2004 SUBARU FORESTER check engine

EN(H4DOTC 2.5)-244
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
1) Measure the resistance of accelerator
pedal position sensor.
Te r m i n a l s
No. 2 — No. 6:
2) Check the measured value is within the
specification without depressing the accelera-
tor pedal.Is the resistance 0.15 — 0.63
kΩ?Go to step 8.Replace the accel-
erator pedal posi-
tion sensor.
8 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
1) Measure the resistance of accelerator
pedal position sensor.
Te r m i n a l s
No. 2 — No. 6:
2) Check the measured value is within the
specification with the accelerator pedal
depressed.Is the resistance 0.28 — 1.68
kΩ?Repair the poor
contact in ECM
connector.
Replace the ECM
if defective.Replace the accel-
erator pedal posi-
tion sensor. Step Check Yes No

EN(H4DOTC 2.5)-246
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ACCELERATOR PEDAL POSITION
SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) Read the data of sub accelerator pedal
position sensor signal using Subaru Select
Monitor.
3) Check the voltage change by shaking the
harness and connector of ECM, engine har-
ness connector and accelerator pedal position
sensor connector harness.Is the voltage less than 4.8 V? Go to step 2.Go to step 3.
2 CHECK POOR CONTACT.
Check poor contact in connector between
ECM and accelerator pedal position sensor.Is there poor contact? Repair the poor
contact.Temporary poor
contact occurred,
but it is normal at
present.
3 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connector from the acceler-
ator pedal position sensor.
4) Measure the resistance between ECM con-
nector and accelerator pedal position sensor con-
nector.
Connector & terminal
(B136) No. 35 — (B315) No. 6:Is the resistance less than 1
Ω?Go to step 4.Repair the open
circuit of harness
connector.
4 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Connect the ECM connector.
2) Measure the resistance between accelerator
pedal position sensor connector and engine
ground.
Connector & terminal
(B315) No. 6 — Engine ground:Is the resistance less than 5
Ω?Go to step 5.Repair the poor
contact in ECM
connector.
Replace the ECM
if defective.
5 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between accelerator
pedal position sensor connector and engine
ground.
Connector & terminal
(B315) No. 1 (+) — Engine ground (
−):
4) Check the voltage is above the specified value
when shaking the harness and connector of ECM
while monitoring the value with voltage meter.Is the voltage less than 6 V? Go to step 6.Repair battery short
circuit in harness
between ECM con-
nector and acceler-
ator pedal position
sensor connector.
6 CHECK POWER SUPPLY OF ACCELERA-
TOR PEDAL POSITION SENSOR.
1) Measure the voltage between accelerator
pedal position sensor connector and engine
ground.
Connector & terminal
(B315) No. 2 (+) — Engine ground (
−):
2) Check the voltage change by shaking the
harness and connector of ECM while monitor-
ing the value with voltage meter.Is the voltage less than 4.8 V? Go to step 7.Repair short circuit
in harness between
ECM connector and
accelerator pedal
position sensor con-
nector.

EN(H4DOTC 2.5)-247
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Connect the accelerator pedal position sen-
sor connector.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B136) No. 16 (+) — Chassis ground (
−):Is the voltage 4.8 V? Repair the poor
contact in ECM
connector.
Replace the ECM
if defective.Repair poor con-
tact in accelerator
pedal position sen-
sor connector.
Replace the accel-
erator pedal posi-
tion sensor if
defective. Step Check Yes No

