“1”

“2”

“1”

“2”

Is Cam Signal Edge Within Window RH?

Yes

No

Yes

Yes

Is Cam Signal Edge Within Window LH?

Yes

Yes

No

Yes

NOTE: A LH cam position sensor signal does not always indicate a corresponding #2 or #4
cylinder firing. (The same applies to the RH side.)
Using the chart above and comparing it to Example 1, it can be determined the first cylinder
shown in the screen shot is #3 because the crank signal is a “2” and there is an edge signal
within the window on the LH but not the RH cam sensor. Next cylinder in the firing order
would be #2 as the crank position signal is a “1” and there is an edge signal in the window for
the RH but not for the LH, and so on…

continued...
Bulletin Number: 11-130-13R; Date: 06/19/13

Page 4

Example 2 below shows a “Bad” pattern for the RH cam sensor. Marks #1 and #2 show what
appears to be #4 cylinder firing but, the next cylinder to fire according to the screen shot is
#2 followed by #4 then #1. The pattern for the RH sensor never shows the proper sequence
to fire #3 cylinder. In this case, recheck the data again after installing a .2mm shim under the
RH cam sensor.
Proper Firing Order is:

#3

#2

#4

#1

#3

#2

Firing Order shown in screen shot:

#4

#2

#4

#1

#4

#2

Erratic Cam Sensor Signals
“EXAMPLE 2”

continued...
Bulletin Number: 11-130-13R; Date: 06/19/13

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Example 3 shows what appears to be an erratic signal from the RH cam sensor but, you can
see all the cam sensor data signal edges (drops) follow the chart and firing order as they are
supposed to. Other signal edges (rises or drops) outside the “window” or a longer time line
as shown here prior to the #4 signal edges seen on the RH cam sensor pattern are examples of
signals which will be “ignored” by the ECM and are not a cause for concern.
#4

#1

#3

Normal Cam Sensor Signals

#2

#4

Rise outside of “Window”

“EXAMPLE 3”

continued...
Bulletin Number: 11-130-13R; Date: 06/19/13

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IMPORTANT: If you confirm an irregular wave form pattern, BEFORE performing the
measurement and shim selection procedures, install a .2mm shim under the suspect intake or
exhaust camshaft position sensor. If there is no change, remove the .2mm shim and install a
.4mm shim. USE ONLY ONE SHIM PER SENSOR, NO STACKING. If the wave pattern
is lost, remove the .4mm shim and replace with a .3mm shim. Recheck the pattern and if it
appears normal, complete the repair as shown below. If an abnormal pattern persists, proceed
with the rest of the clearance measurement and shim selection procedures.
a.
b.
c.
d.
e.

Install a NEW camshaft position sensor o-ring (one-time use item).
Reinstall the camshaft position sensor and shim.
Torque the sensor retaining bolt to 6.4 Nm (4.7 ft. lbs. or 56.4 inch-pounds).
Reconnect the sensor engine wiring harness connector.
Reconnect the negative battery cable then reset the radio station presets (and
navigation system favorites if applicable) to complete the repair.

If an abnormal oscilloscope pattern persists for an intake sensor, measure the clearance
between the end of the camshaft position sensor and the sensor plate using the following
procedure. If a suspect pattern is verified for an exhaust sensor, a revised procedure will be
outlined later in this Bulletin. If the pattern is normal, refer to the applicable Service Manual
for additional troubleshooting and diagnostic procedures for the stored DTCs.

MEASUREMENT AND SHIM SELECTION PROCEDURES
The specified clearance is 1.3 +/- .05mm (1.25 to 1.35mm or .049” to .053”).
1. Record the customer’s radio station presets (and navigation system favorites if applicable).
2. Disconnect the negative battery cable.
3. Remove the camshaft position sensor from the timing chain cover using the procedure in
the applicable Service Manual.

T = 6.4 N•m
(0.7 kgf-m, 4.7 ft-lb)

Camshaft Sensor

Timing Chain Cover

Shim (to be added)

continued...
Bulletin Number: 11-130-13R; Date: 06/19/13

Page 7

A = Top of timing chain cover to camshaft position sensor plate
B = Camshaft position sensor mating surface to the bottom of the sensor

B

A

Camshaft position
sensor plate.

NOTE: When measuring “A”, make sure you are measuring to the outside diameter or “top”
of the sensor plate and not to the bottom of a notch as shown below. Be sure to record all
measurements.

Top of Plate

Notch

continued...
Bulletin Number: 11-130-13R; Date: 06/19/13

Page 8

Measurement taken using digital
caliper with depth attachment.

Measurement taken using digital
caliper with washer.

