Circuit Description
The camshaft position (CMP) sensor is a hall-effect type sensor that works in conjunction with a 1X reluctor wheel on the camshaft. The powertrain control module (PCM) provides the CMP sensor with the following:
| • | A 12 volt reference circuit |
| • | A low reference circuit |
| • | A signal circuit |
The CMP sensor produces one signal for each revolution of the camshaft to control sequential fuel injection. If the PCM receives the crankshaft position (CKP) sensor signal, the engine will start and run without a CMP signal. If the PCM receives an incorrect number of pulses or no pulses on the CMP signal circuit, DTC P0340 will set.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
There is no change in CMP activity for 30 crankshaft revolutions.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | If the PCM sees less than 15 resyncs in 256 seconds, the counter resets to 0. If a poor connection is present, the CMP sensor active counter stops incrementing and the CMP sensor resync counter starts to increment. |
| • | The following conditions may cause this DTC to set: |
| - | Incorrect harness routing near the secondary ignition components |
| - | An ignition coil arcing to the wiring harness or the ignition control (IC) module. Inspect the ignition coils for cracks, for carbon tracking, or for other signs of damage. |
| - | The camshaft reluctor wheel is damaged. |
| - | The sensor is coming in contact with the reluctor wheel. |
| - | Foreign material is passing between the sensor and the reluctor wheel. |
| - | Camshaft end-play is excessive. |
If the condition is intermittent, refer to Intermittent Conditions .
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | ||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||
2 |
Does the CMP Active Counter increment? | -- | Go to Step 3 | Go to Step 4 | ||||||
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids | ||||||
4 |
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 7 | ||||||
5 |
Is the voltage more than the specified value? | 0.2 V | Go to Step 8 | Go to Step 6 | ||||||
Does the CMP Active Counter increment when the test lamp contacts the signal circuit? | -- | Go to Step 10 | Go to Step 9 | |||||||
7 | Test the 12-volt reference circuit for the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 11 | ||||||
8 | Test the low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 11 | ||||||
9 | Test the signal circuit for an open, a short to ground or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 11 | ||||||
10 | Test for an intermittent and for a poor connection at the CMP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 12 | ||||||
11 | Test for an intermittent and for a poor connection at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 | ||||||
12 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 | ||||||
13 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14 | ||||||
14 | Replace the CMP sensor. Refer to Camshaft Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- | ||||||
15 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- | ||||||
16 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 17 | ||||||
17 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||