EN(H4DOTC 2.5)-250
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector terminals.
Connector & terminal
(B136) No. 18 (+) — (B136) No. 35 (
−):
3) Check the voltage change by shaking the har-
ness and connector of ECM, engine harness con-
nector and electronic throttle control connector.Is the voltage more than 0.4 V? Go to step 2.Go to step 4.
2 CHECK SENSOR OUTPUT.
1) Measure the voltage between ECM con-
nector terminals.
Connector & terminal
(B136) No. 29 (+) — (B136) No. 35 (
−):
2) Check the voltage change by shaking the har-
ness and connector of ECM, engine harness con-
nector and electronic throttle control connector.Is the voltage more than 0.8 V? Go to step 3.Go to step 4.
3 CHECK POOR CONTACT.
Check the poor contact in connector between
ECM and electronic throttle control.Is there poor contact? Repair the poor
contact.Go to step 14.
4 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connectors from the elec-
tronic throttle control.
4) Measure the resistance between ECM con-
nector and electronic throttle control connector.
Connector & terminal
(B136) No. 16 — (E57) No. 5:Is the resistance less than 1
Ω?Go to step 5.Repair the open
circuit of harness
connector.
5 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B136) No. 16 — Chassis ground:
(B136) No. 18 — Chassis ground:
(B136) No. 29 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 6.Repair the ground
short circuit of har-
ness.
6 CHECK SENSOR POWER SUPPLY.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 5 (+) — Engine ground (
−):
4) Check the voltage change by shaking the
harness and connector of ECM and engine
harness connector while monitoring the value
with voltage meter.Is the voltage 4.5 — 5.5 V? Go to step 7.Repair the poor
contact in ECM
connector.
Replace the ECM
if defective.
7 CHECK SHORT CIRCUIT IN ECM.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 4 — Engine ground:
(E57) No. 6 — Engine ground:Is the resistance more than 10
Ω?Go to step 8.Repair the poor
contact in ECM
connector.
Replace the ECM
if defective.

EN(H4DOTC 2.5)-251
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK SENSOR OUTPUT.
1) Connect all the connectors.
2) Turn the ignition switch to ON.
3) Read the data of main throttle sensor signal
using Subaru Select Monitor.
4) Check the voltage change by shaking the har-
ness and connector of ECM, engine harness con-
nector and electronic throttle control connector.Is the voltage less than 4.63
V?Go to step 9.Go to step 11.
9 CHECK SENSOR OUTPUT.
1) Read the data of sub throttle sensor signal
using Subaru Select Monitor.
2) Check the voltage change by shaking the har-
ness and connector of ECM, engine harness con-
nector and electronic throttle control connector.Is the voltage less than 4.73
V?Go to step 10.Go to step 11.
10 CHECK POOR CONTACT.
Check the poor contact in connector between
ECM and electronic throttle control.Is there poor contact? Repair the poor
contact.Temporary poor
contact occurred,
but it is normal at
present.
11 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connectors from the elec-
tronic throttle control.
4) Measure the resistance between ECM con-
nector and electronic throttle control connector.
Connector & terminal
(B136) No. 18 — (E57) No. 6:
(B136) No. 29 — (E57) No. 4:
(B136) No. 35 — (E57) No. 3:Is the resistance less than 1
Ω?Go to step 12.Repair the open
circuit of harness
connector.
12 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Connect the ECM connector.
2) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 3 — Engine ground:Is the resistance less than 5
Ω?Go to step 13.Repair the poor
contact in ECM con-
nector. Replace the
ECM if defective.
13 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 5 (+) — Engine ground (
−):
4) Check the voltage change by shaking the
harness and connector of ECM and engine
harness connector while monitoring the value
with voltage meter.Is the voltage more than 10 V? Go to step 14.Repair battery short
circuit in harness
between ECM con-
nector and elec-
tronic throttle control
connector. Step Check Yes No

EN(H4DOTC 2.5)-252
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
14 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 4 (+) — Engine ground (
−):
(E57) No. 6 (+) — Engine ground (
−):
2) Check the voltage change by shaking the
harness and connector of ECM and engine
harness connector while monitoring the value
with voltage meter.Is the voltage less than 10 V? Go to step 15.Repair short circuit
in harness between
ECM connector and
electronic throttle
control connector.
15 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the ECM connector.
3) Measure the resistance between ECM con-
nectors.
Connector & terminal
(B136) No. 18 — (B136) No. 35:
(B136) No. 29 — (B136) No. 35:Is the resistance more than 1
MΩ?Go to step 16.Repair short circuit
to sensor power
supply.
16 CHECK ELECTRONIC THROTTLE CON-
TROL HARNESS.
1) Disconnect the connector from ECM.
2) Disconnect the connectors from the elec-
tronic throttle control.
3) Measure the resistance between electronic
throttle control connector terminals.
Connector & terminal
(E57) No. 6 — (E57) No. 4:Is the resistance more than 1
MΩ?Repair the poor
contact in ECM con-
nector. Replace the
ECM if defective.Repair the short
circuit of harness. Step Check Yes No

