Subaru Forester 2004 Service Manual page 173

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTIC)
Step
1 CHECK INPUT VOLTAGE OF ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and ground.
Connector & terminal
(B135) No. 5 (+) — Chassis ground (
(B135) No. 6 (+) — Chassis ground (
2 CHECK INPUT VOLTAGE OF ECM.
1) Start the engine.
2) Measure the voltage between ECM con-
nector and ground.
Connector & terminal
(B135) No. 5 (+) — Chassis ground (
(B135) No. 6 (+) — Chassis ground (
3 CHECK ECM GROUND HARNESS.
Measure the voltage between ECM connector
and ground.
Connector & terminal
(B137) No. 1 (+) — Chassis ground (
(B137) No. 2 (+) — Chassis ground (
AT:DTC P0638 THROTTLE ACTUATOR CONTROL RANGE/PERFORMANCE
(BANK 1)
NOTE:
For diagnostic procedure, refer to DTC P2101. <Ref. to EN(H4DOTC 2.5)-224, DTC P2101 THROTTLE AC-
TUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
Check
Is the voltage 10 — 13 V?
−
):
−
):
Is the voltage 13 — 15 V?
−
):
−
):
Is the voltage less than 1 V?
−
):
−
):
EN(H4DOTC 2.5)-172
Yes
Go to step 2. Repair open or
ground short cir-
cuit of power sup-
ply circuit.
Go to step 3. Repair open or
ground short cir-
cuit of power sup-
ply circuit.
Repair the poor Further tighten the
contact in ECM engine ground ter-
connector. minal.
Replace the ECM
if defective.
No