Code No. P2138: Accelerator Pedal Position Sensor (Main and Sub) Range/Performance Problem
OPERATION
- Refer to Code No. P2122: Accelerator Pedal Position Sensor (main) Circuit Low Input
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- Refer to Code No. P2127: Accelerator Pedal Position Sensor (sub) Circuit Low Input .
FUNCTION
- Engine-ECU checks the accelerator pedal position sensor output signal characteristics for abnormal conditions.
TROUBLE JUDGEMENT
Check Condition
- Ignition switch is in "ON" position.
Judgement Criterion
- When an error is detected on the High side of the accelerator pedal position (main), the accelerator pedal position sensor (sub) is faulty on the High/Low side.
Check Conditions
- Battery positive voltage is 8 - 16 V
- 2 seconds later after the ignition switch has been in "ON" position or the engine has started up
- Engine speed is 600 r/min or more.
- Accelerator pedal position sensor (main) output voltage is 0.2 V or higher and 4.8 V or lower.
- Accelerator pedal position sensor (sub) output voltage is 0.125 V or higher and 2.375 V or lower.
Judgement Criterion
- When a change in the accelerator pedal position sensor (sub) output voltage is less than the specified value, the difference between the opening indicated by the accelerator pedal position sensor (main) and that by the accelerator pedal position sensor (sub) is 20 % or more of the specified value.
FAIL-SAFE AND BACKUP FUNCTION
- The accelerator pedal opening is controlled to be 0 %.
- The idle speed is 1,300 r/min (both of the main and substitute APSs are failed or their characteristics are abnormal).
PROBABLE CAUSES
- Failed accelerator pedal position sensor
- Harness damage in accelerator pedal position sensor circuit or loose connector contact
- Failed engine-ECU
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STEP 1. Resistance measurement at accelerator pedal position sensor connector (APSE line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the resistance between the accelerator pedal position sensor connector (APSE line) and body earth.
OK: Continuity (2 Ω or less)
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Q.
Is the check result normal?
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 Go to Step 2.
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Repair APSE line between engine-ECU connector and accelerator pedal position sensor connector.
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STEP 2. Resistance measurement at accelerator pedal position sensor connector (APE line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the resistance between the accelerator pedal position sensor connector (APE line) and body earth.
OK: Continuity (2 Ω or less)
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Q.
Is the check result normal?
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Go to Step 3.
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Repair APE line between engine-ECU connector and accelerator pedal position sensor connector.
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STEP 3. Voltage measurement at accelerator pedal position sensor connector (APS5 line).
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(1)Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness.
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(3)Check the voltage between the accelerator pedal position sensor connector (APS5 line) and body earth.
OK: 4.9 - 5.1 V
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Q.
Is the check result normal?
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Go to Step 4.
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Repair APS5 line between engine-ECU connector and accelerator pedal position sensor connector.
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STEP 4. Voltage measurement at accelerator pedal position sensor connector (AP5 line).
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(1)Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness.
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(3)Check the voltage between the accelerator pedal position sensor connector (AP5 line) and body earth.
OK: 4.9 - 5.1 V
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Q.
Is the check result normal?
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Go to Step 5.
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Repair AP5 line between engine-ECU connector and accelerator pedal position sensor connector.
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STEP 5. Voltage measurement at engine-ECU connector (APSM terminal).
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(1)Disconnect engine-ECU harness, and connect special tool power plant ECU check harness (MB992291) to measure at connector for inspection.
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(3)Check the voltage between the engine-ECU connector (APSM terminal) and body earth.
OK: 0.7 - 1.3 V
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Q.
Is the check result normal?
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Go to Step 7.
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Go to Step 6.
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STEP 6. Check of damage in APSM line between accelerator pedal position sensor connector and engine-ECU connector.
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Q.
Is the check result normal?
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Replace the accelerator pedal assembly.
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Repair the connector(s) or wiring harness.
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STEP 7. Voltage measurement at engine-ECU connector (APSS terminal).
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(1)Disconnect engine-ECU harness, and connect special tool power plant ECU check harness (MB992291) to measure at connector for inspection.
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(3)Check the voltage between the engine-ECU connector (APSS terminal) and body earth.
OK: 0.2 - 0.8 V
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Q.
Is the check result normal?
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Go to Step 9.
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Go to Step 8.
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STEP 8. Check of damage in APSS line between accelerator pedal position sensor connector and engine-ECU connector.
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Q.
Is the check result normal?
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Replace the accelerator pedal assembly.
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Repair the connector(s) or wiring harness.
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STEP 9. M.U.T.-III diagnosis code
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- Reconfirmation of diagnosis code.
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Q.
Is the check result normal?
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Replace the engine-ECU.
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
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