Code No. P2122: Accelerator Pedal Position Sensor (main) Circuit Low Input
OPERATION
- A power voltage of 5 V is applied to the accelerator pedal position sensor connector terminal from the engine-ECU connector terminal APS5.
- The power voltage is earthed to the engine-ECU connector terminal APSE from the accelerator pedal position sensor connector terminal.
- The sensor signal is inputted to the engine-ECU connector terminal APSM from the accelerator pedal position sensor output terminal.
FUNCTION
- The accelerator pedal position sensor converts the opening degree of the accelerator pedal into the voltage signal to input it to the engine ECU.
- The engine ECU uses this signal to determine the amount of basic fuel injection.
TROUBLE JUDGEMENT
Check Conditions
- Ignition switch is in "ON" position
- Accelerator pedal position sensor (sub) is normal
Judgement Criterion
- Accelerator pedal position sensor (main) output voltage is lower than 0.2 V.
FAIL-SAFE AND BACKUP FUNCTION
- The amount of depression of the accelerator pedal is detected, using the accelerator pedal position sensor (sub) signal, which is calculated by taking half of the normal value.
PROBABLE CAUSES
- Failed accelerator pedal position sensor
- Open/short circuit or harness damage in accelerator pedal position sensor circuit or loose connector contact
- Failed engine-ECU
|
|
STEP 1. M.U.T.-III data list
|
|
|
- Refer to Data List Reference Table
 .
- Item 9: Accelerator pedal position sensor (main)
|
|
|
Q.
Is the check result normal?
|
|
|
 Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
|
|
|
|
|
|
 Go to Step 2.
|
|
|
|
|
|
STEP 2. Voltage measurement at accelerator pedal position sensor connector (APS5 line).
|
|
|
(1)Disconnect the connector, and measure at the wiring harness side.
|
|
|
(3)Check the voltage between the accelerator pedal position sensor connector (APS5 line) and body earth.
OK: 4.9 - 5.1 V
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 5.
|
|
|
|
|
|
Go to Step 3.
|
|
|
|
|
|
STEP 3. Check of open circuit and short to earth in APS5 line between engine-ECU connector and accelerator pedal position sensor connector.
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 4.
|
|
|
|
|
|
Repair the connector(s) or wiring harness.
|
|
|
|
|
|
STEP 4. M.U.T.-III data list
|
|
|
- Refer to Data List Reference Table .
- Item 9: Accelerator pedal position sensor (main)
|
|
|
Q.
Is the check result normal?
|
|
|
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
|
|
|
|
|
|
Replace the engine-ECU.
|
|
|
|
|
|
STEP 5. Resistance measurement at accelerator pedal position sensor connector (APSE line).
|
|
|
(1)Disconnect the connector, and measure at the wiring harness side.
|
|
|
(2)Measure the resistance between the accelerator pedal position sensor connector (APSE line) and body earth.
OK: Continuity (2 Ω or less)
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 7.
|
|
|
|
|
|
Go to Step 6.
|
|
|
|
|
|
STEP 6. Check of open circuit and damage in APSE line between accelerator pedal position sensor connector and engine-ECU connector.
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 4.
|
|
|
|
|
|
Repair the connector(s) or wiring harness.
|
|
|
|
|
|
STEP 7. Voltage measurement at accelerator pedal position sensor connector (APSM line).
|
|
|
(1)Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness.
|
|
|
(3)Check the voltage between the accelerator pedal position sensor connector (APSM line) and body earth.
OK: 0.7 - 1.3 V
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 10.
|
|
|
|
|
|
Go to Step 8.
|
|
|
|
|
|
STEP 8. Check of short to earth in APSM line between accelerator pedal position sensor connector and engine-ECU connector.
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 9.
|
|
|
|
|
|
Repair the connector(s) or wiring harness.
|
|
|
|
|
|
STEP 9. Check of damage in APS5 line between engine-ECU connector and accelerator pedal position sensor connector.
|
|
|
Q.
Is the check result normal?
|
|
|
Replace the accelerator pedal assembly.
|
|
|
|
|
|
Repair the connector(s) or wiring harness.
|
|
|
|
|
|
STEP 10. Check of damage in APSM line between accelerator pedal position sensor connector and engine-ECU connector.
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 4.
|
|
|
|
|
|
Repair the connector(s) or wiring harness.
|
|
|
|