Subaru legacy 2004 Service Manual page 178

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
• KA and KS model
NOTE:
Fuel injection system for KA and KS model is the same as 2.0 L model. Refer to EN(H4SO 2.0) section.
Step
1 CHECK OPTION CODE.
2 CHECK SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) Read the data of main throttle sensor signal
using Subaru Select Monitor.
3 CHECK SENSOR OUTPUT.
Read the data of sub throttle sensor signal
using Subaru Select Monitor.
4 CHECK POOR CONTACT.
Check poor contact in connector between
ECM and electronic throttle control.
5 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. 16 — (E57) No. 5:
6 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B136) No. 18 — Chassis ground:
(B136) No. 29 — Chassis ground:
(B136) No. 16 — Chassis ground:
7 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 (
Check
Is the option code EC, EK or
K4?
Is the voltage more than 0.4 V? Go to step 3.
Is the voltage more than 0.8 V? Go to step 4.
Is there poor contact?
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is the voltage 4.5 — 5.5 V?
−
):
EN(H4SO 2.5)(diag)-254
Yes
Go to step 2. Refer to EN(H4SO
2.0) section. <Ref.
to EN(H4SO
2.0)(diag)-66, List
of Diagnostic Trou-
ble Code (DTC).>
NOTE:
Fuel injection sys-
tem for KA and KS
model is the same
as 2.0 L model.
Go to step 5.
Go to step 5.
Repair the poor Go to step 15.
contact.
Go to step 6. Repair the open
circuit of harness
connector.
Go to step 7. Repair the ground
short circuit of har-
ness.
Go to step 8. Repair the poor
contact in ECM
connector.
Replace the ECM
if defective. <Ref.
to FU(H4SO 2.5)-
36, Engine Con-
trol Module
(ECM).>
No