DTC P0340
Camshaft Position (CMP) Sensor Circuit
Circuit/System Description
The hall effect camshaft position (CMP) sensor produces 3 ON/OFF pulses for each revolution of the camshaft. The CMP output is pulse width encoded. The engine control module (ECM) uses the CMP and crankshaft position (CKP) output pulses to determine the engine speed and position. The CMP is connected directly to the ECM by the following circuits:
The 5-volt reference circuit
The low reference circuit
The CMP sensor signal circuit
Conditions for Running the DTC
The ignition is ON.
The engine is turning faster than 50 RPM.
DTC P0340 runs continuously when the above conditions are met.
DTCs P0335, P0336, P0642, or P0643 are not set.
Conditions for Setting the DTC
The ECM does not see a CMP sensor signal for more than 2 seconds.
Action Taken When the DTC Sets
DTC P0340 is a Type A DTC.
Conditions for Clearing the MIL/DTC
DTC P0340 is a Type A DTC.
Diagnostic Aids
If the CMP sensor signal is lost while running, the engine will operate normally. If the CMP sensor signal is not present on start-up, the engine will not start.
Circuit/System Verification
If DTCs P0642 or P0643 are set, diagnose those DTCs first.
Engine running, observe the DTC information with a scan tool. DTC P0340 should not set.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Disconnect the CMP sensor.
Test for less than 1 ohm between low reference circuit terminal 2 on the ECM side of the connector and ground.
If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 on the ECM side of the connector and ground.
If less that the specified range, test the 5-volt reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal 1 on the ECM side of the connector and ground.
If less than the specified range, test the affected signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
If greater than the specified range, test the affected signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
Ignition OFF, connect a 3A fused jumper wire to the CMP signal circuit terminal 1 on the ECM side of the connector.
Ignition ON, momentarily touch the end of the fused jumper wire to ground. The CAM signal present and the engine RPM parameters on the scan tool should change.
If the CAM signal present and the engine RPM does not change, replace the ECM.
Ignition OFF, inspect the wiring harness for any damage, opens or shorts.
If the circuits test normal, replace the CMP sensor.
