OBD II scan tool (excluding hand-held tester):

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

CHECK WIRE HARNESS (ACCELERATOR PEDAL POSITION SENSOR - ECM)
1. Disconnect the A27 sensor connector.
2. Disconnect the E5 ECM connector.
3. Measure the resistance of the wire harness side connectors.
  
  Fig 1: Identifying Wire Harness Accelerator Pedal Position Sensor & ECM Connector Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard:
  
  Fig 2: Harness Resistance Values
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
2. OK: GO TO NEXT STEP.
INSPECT ECM (VCPA AND VCP2 VOLTAGE)
1. Disconnect the A27 sensor connector.
2. Turn the ignition switch ON.
3. Measure the voltage of the ECM connector.
  
  Fig 3: Inspecting ECM (VCPA And VCP2 Voltage)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard:
  
  Fig 4: Harness Voltage Specifications
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPLACE ECM (See REPLACEMENT )
2. OK: GO TO NEXT STEP.
REPLACE ACCELERATOR PEDAL ROD ASSY (See REPLACEMENT )
1. GO TO NEXT STEP.

READ OUTPUT DTC (ACCELERATOR PEDAL POSITION SENSOR DTCS ARE OUTPUT AGAIN)

Clear the DTC (see DTC CHECK/CLEAR ).
Start the engine.
Run the engine at idle for 15 seconds or more.

Read the DTC.

Result:

DTC OUTPUT RESULT

Display (DTC Output)	Proceed to
P2120, P2122, P2123, P2125, P2127, P2128 and/or P2138 are output again	A
No DTC output	B

B: SYSTEM OK
A: REPLACE ECM (See REPLACEMENT )