P0343

P0343 Camshaft Position Sensor A Circuit High Input

Component Location






General Description
The Camshaft Position Sensor (CM PS) is a sensor that detects the compression TDC of the NO.1 cylinder. The CMPS consists of a hall type sensor and a target on the end of the intake camshaft. When the target triggers the sensor, the sensor voltage is 5V. If not, the sensor voltage is 0V. These CMPS signal is sent to the ECM and the ECM uses the CMPS signal for synchronizing the firing of sequential fuel injectors.

DTC Description
If the output voltage of CMPS remains high longer than 2sec. when the change of CKPS output voltage is zero, the ECM determines that a fault exists and a DTC is stored.

DTC Detecting Condition






Schematic Diagram







Signal Waveform







Monitor Scantool Data

1. Connect scantool and Engine ON

2. Monitor Signal waveform of CMPS with scantool.






3. Is the measured signal waveform of CMPS displayed correctly?

YES

- Fault is intermittent caused by poor contact in the sensors and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness poor connection~bending corrosion contamination deterioration or damage. Repair or replace as necessary and go to Verification vehicle Repair procedure.

NO

- Go to W/Harness Inspection procedure.

Terminal and Connector Inspection

1. Many malfunctions in the electrical system are caused by poor harness and terminals.
Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

3. Has a problem been found?

YES

- Repair as necessary and go to "Verification of Vehicle Repair" procedure.

NO

- Go to "Signal Circuit Inspection" procedure.


Signal Circuit Inspection

1. Check voltage

(1) Ignition "OFF"

(2) Disconnect CMPS connector.

(3) Ignition "ON" & Engine "OFF"

(4) Measure voltage between terminal "2" of CMPS harness connector and chassis ground.
Specification : 5V






(5) Is the measured voltage within specifications?

YES

- Go to Ground Circuit Inspection procedure.

NO

- Go to Check for short to battery in harness as below.


2. Check for short to battery in harness

(1) Ignition OFF"

(2) Disconnect CMPS connector and ECM connector

(3) Measure resistance between terminals 2 and 1 of CMPS harness connector.
Specification : Infinite






(4) Is the measured resistance within specifications?

YES

- Go to Check for open in harness as below.

NO

- Check short to battery in signal harness.

- Repair or replace as necessary and then, go to Verification of Vehicle Repair procedure.

3. Check for open in harness

(1) Ignition "OFF"

(2) Disconnect CMPS and ECM connector.

(3) Measure resistance between terminal "2" of CMPS harness connector and terminal "B10" of ECM harness connector.
Specification : Approx. below 1 ohm






(4) Is the measured resistance within specifications?

YES

- Go to Ground Circuit Inspection procedure.

NO

- Check open in harness between CMPS connector and ECM connector.

- Repair or replace as necessary and then, go to Verification of Vehicle Repair procedure.

Ground Circuit inspection

1. Check for open in harness

(1) Ignition "OFF"

(2) Disconnect CMPS and ECM connector.

(3) Measure resistance between terminal "3" of CMPS harness connector and chassis ground.
Specification : Approx. below 1 ohm






4) Is the measured resistance within specifications?

YES

- Go to Component Inspection procedure.

NO

- Check open in harness.

- Repair or replace as necessary and then, go to Verification of Vehicle Repair procedure.


Component Inspection
1. Check CMPS

(1) Connect CMPS and ECM connector.

(2) Engine "ON" & monitor the signal waveform of CMPS on scantool.

Specification : Check whether the waveform is synchronized with Crankshaft Position Sensor or not.






(3) Is the signal waveform normal?

YES

- Substitute with a known - good ECM and check for proper operation.
If the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure.

NO

- Substitute with a known - good CMPS and check for proper operation.
If the problem is corrected, replace CMPS and go to "Verification of Vehicle Repair" procedure.

Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.

1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.

2. Using a Scantool, Clear the DTCs.

3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions.

4. Monitor that all readiness test have been verified as Complete~

5. Are any DTCs present?

YES

- Go to the applicable troubleshooting procedure.

NO

- System is performing to specification at this time.