the Service Manual.
Confirm whether P0841 is stored
as a "Current" or "Past" DTC.
Save any stored FFD
(Freeze Frame Data).
Yes
Besides P0841, are any other
DTCs stored (P0842, P0843,
P0962 or P0963)?
Perform diagnosis of DTCs
other than P0841.
Conduct DRIVING CHECK
North America: Perform DRIVE CYCLE D*
*NOTE: Refer to Service Manual for all Drive
Cycle procedures and details.
AA
No
Did P0841
reset?
No
Yes
BB
To Step 7
Continued...
Bulletin Number: 16-102-16; Date: 07/11/16
Page 2
STEP 3A:
BB
Check the Secondary Oil Pressure
Sensor voltage value using SSM,
with the ign ON, engine OFF.
Standard: 0.39～0.61(V), without
abnormal fluctuation.
（From this point on, every check
should be conducted with and
without wiggling the harness and /
or related connectors).
•Is the voltage within
specification?
3A
Steps 3A & 3B- Check for Failure Caused by
Electrical Wiring / Connection Issues
NOTE: The wiring chart and connectors shown here are applicable to
2016MY Legacy/Outback, North American specification.
Refer to applicable Service Manual for more details / information..
Disconnect the Secondary Oil Pressure Sensor
connector [AT6], and TCU connector [T10]. Check
the harness continuity using a DVOM:
Measure Resistance Between:
These are the checks for a
suspected harness
problem between the TCU
and Secondary Oil
Pressure Sensor.
[T10-Pin33]～[AT6-Pin1]
[T10-Pin5]～[AT6-Pin2]
[T10-Pin2]～[AT6-Pin3]
LESS THAN 1Ω
No
[T10-Pin33]～[T10-Pin5]
[T10-Pin5]～[T10-Pin2]
[T10-Pin2]～[T10-Pin33]
MORE THAN 1MΩ
Yes
This is a check of the 5V
power supply circuit to
the Secondary Oil
Pressure Sensor on the
TCU side.
[T10-Pin33]～T/M case (GND)
[T10-Pin5]～T/M case (GND)
[T10-Pin2]～T/M case (GND)
MORE THAN 1MΩ
Do the results show any
harness problem?
Connect "CHECK BOARD" (18460AA040) to TCU connector [T10].
Turn IG to ON, measure the Secondary Oil Pressure Sensor power
supply voltage on [T10-Pin33～Pin2] using a DVOM with the
Secondary Oil Pressure Sensor connector [AT6] disconnected.
Standard: 4.6～5.4(V) without abnormal fluctuation.
No
Yes
Wiring harness
has problem.
No
Is the sensor's power
supply voltage normal?
Yes
Problem in TCU 5V
power supply circuit.
BB
CC
DD
EE
Continued...
Bulletin Number: 16-102-16; Date: 07/11/16
Page 3
STEP 3B:
BB
DD
CC
This is a check of
the internal circuit
of the Secondary
Oil Pressure Sensor.
3B
EE
Connect the Secondary Oil Pressure Sensor
connector [AT6] and "CHECK BOARD"
(18460AA040) to TCU connector [T10] with IG
ON. Measure the Secondary Oil Pressure Sensor
power supply voltage on [T10-Pin33～Pin2]
using a DVOM.
Standard: 4.6～5.4(V) without abnormal
fluctuation.
Is the sensor's power
supply voltage
normal?
Yes
Perform this check if the any
connector terminals are excessively
opened or loose
(May not be found during continuity
checks).
With the "CHECK BOARD" (18460AA040) connected
to TCU connector [T10] and the Secondary Oil
Pressure Sensor connector [AT6], disconnected, turn
IG to ON, and measure the Secondary Oil Pressure
Sensor power supply voltage at [T10-Pin 5～Pin 2]
using a DVOM. Standard: 0.39～0.61(V) without
abnormal fluctuation.
