Code No. P0122: Throttle Position Sensor (Main) Circuit Low Input
OPERATION
- A power voltage of 5 V is applied to the electronic-controlled
throttle valve (terminal No. 2) from the engine-A/T-ECU (terminal No. 106).
- The power voltage is earthed to the engine-A/T-ECU (terminal No. 105) from the electronic-controlled
throttle valve (terminal No. 4).
- The sensor signal is inputted to the engine-A/T-ECU (terminal No. 115) from the
electronic-controlled throttle valve output terminal (terminal No. 1).
FUNCTION
- The throttle position sensor converts the throttle valve
position into voltage and inputs it into the engine-A/T-ECU.
- The engine-A/T-ECU controls the throttle valve position.
TROUBLE JUDGMENT
Check Condition
- Ignition switch is in "ON" position.
- Throttle position sensor (main) output voltage is less than 0.35 V.
PROBABLE CAUSES
- Failed throttle position sensor (main)
- Open/short circuit in throttle position sensor circuit or loose connector contact
- Failed engine-A/T-ECU
DIAGNOSIS PROCEDURE |
STEP 1. M.U.T.-III data list |
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Q.
Is the check result normal?
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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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Go to Step 2 . |
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STEP 2. Connector check: B-31 electronic-controlled throttle valve connector |
Q.
Is the check result normal?
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Go to Step 3 . |
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Repair or replace the connector. |
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STEP 3. Perform voltage measurement at B-31 electronic-controlled throttle valve connector. |
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OK: 4.9 -
5.1 V |
Q.
Is the check result normal?
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Go to Step 7 . |
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Go to Step 4 . |
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STEP 4. Connector check: D-217 engine-A/T-ECU connector |
Q.
Is the check result normal?
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Go to Step 5 . |
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Repair or replace the connector. |
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STEP 5. Check harness between B-31 (terminal No. 2) electronic-controlled throttle valve connector and D-217 (terminal No. 106) engine-A/T-ECU connector. |
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Q.
Is the check result normal?
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Go to Step 6 . |
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Repair the damaged harness wire. |
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STEP 6. M.U.T.-III data list |
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Q.
Is the check result normal?
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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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Replace the engine-A/T-ECU. |
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STEP 7. Connector check: D-217 engine-A/T-ECU connector |
Q.
Is the check result normal?
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Go to Step 8 . |
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Repair or replace the connector. |
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STEP 8. Check harness between B-31 (terminal No. 2) electronic-controlled throttle valve connector and D-217 (terminal No. 106) engine-A/T-ECU connector. |
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Q.
Is the check result normal?
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Go to Step 9 . |
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Repair the damaged harness wire. |
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STEP 9. Check harness between B-31 (terminal No. 1) electronic-controlled throttle valve connector and D-217 (terminal No. 115) engine-A/T-ECU connector. |
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Q.
Is the check result normal?
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Go to Step 10 . |
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Repair the damaged harness wire. |
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STEP 10. M.U.T.-III diagnosis code |
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Q.
Is the diagnosis code set?
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Replace the engine-A/T-ECU. |
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Check end. |
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