Subaru 2009 IMPREZA Service Manual page 921

Diagnostic Trouble Code (DTC) Detecting Criteria
DR:DTC P2138 THROTTLE/PEDAL POSITION SENSOR/SWITCH "D"/"E"
VOLTAGE CORRELATION
1. OUTLINE OF DIAGNOSIS
Judge as NG when the signal level of throttle position sensor 1 is different from the throttle position sensor 2.
2. COMPONENT DESCRIPTION
(1)
(1) Engine control module (ECM)
(2) Accelerator pedal position sensor
1 signal
3. ENABLE CONDITION
Secondary Parameters
Ignition switch
Battery voltage
4. GENERAL DRIVING CYCLE
Always perform the diagnosis continuously.
(2)
(3)
(3) Accelerator pedal position sensor
2 signal
Enable Conditions
ON
6 V
GD(H4SO)-197
GENERAL DESCRIPTION
(4)
(4) Accelerator pedal position sensor
EN-01861