No
Suspect Oil Pressure
Sensor shorted internally.
Yes
It is suspected the TCU sensor
signal input circuit has
malfunction.
Reason: The Secondary Oil
Pressure Sensor output voltage
is within the normal range but
the sensor input voltage value
is not.
Is the sensor's power
supply voltage
normal?
No
Check the terminals of the
Secondary Oil Pressure Sensor
connector [AT6] or [T10]
（Inspction point: Connector
deformation, damage, or
distortion).
Isolate location of
harness problem.
Suspect poor contact due
to loose pin fit of
connector terminal.
Harness needs repair
or replacement.
Replace TCU.
Replace Oil
Pressure Sensor.
Isolate location of
harness problem.
Replace T/M
wiring harness.
Perform troubleshooting of
P0841 again to confirm the
problem is repaired.
Yes
Is there any
abnormality with
connector [AT6] or
[T10]？
No
Suspected malfunction of the
Secondary Oil Pressure Sensor and
/ or Oil Pressure Sensor circuit.
*No electrical malfunction is
detected.
BB
Continued...
Bulletin Number: 16-102-16; Date: 07/11/16
Page 4
STEP 4:
BB
Step 4- Check for Abnormal
(Stuck) Sensor Output (Cannot
Be Detected By Simply
Switching Power ON)
Check the CVT fluid level in preparation
for Secondary Pressure check.
No
Is fluid level full?
Adjust the fluid level to within
specifications.
Yes
Clear Memory if any DTC is stored.
Test A- Check the Secondary Oil Pressure with the engine idling.
Warm up the CVTF to 60℃, turn IG to OFF then perform
road test for DRIVE CYCLE A*.
*NOTE: Refer to Service Manual for all Drive Cycle procedures and
details.
After that, check and record the actual secondary pressure
in P range with the engine idling using SSM.
Standard: 0.5MPa～1.5MPa, without abnormal fluctuation.
Test B- Check the Secondary Oil Pressure value with the
following conditions:
Warm-up the CVTF to around 60℃, turn IG OFF, then perform
road test for DRIVE CYCLE A* again.
After that, check & record the actual secondary pressure in P
range at 3,000 rpm using SSM. Standard: 1.5MPa～2.5MPa,
without abnormal fluctuation.
Is difference between
Test A & Test B within
0.2MPa.?
No
BB
These (Tests A & B)
are for identifying a
stuck Secondary
Pressure sensor
output.
Suspect malfunction of
Secondary Oil Pressure
Sensor.
Yes
Replace Oil
Pressure Sensor.
Perform troubleshooting of
P0841 again to confirm the
problem is repaired.
Continued...
Bulletin Number: 16-102-16; Date: 07/11/16
Page 5
STEPS 5 & 6:
BB
Step 5- Check the
T/M Fluid Pressures
Stored In the FFD
Check the FFD recorded.
（Refer to "How to identify the symptom
causing P0841" in this TSB.)
Yes
BB
Has previous repair of the wiring or Sensor
replacement been performed?
No
Yes
Does FFD recorded and / or mechanical
gauge readings show low pressure failure?
DD
No
CC
CC
Clear Memory if any DTC is stored
This is the test for a high pressure
sticking malfunction of the
presure adjustment circuit.
Perform a stall test.
Warm up the CVTF to 60℃ then perform
stall test. Confirm and record the actual
Secondary Pressure.
Standard: 4.5～6MPa
Is actual Secondary
Pressure within
specification?
Yes
No
Step 6Determination of
Appropriate Repair
DD
This is the test for a
high pressure
malfunction.
Is pressure below
minimum standard
value?
Yes
No
Suspect oil pressure detection
malfunction due to temporary pressure
adjustment malfunction, or poor
electrical contact.
The pressure adjustment control keeps
Secondary pressure high. In this case,
the variator (pulley set) should not be
damaged by chain slippage.