IMPORTANT: When using the flat washer, make sure the washer is fully seated on the
machined surfaces of the timing cover or your measurements will not be accurate.
1. Take a measurement and record the reading.
2. Using a breaker bar and 22mm socket, place the socket on the crankshaft pulley bolt and
rotate the engine clockwise approximately 70°. CAUTION: Do not rotate the engine
counter-clockwise, doing so will loosen the crankshaft pulley bolt. If the engine is
accidently turned counter-clockwise make sure the bolt is re-torqued following the proper
procedure in the applicable Service Manual.
3. Take a measurement and record the reading.
4. Rotate the engine clockwise approximately 70°.
5. Take a measurement and record the reading.
6. Use the smallest of the three measurements and record the result.

continued...
Bulletin Number: 11-130-13R; Date: 06/19/13

Page 9

When taking measurement “B”, use a flat steel ruler or equivalent along with the digital
caliper.

7. Measure the distance between the camshaft position sensor mounting surface and the
bottom of the sensor as shown above.
IMPORTANT: Be sure to account for the thickness of the flat washer (if you are using one)
when performing your calculations to determine the required shim thickness.
The specified clearance is 1.3 +/- .05mm (1.25 to 1.35mm or .049” to .053”).
Example calculation
(the 1.72mm thickness of the flat washer is subtracted from “A” dimension)
A = Top of timing chain cover to camshaft position sensor plate
B = Camshaft position sensor mating surface to the bottom of the sensor
A) 25.42 – 1.72 = 23.70
A = 23.70
B = 22.58
A – B = 1.12 (clearance)
In this example a 0.2 shim is required.
Clearance (mm)
1.06 – 1.15

Shim Thickness (mm)
0.2

Target Gap (mm)
1.26 – 1.35

continued...
Bulletin Number: 11-130-13R; Date: 06/19/13

Page 10

8. After the correct shim is selected and a normal oscilloscope pattern has been
verified:
a. Install a NEW camshaft position sensor o-ring (one-time use item).
b. Reinstall the camshaft position sensor and shim.
c. Torque the sensor retaining bolt to 6.4 Nm (4.7 ft. lbs. or 56.4 inch-pounds).
d. Reconnect the sensor engine wiring harness connector.
e. Reconnect the negative battery cable then reset the radio station presets (and
navigation system favorites if applicable) to complete the repair.
BRZ EXHAUST CAMSHAFT POSITION SENSOR PROCEDURE
In the event you have a DTC stored for an exhaust camshaft position sensor, the repair
procedure has been revised. Due to the position of the right-hand (Bank 1) sensor,
measurement of the gap without removing the front catalyst is extremely difficult as shown in
the photo below.

Cam Position
Sensor Harness
Connector

In addition, the engine under-guards must be removed along with the plastic splash shield
to access the left-hand (Bank 2) sensor. As a solution, the following procedure has been
developed:
1. Confirm the irregular oscilloscope pattern for the corresponding DTC stored.
2. Remove the sensor from the timing cover and install a .2mm thick shim from the
applicable kit.
3. Reinstall the sensor, torque the sensor retaining bolt to 6.4 Nm
(4.7 ft. lbs. or 56.4 inch-pounds) then recheck the oscilloscope pattern.
continued...
Bulletin Number: 11-130-13R; Date: 06/19/13

Page 11

If the pattern is normal, the repair is complete. If the irregular pattern persists, repeat Steps 2
and 3 after removing the .2mm shim and installing a .3 mm thick shim. ONE SHIM ONLY,
NO STACKING. Repeat as necessary increasing the shim thickness .1 mm at a time until a
normal scope pattern can be verified.

4. After the correct shim is selected:
a.
b.
c.
d.
e.

Install a new camshaft position sensor o-ring (one-time use item).
Reinstall the camshaft position sensor and shim.
Torque the sensor retaining bolt to 6.4 Nm (4.7 ft. lbs. or 56.4 inch-pounds).
Reconnect the sensor engine wiring harness connector.
Reconnect the negative battery cable and reset the radio station presets (and
navigation system favorites if applicable) to complete the repair.

5. Be sure to clear the ECM memory before returning the vehicle to the customer.

WARRANTY/CLAIM INFORMATION
For vehicles within the Basic New Car Limited Warranty period, this repair may be claimed
using the following information:
NOTE: Operation Number A817-213 is only applicable to 2.0L Impreza, XV Crosstrek, BRZ
and 2014 Forester Turbo models (models equipped with exhaust AVCS).
Labor Description
Intake Cam Sensor Measurement
and Shim Installation
Exhaust Cam Sensor Measurement
and Shim Installation

Bulletin Number: 11-130-13R; Date: 06/19/13

Labor Operation#

Fail Code

A817-211

Labor Time
0.5

UKM-20
A817-213

0.6

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