P0340
Camshaft Position Sensor Circuit:
Connector: C-40:
CIRCUIT OPERATION
- The camshaft position sensor power is supplied from the MFI relay (terminal 1). Ground is provided through terminal 7 to chassis ground.
- A 5-volt voltage is applied on the camshaft position sensor output terminal (terminal 5) from the PCM (terminal 56). The camshaft position sensor generates a pulse signal when the output terminal is opened and grounded.
TECHNICAL DESCRIPTION
- The camshaft position sensor functions to detect the top dead center position of the number 1 cylinder and to convert that data to pulse signals that are input to the PCM.
- When the engine is running, the camshaft position sensor outputs a pulse signal.
- The PCM checks whether pulse signal is input while the engine is cranking.
DTC SET CONDITIONS
Check Conditions
- Engine speed is higher than 50 r/min.
Judgment Criteria
- Camshaft position sensor output voltage has not changed (no pulse signal is input) for 2 seconds.
Check Conditions
- Engine speed is higher than 50 r/min.
Judgment Criteria
- Normal signal pattern has not been input for cylinder identification from the crankshaft position sensor signal and camshaft position sensor signal for 2 seconds.
TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- Camshaft position sensor failed.
- Open or shorted camshaft position sensor circuit, or loose connector.
- PCM failed.
DIAGNOSIS
Required Special Tool:
MB991348: Test Harness
STEP 1. Check the power supply line at the camshaft position sensor connector B-27.
1. Disconnect connector B-27 and measure at the harness side.
2. Turn the ignition switch to "ON" position.
3. Measure voltage between terminal 6 and ground.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to "LOCK" (OFF) position.
If within specifications, go to Step 2.
If not within specifications, repair the harness wire between the MFI relay connector A-21X and the camshaft position sensor connector B-27. Then go to Step 8.
STEP 2. Check the ground line at the camshaft position sensor connector B-27.
1. Disconnect connector B-27 and measure at the harness side.
2. Check for continuity between terminal 7 and ground.
- Should be less than 2 Ohms.
If less than 2 Ohms, go to Step 3.
If open circuit, repair the wire between the camshaft position sensor connector B-27 and ground. Then go to Step 8.
STEP 3. Check the output line at the camshaft position sensor connector B-27.
1. Disconnect connector B-27 and measure at the harness side.
2. Turn the ignition switch to "ON" position.
3. Measure voltage between terminal 5 and ground.
- Voltage should be between 4.8 and 5.2 volts
4. Turn the ignition switch to "LOCK" (OFF) position.
If within specifications, go to Step 4.
If not within specifications, go to Step 5.
STEP 4. Check the harness connector B-27 at the camshaft position sensor for damage.
If harness connector B-27 is damaged, repair or replace it. Refer to Harness Connector Inspection. Then go to Step 8.
If the harness connector B-27 is in good condition, replace the camshaft position sensor. Then go to Step 8.
STEP 5. Check the harness connector C-40 at the PCM for damage.
If harness connector C-40 is damaged, repair or replace it.
Refer to Harness Connector Inspection. Then go to Step 8.
If harness connector C-40 is in good condition, go to step 6.
STEP 6. Check the harness wire between the camshaft position sensor connector B-27 and the PCM connector C-40.
If the wire between the camshaft position sensor connector B-27 and the PCM connector C-40 is not damaged, go to Step 7.
If the wire between the camshaft position sensor connector B-27 and the PCM connector C-40 is damaged, repair it.
Then go to Step 8.
STEP 7. Using the oscilloscope, check the camshaft position sensor.
1. Disconnect the camshaft position sensor connector B-27, and connect the test harness special tool (MB991348) in between. (All terminals should be connected.)
2. Connect the oscilloscope probe to the camshaft position sensor side connector terminal 5.
NOTE: When measuring with the PCM side connector, connect an oscilloscope probe to terminal 56.
3. Start the engine and run at idle.
4. Check the waveform.
- The waveform should show a normal pattern similar to the illustration.
5. Turn the ignition switch to "LOCK" (OFF) position.
If the waveform does not show a normal pattern, replace the PCM. Then go to Step 8.
If the waveform shows a normal pattern, this malfunction is intermittent. Refer to How to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction
STEP 8. Test the OBD-II drive cycle
1. Carry out a test drive with the drive cycle pattern. Refer to Procedure 6 - Other Monitor.
2. Read the diagnostic trouble code, and confirm that diagnostic trouble code P0340 does not reset.