Code No. P1428: No. 3 Exhaust Gas Temperature Sensor (DPF Temperature) Circuit High Input
OPERATION
- A power voltage of 5 V is applied to the No. 3 exhaust gas temperature sensor (DPF temperature) output terminal from the engine-ECU connector terminal DTS3.
- The power voltage is earthed to the engine-ECU connector terminal DT3E from the No. 3 exhaust gas temperature sensor (DPF temperature) connector terminal.
FUNCTION
- The No. 3 exhaust gas temperature sensor (DPF temperature) converts the DPF temperature into a voltage and inputs the voltage signal to the engine-ECU.
- Engine-ECU uses this voltage for DPF regeneration control.
- The No. 3 exhaust gas temperature sensor (DPF temperature) is a kind of resistor, which has characteristics to reduce its resistance as the DPF temperature rises. Therefore, the sensor output voltage varies with the DPF temperature, and becomes lower as the DPF temperature rises.
TROUBLE JUDGEMENT
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.
- Vehicle speed is 20 km/h or higher.
Judgement Criterion
- The No. 3 exhaust gas temperature sensor (DPF temperature) output voltage is 4.95 V or more.
FAIL-SAFE AND BACKUP FUNCTION
- The throttle valve is opened (electrical discontinuity).
- The EGR control is stopped (fully closed).
- The DPF regeneration is prohibited.
PROBABLE CAUSES
- Failed No. 3 exhaust gas temperature sensor (DPF temperature)
- Open circuit or harness damage in No. 3 exhaust gas temperature sensor (DPF temperature) circuit or loose connector contact
- Failed engine-ECU
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STEP 1. M.U.T.-III data list
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- Refer to Data List Reference Table
- Item 119: No. 3 exhaust gas temperature sensor (DPF temperature)
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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. Check No. 3 exhaust gas temperature sensor (DPF temperature) itself.
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- Check No. 3 exhaust gas temperature sensor (DPF temperature) itself (Refer to GROUP 17 - Emission Control <DIESEL> - Diesel Particulate Filter (DPF) System - No. 3 exhaust gas temperature sensor (DPF temperature) Check ).
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Q.
Is the check result normal?
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Go to Step 3.
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Replace the No. 3 exhaust gas temperature sensor (DPF temperature). After replacing the No. 3 exhaust gas temperature sensor (DPF temperature), carry out the forcible DPF regeneration. (Refer to GROUP 17 - Emission Control <DIESEL> - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).
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STEP 3. Voltage measurement at No. 3 exhaust gas temperature sensor (DPF temperature) connector (DTS3 line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(3)Check the voltage between the No. 3 exhaust gas temperature sensor (DPF temperature) connector (DTS3 line) and body earth.
OK: 4.5 - 4.9 V
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Q.
Is the check result normal?
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Go to Step 6.
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Go to Step 4.
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STEP 4. Check of open circuit in DTS3 line between No. 3 exhaust gas temperature sensor (DPF temperature) connector and engine-ECU connector.
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Q.
Is the check result normal?
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Go to Step 5.
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Repair the connector(s) or wiring harness.
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STEP 5. M.U.T.-III data list
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- Refer to Data List Reference Table
- Item 119: No. 3 exhaust gas temperature sensor (DPF temperature)
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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-ECU.
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STEP 6. Resistance measurement at No. 3 exhaust gas temperature sensor (DPF temperature) connector (DT3E 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 No. 3 exhaust gas temperature sensor (DPF temperature) connector (DT3E 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 8.
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Go to Step 7.
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STEP 7. Check of open circuit and damage in DT3E line between engine-ECU connector and No. 3 exhaust gas temperature sensor (DPF temperature) connector.
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Q.
Is the check result normal?
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Go to Step 5.
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Repair the connector(s) or wiring harness.
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STEP 8. Check of damage in DTS3 line between engine-ECU connector and No. 3 exhaust gas temperature sensor (DPF temperature) connector.
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Q.
Is the check result normal?
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Go to Step 5.
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Repair the connector(s) or wiring harness.
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