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 JUDGMENT

Check Conditions

While engine is being cranked or is running.
Battery positive voltage is 6 - 16 V.

Judgment 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).
The AS&G control is prohibited.

PROBABLE CAUSES

Failed camshaft position sensor
Open/short circuit or harness damage in camshaft position sensor circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Perform voltage measurement at camshaft position sensor connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal engine-ECU SGC line and body earth.

OK: 4.9 - 5.1 V

Q. Is the check result normal?

	Go to Step 5.

	Go to Step 2.

STEP 2. Perform voltage measurement at engine-ECU connector.

Disconnect engine-ECU harness, and connect special tool power plant ECU check harness (MB992291) to measure at connector for inspection.
Disconnect camshaft position sensor connector.
Ignition switch: ON
Voltage between terminal SGC and body earth.

OK: 4.9 - 5.1 V

Q. Is the check result normal?

	Repair or replace the connector, or check and repair harness between camshaft sensor connector terminal and engine-ECU connector terminal SGC. Check output line for open circuit.

	Go to Step 3.

STEP 3. Check harness between camshaft position sensor connector terminal and engine-ECU connector terminal SGC.

Check output line for short circuit.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 4. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	Replace the engine-ECU.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 5. Perform voltage measurement at camshaft position sensor connector.

Use special tool test harness (MB991709) to connect connector, and measure at pick-up harness.
Ignition switch: ON
Voltage between terminal engine-ECU SGCB line and body earth.

OK: 4.9 - 5.1 V

Q. Is the check result normal?

	Go to Step 7.

	Go to Step 6.

STEP 6. Check harness between camshaft position sensor connector terminal and engine-ECU connector terminal SGCB.

Check power supply line for open/short circuit and damage.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 7. Perform resistance measurement at camshaft position sensor connector.

Disconnect connector, and measure at harness side.
Resistance between terminal engine-ECU SGCG line and body earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 9.

	Go to Step 8.

STEP 8. Check harness between camshaft position sensor connector terminal and engine-ECU connector terminal SGCG.

Check earthing line for open circuit and damage.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 9. Check harness between camshaft position sensor connector terminal and engine-ECU connector terminal SGC.

Check output line for damage.

Q. Is the check result normal?

	Go to Step 10.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 10. Perform output wave pattern measurement at camshaft position sensor (Using an oscilloscope).

Use special tool test harness (MB991709) to connect connector, and measure at pick-up harness.
Engine: Idling
Transmission: Neutral
Voltage between terminal engine-ECU 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.

Q. Is the check result normal?

	Go to Step 4.

	Go to Step 11.

STEP 11. Check camshaft position sensor for correct mounting condition.

Q. Is the check result normal?

	Go to Step 12.

	Repair.

STEP 12. Check camshaft sensing portion.

Q. Is the check result normal?

	Go to Step 13.

	Replace the inlet camshaft.

STEP 13. Replace the camshaft position sensor.

After replacing the camshaft position sensor, reconfirm whether the diagnosis code is set.

Q. Is the diagnosis code set?

	Replace the engine-ECU.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).