Replace T/M ASSY.
Replace Control
Valve ASSY.
Suspect control valve assy.
malfunction AND variator
(pulley set) damage due to
the instability of pressure
adjustment.
Replace T/M ASSY.
BB
Continued...
Bulletin Number: 16-102-16; Date: 07/11/16
Page 6
STEP 7:
BB
From AA
in Step 2
Currently normal
condition.
P0841 is suspected
to be stored along
with other DTCs /
problems.
Any replacement of TCU, Control valve assy,
T/M assy, T/M harness, or Secondary Oil
Pressure sensor?
No
Road test vehicle and perform
DRIVE CYCLE D
*Refer to Service Manual for more details.
Is P0841 still detected?
No
Currently normal condition
END
•
BB
Step 7- Confirmation
of Repair
Step 7
o
Any replacementYes
of TCU, Control valve assy,
T/M assy, T/M harness, or Secondary Oil
Pressure sensor?
Y
No
Perform T/M Learning
Procedure.
Road test vehicle and perform
DRIVE CYCLE D
*Refer to Service Manual for more details.
Yes
Currently
abnormal
Is P0841 still
detected?
Perform T/M
Proced
Yes
No
Perform each check of
P0841normal
diagnostics
again.
Currently
condition
END
In addition to the flow chart, use the following slides and information for additional help with
accurately diagnosing a P0841:
TIP: Consider performing the pressure testing using a mechanical pressure gauge BEFORE
electrical testing and compare the test results (between the gauge and SM4 displayed values). Both
test results should be very close. If there is a significant discrepancy between them (e.g. the (known
good) gauge results are significantly higher than the SM4-supplied values), the pressure sensor would
be suspect.
Continued...
Bulletin Number: 16-102-16; Date: 07/11/16
Page 7
Per
P084
Additional Electrical Testing Information:
•
The following slides provide some additional pressure sensor and related wiring testing
techniques, illustrations and photos. This information is intended to help Technicians make a
more informed diagnosis of the root cause and required repairs. It will also help determine
whether or not a terminal /pin connection is damaged and in need of repair or replacement:
Precautions for Checking Transmission / Sensor Wiring:
P0841 Wiring Check Points:
Continued...
Bulletin Number: 16-102-16; Date: 07/11/16
Page 8
Effects of Vibration on Connectors / Terminals:
“Wiggle-Testing” Wiring:
Continued...
Bulletin Number: 16-102-16; Date: 07/11/16
Page 9
Check the Secondary Oil Pressure Sensor:
Other Points to Inspect:
Continued...
Bulletin Number: 16-102-16; Date: 07/11/16
Page 10
Sliding Resistance Testing:
Example of a Deformed Pin Terminal:
Continued...
Bulletin Number: 16-102-16; Date: 07/11/16
Page 11
Example of Incorrect Judgement of a Damaged or
Deformed Pin Terminal:
IMPORTANT REMINDERS:
•
•
•
SOA strongly discourages the printing and/or local storage of service information as previously
released information and electronic publications may be updated at any time.
Always check for any open recalls or campaigns anytime a vehicle is in for servicing.
Always refer to STIS for the latest service information before performing any repairs.
CAUTION: VEHICLE SERVICING PERFORMED BY UNTRAINED PERSONS COULD
RESULT IN SERIOUS INJURY TO THOSE PERSONS OR TO OTHERS.
Subaru Service Bulletins are intended for use by professional technicians ONLY. They
are written to inform those technicians of conditions that may occur in some vehicles,
or to provide information that could assist in the proper servicing of the vehicle. Properly
trained technicians have the equipment, tools, safety instructions, and know-how to
do the job correctly and safely. If a condition is described, DO NOT assume that this
Service Bulletin applies to your vehicle, or that your vehicle will have that condition.
Bulletin Number: 16-102-16; Date: 07/11/16
SUBARU OF AMERICA, INC. IS
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