Code No. P0340: Camshaft Position Sensor System
OPERATION
- A power voltage of 5 V is applied to the camshaft position sensor power terminal from the engine-ECU connector terminal SGCB and earthed to engine-ECU connector terminal SGCG from the camshaft position sensor connector terminal.
- The sensor signal is inputted to the engine-ECU connector terminal SGC from the camshaft position sensor output terminal.
FUNCTION
- The camshaft position sensor detects the top dead centre on the compression stroke of the No. 1 cylinder and inputs a pulse signal to the engine-ECU.
TROUBLE JUDGEMENT
Check Conditions
- While engine is being cranked or is running.
- Battery positive voltage is 6 - 16 V.
Judgement Criterion
- The number of output pulses from the camshaft position sensor per engine rotation is 1 or less.
FAIL-SAFE AND BACKUP FUNCTION
- The rail pressure is controlled in the range between 50 and 100 MPa.
- The fuel injection amount is restricted (output restriction).
- The open angle of the accelerator pedal is restricted.
- The DPF regeneration is prohibited.
- The throttle valve is closed (fixed opening degree).
- The EGR control is stopped (fully closed).
PROBABLE CAUSES
- Failed camshaft position sensor
- Open/short circuit or harness damage in camshaft position sensor circuit or loose connector contact
- Failed engine-ECU
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STEP 1. Voltage measurement at camshaft position sensor connector (SGC line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(3)Measure the resistance between the camshaft position sensor connector (SGC 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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 Go to Step 2.
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STEP 2. Voltage measurement at engine-ECU connector (SGC 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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(2)Disconnect camshaft position sensor connector.
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(4)Check the voltage between the engine-ECU connector (SGC terminal) and body earth.
OK: 4.9 - 5.1 V
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Q.
Is the check result normal?
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Repair SGC line between camshaft position sensor connector and engine-ECU connector.
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Go to Step 3.
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STEP 3. Check of short to earth in SGC line between camshaft position sensor connector and engine-ECU connector.
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Q.
Is the check result normal?
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Go to Step 4.
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Repair the connector(s) or wiring harness.
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STEP 4. M.U.T.-III diagnosis code
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- Reconfirmation of diagnosis code.
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Q.
Is the diagnosis code set?
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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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STEP 5. Voltage measurement at camshaft position sensor connector (SGCB line).
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(1)Use special tool test harness (MB991709) to connect connector, and measure at pick-up harness.
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(3)Check the voltage between the camshaft position sensor connector (SGCB 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 7.
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Go to Step 6.
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STEP 6. Check of open circuit and damage in SGCB line between camshaft position sensor connector and engine-ECU connector.
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Q.
Is the check result normal?
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Go to Step 4.
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Repair the connector(s) or wiring harness.
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STEP 7. Resistance measurement at camshaft position sensor connector (SGCG 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 camshaft position sensor connector (SGCG 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 9.
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Go to Step 8.
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STEP 8. Check of open circuit and damage in SGCG line between engine-ECU connector and camshaft position sensor connector.
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Q.
Is the check result normal?
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Go to Step 4.
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Repair the connector(s) or wiring harness.
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STEP 9. Check of damage in SGC line between camshaft position sensor connector and engine-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 connector(s) or wiring harness.
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STEP 10. Perform output wave pattern measurement at camshaft position sensor (Using an oscilloscope).
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(1)Use special tool test harness (MB991709) to connect connector, and measure at pick-up harness.
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(4)Check the voltage between the camshaft position sensor connector (SGC line) and body earth.
OK: Waveforms should be displayed on Inspection procedure using an oscilloscope (Refer to  ), its maximum value should be 4.8 V or more, and its minimum valve should be 0.6 V or less with no noise in waveform.
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Q.
Is the check result normal?
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Go to Step 4.
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Go to Step 11.
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STEP 11. Check camshaft position sensor for correct mounting condition.
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Q.
Is the check result normal?
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Go to Step 12.
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Repair.
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STEP 12. Check camshaft sensing portion.
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Q.
Is the check result normal?
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Go to Step 13.
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Replace the inlet camshaft.
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STEP 13. Replace the camshaft position sensor.
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- After replacing the camshaft position sensor, reconfirm whether the diagnosis code is set.
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Q.
Is the diagnosis code set?
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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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