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DTC P2123: Accelerator Pedal Position Sensor (main) Circuit High Input
 
 
 
 
CIRCUIT OPERATION
  • A 5-volt power supply is applied on the accelerator pedal position sensor (main) power terminal from the ECM terminal APS5.
  • A voltage that is according to the accelerator opening angle is sent to the ECM terminal APSM from the accelerator pedal position sensor (main) output terminal.
  • The ground terminal is grounded with ECM terminal APSE.
 
 
TECHNICAL DESCRIPTION
  • The accelerator pedal position sensor (main) outputs voltage which corresponds to the accelerator pedal depression.
  • The ECM checks whether the voltage is within a specified range.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • Accelerator pedal position sensor (main) output voltage is out of specified range.
 
 
MONITOR EXECUTION
  • Continuous
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Not applicable
 
 
DTC SET CONDITIONS
Logic Flow Chart
 
 
Check Condition
  • Ignition switch is "ON" position.
Judgment Criterion
  • Accelerator pedal position sensor (main) output voltage should be 4.8 volts or higher for 0.3 second.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • Throttle opening degree is restricted.
  • Throttle opening degree position is in default position if accelerator pedal position sensor (sub) fails.
 
 
OBD-II DRIVE CYCLE PATTERN
  • None.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be stored are: )
  • Accelerator pedal position sensor failed.
  • Open accelerator pedal position sensor (main) circuit, harness damage, or connector damage.
  • ECM failed.

 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle Communication Interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite Main Harness A
  • MB992747: V.C.I.-Lite USB Cable Short
  • MB992748: V.C.I.-Lite USB Cable Long
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: Vehicles Communication Interface (V.C.I.)
    • MB991827: M.U.T.-III USB Cable
    • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
STEP 1. Using scan tool (M.U.T.-III), check data list item 11: Accelerator Pedal Position Sensor (main).
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
(1) Connect scan tool (M.U.T-III). Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) .
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool (M.U.T.-III) to the data reading mode for item 11, Accelerator Pedal Position Sensor (main).
  • Output voltage is between 0.9 and 1.1 volts when foot is released from accelerator pedal.
  • Output voltage is 4.0 volts or higher when accelerator pedal is fully depressed.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
Go to Step 2.
 
STEP 2. Check the continuity at accelerator pedal position sensor harness side connector.
(1) Disconnect the accelerator pedal position sensor connector and measure at the harness side.
(2) Measure the continuity between terminal APSE line and ground.
  • Continuity (2 ohms or less)
Does continuity exist?
Go to Step 5.
Go to Step 3.
 
STEP 3. Check of open circuit and harness damage in APSE line between accelerator pedal position sensor connector and ECM connector.
Is the harness wire in good condition?
Go to Step 4.
Repair it. Then go to Step 6.
 
STEP 4. Using scan tool (M.U.T.-III), check data list item 11: Accelerator Pedal Position Sensor (main).
(1) Turn the ignition switch to the "ON" position.
(2) Set scan tool (M.U.T.-III) to the data reading mode for item 11, Accelerator Pedal Position Sensor (main).
  • Output voltage is between 0.9 and 1.1 volts when foot is released from accelerator pedal.
  • Output voltage is 4.0 volts or higher when accelerator pedal is fully depressed.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
Replace the ECM (Refer to Removal and Installation ). Then go to Step 6.
 
STEP 5. Replace the accelerator pedal position sensor.
(1) Replace the accelerator pedal position sensor.
(2) Turn the ignition switch to the "ON" position.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is DTC P2123 stored?
Replace the ECM (Refer to Removal and Installation ). Then go to Step 6.
The inspection is complete.
 
STEP 6. Using scan tool (M.U.T.-III), read the diagnostic trouble code (DTC).
(1) Turn the ignition switch to the "ON" position.
(2) After the DTC has been deleted, read the DTC again.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Is DTC P2123 stored?
Retry the troubleshooting.
The inspection is complete.