DTC P1708 Throttle Position Sensor Circuit Low Input

WARNING: This page is about a different variant/trim than selected.

DTC DETECTING CONDITION:

The input signal circuit of accelerator pedal position sensor is open or shorted.

TROUBLE SYMPTOM:

Shift point is too high or too low.
Excessive shift shock
Tight corner braking phenomenon is occurred.

WIRING DIAGRAM:

Fig 1: Wiring Diagram - Throttle Position Sensor Circuit (Low Input)

Courtesy of SUBARU OF AMERICA, INC.

DTC P1708 DIAGNOSTIC PROCEDURE

Step	CHECK	Yes	No
1 CHECK ENGINE GROUND TERMINALS.	Have engine ground terminals been tightened securely?	Go to step 2 .	Tighten the engine ground terminals.
2 CHECK GROUND CIRCUIT FOR ECM. Turn the ignition switch to OFF. Disconnect the connector from ECM. Measure the resistance of harness between ECM and engine ground. Connector & terminal (B134) No. 7 - Engine ground: (B134) No. 6 - Engine ground: (B135) No. 1 - Engine ground: (B135) No. 4 - Engine ground: (B135) No. 12 - Engine ground: (B137) No. 1 - Engine ground: (B137) No. 2 - Engine ground: (B137) No. 3 - Engine ground: (B137) No. 7 - Engine ground:	Is the resistance less than 5 Ω?	Go to step 3 .	Repair the open circuit in harness between ECM connector and engine grounding terminal.
3 CHECK ACCELERATOR PEDAL POSITION SENSOR. Disconnect the connectors from accelerator pedal position sensor. Measure the resistance between accelerator pedal position sensor connector receptacle's terminals. Connector & terminal No. 1 - No. 6:	Is the resistance 0.75 - 3.15 kΩ?	Go to step 4 .	Replace the accelerator pedal position sensor.
4 CHECK ACCELERATOR PEDAL POSITION SENSOR. Measure the resistance between accelerator pedal position sensor connector receptacle's terminals. Connector & terminal No. 6 - No. 2:	Is the resistance 0.15 - 0.63 kΩ?	Go to step 5 .	Replace the accelerator pedal position sensor.
5 CHECK HARNESS CONNECTOR BETWEEN TCM AND ACCELERATOR PEDAL POSITION SENSOR. Disconnect the connector from TCM. Measure the resistance of harness between TCM and accelerator pedal position sensor connector. Connector & terminal (B54) No. 19 - (B315) No. 2:	Is the resistance less than 1 Ω?	Go to step 6 .	Repair the open circuit in harness between TCM and accelerator pedal position sensor connector, and poor contact in coupling connector.
6 CHECK HARNESS CONNECTOR BETWEEN TCM AND ACCELERATOR PEDAL POSITION SENSOR. Measure the resistance of harness between TCM connector and chassis ground. Connector & terminal (B54) No. 19 - Chassis ground:	Is the resistance more than 1 MΩ?	Go to step 7 .	Repair the short circuit in harness between TCM and accelerator pedal position sensor connector.
7 CHECK HARNESS CONNECTOR BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR. Remove the connector from ECM. Measure the resistance of harness between the accelerator pedal position sensor connector and chassis ground. Connector & terminal (B315) No. 6 - Chassis ground:	Is the resistance more than 1 MΩ?	Go to step 8 .	Repair the short circuit in harness between ECM and accelerator pedal position sensor.
8 CHECK INPUT SIGNAL FOR TCM USING SUBARU SELECT MONITOR. Connect the connectors to TCM, accelerator pedal position sensor, and ECM. Connect the Subaru Select Monitor to data link connector. Turn the ignition switch to ON (engine OFF). Turn the Subaru Select Monitor switch to ON. Fully close the throttle. Read the data of "Throttle Sensor Voltage" using Subaru Select Monitor. Accelerator pedal position sensor input signal is indicated.	Is the voltage more than 0.2 V?	Even if the SPORT indicator light is blinking, the circuit has returned to normal condition at this time. A temporary poor contact of connector or harness may be the cause. Repair the harness or connector in accelerator pedal position sensor circuit.	Go to step 9 .
9 CHECK POOR CONTACT.	Is there poor contact in accelerator pedal position sensor circuit?	Repair the poor contact.	Replace the TCM. < Ref. to TRANSMISSION CONTROL MODULE (TCM) . >