EN(H4DOTC 2.5)-254
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ACCELERATOR PEDAL POSITION
SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and terminal.
Connector & terminal
(B136) No. 17 (+) — (B136) No. 34 (
−):
(B136) No. 28 (+) — (B136) No. 35 (
−):
3) Check the voltage change by shaking the
harness and connector of ECM and accelera-
tor pedal position sensor connector and har-
ness.Is the voltage more than 0.4 V? Go to step 2.Go to step 3.
2 CHECK POOR CONTACT.
Check poor contact in connector between
ECM and accelerator pedal position sensor.Is there poor contact? Repair the poor
contact.Go to step 12.
3 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connector from the acceler-
ator pedal position sensor.
4) Measure the resistance between ECM con-
nector and accelerator pedal position sensor con-
nector.
Connector & terminal
(B136) No. 15 — (B315) No. 3:
(B136) No. 16 — (B315) No. 1:
(B136) No. 17 — (B315) No. 5:
(B136) No. 28 — (B315) No. 2:Is the resistance less than 1
Ω?Go to step 4.Repair the open
circuit of harness
connector.
4 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B136) No. 15 — Chassis ground:
(B136) No. 16 — Chassis ground:
(B136) No. 17 — Chassis ground:
(B136) No. 28 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair the ground
short circuit of har-
ness.
5 CHECK POWER SUPPLY OF ACCELERA-
TOR PEDAL POSITION SENSOR.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between accelerator
pedal position sensor connector and engine
ground.
Connector & terminal
(B315) No. 3 (+) — Engine ground (
−):
(B315) No. 1 (+) — Engine ground (
−):
4) Check the voltage change by shaking the
harness and connector of ECM while monitor-
ing the value with voltage meter.Is the voltage 4.5 — 5.5 V? Go to step 6.Repair the poor
contact in ECM con-
nector. Replace the
ECM if defective.
6 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor.
Te r m i n a l s
No. 3 — No. 4:Is the resistance 1.2 — 4.8
kΩ?Go to step 7.Replace the accel-
erator pedal posi-
tion sensor.

EN(H4DOTC 2.5)-255
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor.
Te r m i n a l s
No. 1 — No. 6:Is the resistance 0.75 — 3.15
kΩ?Go to step 8.Replace the accel-
erator pedal posi-
tion sensor.
8 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor without depressing the accel-
erator pedal.
Te r m i n a l s
No. 5 — No. 4:Is the resistance 0.2 — 0.8
kΩ?Go to step 9.Replace the accel-
erator pedal posi-
tion sensor.
9 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor without depressing the accel-
erator pedal.
Te r m i n a l s
No. 2 — No. 6:Is the resistance 0.15 — 0.63
kΩ?Go to step 10.Replace the accel-
erator pedal posi-
tion sensor.
10 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor with the accelerator pedal
depressed.
Te r m i n a l s
No. 5 — No. 4:Is the resistance 0.5 — 2.5
kΩ?Go to step 11.Replace the accel-
erator pedal posi-
tion sensor.
11 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor with the accelerator pedal
depressed.
Te r m i n a l s
No. 2 — No. 6:Is the resistance 0.28 — 1.68
kΩ?Go to step 12.Replace the accel-
erator pedal posi-
tion sensor.
12 CHECK ACCELERATOR PEDAL POSITION
SENSOR OUTPUT.
1) Turn the ignition switch to OFF.
2) Connect all the connectors.
3) Turn the ignition switch to ON.
4) Read the data of main throttle sensor signal
and sub accelerator pedal position sensor sig-
nal using Subaru Select Monitor.
5) Check the voltage change by shaking the
harness and connector of ECM, engine har-
ness connector and accelerator pedal position
sensor connector harness.Is the voltage less than 4.8 V? Go to step 13.Go to step 14.
13 CHECK POOR CONTACT.
Check poor contact in connector between
ECM and accelerator pedal position sensor.Is there poor contact? Repair the poor
contact.Go to step 19. Step Check Yes No