Code No. P0340: Camshaft Position Sensor System

OPERATION

Power is supplied to the camshaft position sensor connector terminal from the engine control relay connector terminal and is earthed to the engine-ECU connector terminal DGND from the camshaft position sensor connector terminal.
A power voltage of 5 V is applied to the camshaft position sensor connector signal terminal from the engine-ECU connector terminal SGC.

FUNCTION

The camshaft position sensor detects the position of the camshaft and inputs the pulse signal to the engine-ECU.
In response to the camshaft position sensor signal and the crank angle sensor signal, the engine-ECU detects the compression top dead centre of the No. 1 cylinder.

TROUBLE JUDGEMENT

Check Condition, Judgement Criterion

Normal signal pattern has not been input for cylinder identification from the crank angle sensor signal and camshaft position sensor signal for 2 seconds.

Check Condition

Engine is being cranked.

Judgement Criterion

Camshaft position sensor output voltage has not changed (no pulse signal is input) for 2 seconds.

FAIL-SAFE AND BACKUP FUNCTION

Engine runs in learned pattern until engine stops.

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 4.

	Go to Step 2.

STEP 2. Check of open circuit, and short circuit in SGC line between camshaft position sensor connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 3.

	Repair the connector(s) or wiring harness.

STEP 3. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is 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 4. Perform voltage measurement at camshaft position sensor connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal power supply line and body earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 5.

	Repair or replace the connector(s), or check and repair the harness of open circuit, and short circuit in power supply line between camshaft position sensor connector and engine control relay connector.

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

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

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 7.

	Go to Step 6.

STEP 6. Check of open circuit, and damage in DGND line between camshaft position sensor connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 3.

	Repair the connector(s) or wiring harness.

STEP 7. Perform output wave pattern measurement at camshaft position sensor connector (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 value should be 0.6 V or less. There must be no noise in the output wave pattern.

Q. Is the check result normal?

	Go to Step 3.

	Go to Step 8.

STEP 8. Check of damage in power supply line between camshaft position sensor connector and engine control relay connector.

Q. Is the check result normal?

	Go to Step 9.

	Repair the connector(s) or wiring harness.

STEP 9. Check of damage in SGC line between camshaft position sensor connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 10.

	Repair the connector(s) or wiring harness.

STEP 10. Check camshaft position sensing cylinder.

Q. Is the check result normal?

	Go to Step 11.

	Replace the cam position sensing cylinder.

STEP 11. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is diagnosis code set?

	Replace the camshaft position sensor.

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