DTC P2102: Throttle Actuator "A" Control Motor Circuit Low: Notes

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Improper idling
Poor driving performance
Engine stalls.

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

CHECK ELECTRONIC THROTTLE CONTROL RELAY.
1. Turn the ignition switch to OFF.
2. Remove the electronic throttle control relay.
3. Connect the battery to terminals No. 2 and No. 4 of electronic throttle control relay.
4. Measure the resistance between electronic throttle control relay terminals.
  Terminals.
  
  No. 1 - No. 3:
Is the resistance less than 1 Ω?

Yes : Go to 2.

No : Replace the electronic throttle control relay. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ELECTRONIC THROTTLE CONTROL RELAY .
CHECK POWER SUPPLY OF ELECTRONIC THROTTLE CONTROL RELAY.
Measure the voltage between M/B (electronic throttle control relay) terminal and engine ground.

Terminals.

No. 1 (+) - Engine ground (-):

No. 2 (+) - Engine ground (-):

Is the voltage 10 V or more?

Yes : Go to 3.

No : Repair the following item.
- Open circuit or short circuit to ground in harness between M/B (fuse No. 19) and M/B (electronic throttle control relay) terminal
- Blown out of fuse
CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL RELAY CONNECTOR (SHORT TO POWER SUPPLY).
1. Disconnect the connector from ECM.
2. Turn the ignition switch to ON.
3. Measure the voltage between M/B (electronic throttle control relay) terminal and engine ground.
  Terminals.
  
  No. 4 (+) - Engine ground (-):
Is the voltage 10 V or more?

Yes : Repair the short circuit to power in the harness between ECM connector and M/B (electronic throttle control relay) terminal.

No : Go to 4.
CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL RELAY (SHORT TO GROUND).
1. Turn the ignition switch to OFF.
2. Measure the resistance between M/B (electronic throttle control relay) terminal and engine ground.
  Terminals.
  
  No. 3 - Engine ground:
  
  No. 4 - Engine ground:
Is the resistance 1 MΩ or more?

Yes : Go to 5.

No : Repair the short circuit to ground in the harness between ECM connector and M/B (electronic throttle control relay) terminal.
CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL RELAY (OPEN).
Measure the resistance between ECM connector and M/B (electronic throttle control relay) terminal.

Connector and terminal.

(B134) No. 65 - No. 3:

(B134) No. 36 - No. 4:

Is the resistance less than 1 Ω?

Yes : Repair the poor contact of ECM connector.

No : Repair the open circuit in harness between ECM connector and electronic throttle control relay connector.