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P0340






P0340-CAMSHAFT POSITION SENSOR CIRCUIT

For a complete wiring diagram, refer to the Wiring Information.





Theory of Operation

The Camshaft Position (CMP) Sensor circuits consist of an Powertrain Control Module (PCM) supplied 5-volt reference circuit, low reference circuit, and an output signal circuit. The CMP Sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes between the peaks and valleys of a tone wheel attached to the camshaft. As each tooth rotates past the CMP Sensor, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The sensor returns a digital ON/OFF DC voltage pulse of varying frequency output pulses per Camshaft revolution that represent an image of the camshaft tone wheel. The frequency of the CMP Sensor output depends on the velocity of the camshaft. The PCM decodes the tooth pattern to identify camshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The PCM also uses CMP Sensor output information to determine the camshaft relative position to the Crankshaft, to control the CMP Actuator operation if equipped.

- When Monitored:
During engine cranking and with the engine running. Battery voltage greater than 10 volts. No 5-Volt Supply or Crankshaft Position Sensor DTCs present.

- Set Condition:
The Powertrain Control Module (PCM) detects an implausible Camshaft Position Sensor signal during eight consecutive crankshaft revolutions. One Trip Fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, read DTCs. Copy DTC and Freeze Frame information.
3. Start the engine and allow it to reach operating temperature.

WARNING:
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

NOTE: Attempt to operate the vehicle under conditions similar to which the DTC was set.

NOTE: It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set.

4. With the scan tool, view DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Go To 10

2. (K441) CMP SIGNAL CIRCUIT
1. Turn the ignition off.
2. Disconnect the CMP Sensor harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (K441) CMP Sensor Signal circuit at the CMP Sensor harness connector.

Is the voltage between 4.8 and 5.2 volts?

Yes

- Go To 3

No

- Go To 6

3. (K900) SENSOR GROUND CIRCUIT OPEN/EXCESSIVE RESISTANCE
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Measure the resistance of the (K900) Sensor Ground circuit between the CMP Sensor harness connector and the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

- Repair the (K900) Sensor ground circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. (K441) CMP SENSOR SIGNAL CIRCUIT SHORTED TO THE (F855) 5-VOLT SUPPLY CIRCUIT
1. Measure the resistance between the (K441) CMP Sensor Signal circuit and the (F855) 5-Volt Supply circuit in the CMP Sensor harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 5

No

- Repair the short between the (K441) CMP Sensor Signal circuit and the (F855) 5-Volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

5. CAMSHAFT POSITION SENSOR

NOTE: Inspect the Camshaft tone wheel for damage. If a problem is found repair as necessary. .

Repair

- Verify that there is good pin to terminal contact in the CMP Sensor and Powertrain Control Module connectors. Replace the Camshaft Position Sensor if no problems were found with the connectors. .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. (K441) CMP SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Ignition on, engine not running.
4. Measure the voltage on the (K441) CMP Sensor Signal circuit at the CMP Sensor harness connector.

Is there any voltage present?

Yes

- Repair the short to voltage in the (K441) CMP Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 7

7. (K441) CMP SENSOR SIGNAL CIRCUIT OPEN/EXCESSIVE RESISTANCE
1. Turn the ignition off.
2. Measure the resistance of the (K441) CMP Sensor Signal circuit between the CMP Sensor harness connector and the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 8

No

- Repair the open or excessive resistance in the (K441) CMP Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

8. (K441) CMP SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
1. Measure the resistance between ground and the (K441) CMP Sensor Signal circuit in the CMP Sensor harness connector.

Is the resistance above 10K Ohms?

Yes

- Go To 9

No

- Repair the short to ground in the (K441) CMP Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

9. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the related Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related Sensor and the Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.

Were there any issues?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace and program the Powertrain Control Module. .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

10. ERRATIC CMP SIGNAL
1. With a lab scope, back probe the (K441) CMP Signal circuit in the CMP harness connector.

WARNING:
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

2. Ignition on, engine not running.
3. Wiggle the related wire harness and lightly tap the Camshaft Position Sensor.
4. Observe the lab scope screen.
5. Allow the engine to idle.
6. Observe the lab scope screen.

Did the CMP Sensor generate any erratic pulses?

Yes

- Verify that there is good pin to terminal contact in the CMP Sensor and the Powertrain Control Module connectors. If OK, inspect the Camshaft tone wheel for irregularities. If the tone wheel is distorted replace the Camshaft. . If no problems were found with the tone wheel, replace the Camshaft Position Sensor. .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 11

11. ERRATIC CKP SIGNAL
1. Turn the ignition off.
2. With a lab scope, backprobe the (K24) CKP Signal circuit in the CKP harness connector.

WARNING:
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

3. Ignition on, engine not running.
4. Wiggle the related wire harness and lightly tap on the Crankshaft Position Sensor.
5. Observe the lab scope screen.
6. Allow the engine to idle.
7. Observe the lab scope screen.

Did the CKP Sensor generate any erratic pulses?

Yes

- Verify that there is good pin to terminal contact in the CKP Sensor and the Powertrain Control Module connectors. If OK, replace the Crankshaft Position Sensor. Crankshaft Position Sensor - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Test complete, the conditions that set this DTC are not present at this time. Using the wiring diagram as a guide, check all related splices and connections for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.

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