I have been experiencing an issue with my truck for about 1 year now. The truck idles extremely rough and ultimately the engine dies. I read the codes at one point in time and got P0340 (Camshaft position sensor). I replaced the sensor located on the front of the engine (drivers side) directly in front of the camshaft and the problem went away. 2 months later same problem. I took it to Ford and they told me I needed a new engine. I ran out of there, convinced they were on crack, I took the truck home and unplugged the sensor and the idle problem was gone. I later determined that with one sensor, either side (driver or passenger) the truck runs fine however with both the problem occurs. Then just recently the problem went away again for about two months no issue with both sensors plugged in. Now the problem is back and I am about tired of dealing with this. The check engine light come on/off and blinks. Also, in addition to a rough idle I now have misfiring at speed (3rd/4th gear) with one sensor plugged in.

I am planning to take it to a different dealer, however I wanted to get some insight if possible. Thanks for your help in advance.

 

P0340 - Camshaft Position (CMP) Sensor Circuit Malfunction (Bank 1)
Description: The test fails when the powertrain control module (PCM) can no longer detect the signal from the CMP sensor on bank 1.
Possible Causes: CMP circuit open.
CMP circuit short to GND.
CMP circuit short to PWR.
SIG RTN open (VR sensor).
CMP GND open (Hall-effect sensor).
CMP circuit short to CMP2 circuit (if equipped).
CMP incorrectly installed (Hall-effect sensor).
Damaged CMP sensor shielding.
Damaged CMP sensor.
Damaged PCM.

Diagnostic Aids: Harness routing, harness alterations, improper shielding, or electrical interference from other improperly functioning systems may have an intermittent impact on the CMP signal.
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to DR1

 

DR1 CONTINUOUS MEMORY DTCS P0340 AND P0345: CHECK IF THE ENGINE WILL START
Attempt to start the engine.
Does the engine start?
Yes No
GO to DR2 . Concern is elsewhere. RETURN to Section 3 , Symptom Charts for further direction.

DR2 CLEAR AND ATTEMPT TO RETRIEVE THE DTC
Key in ON position.
Clear the PCM DTCs.
Key on engine running.
Increase engine speed to greater than 1,500 RPM for 10 seconds.
Repeat this 3 times.
Retrieve the continuous memory DTCs.
Are DTCs P0340 or P0345 present?
Yes No
For continuous memory DTC P0340, GO to DR3 .

For continuous memory DTC P0345, GO to DR11 . GO to Z1 .

DR3 DETERMINE THE CMP SENSOR PHYSICAL TYPE
Key in OFF position.
Is the CMP sensor a synchronizer (gear driven) type?
Yes No
GO to DR4 . GO to DR5 .

DR4 VERIFY THE CORRECT INSTALLATION OF THE CMP SENSOR
A CMP sensor identifies the cylinder 1 power stroke. A sensor that is improperly installed/indexed can identify the wrong cylinder as 1, produce a tip-in hesitation and generate DTC P0340.
Note: If the vehicle has a miss with DTC P0340, ignition, alternator noise, RFI and CKP concerns should be considered.

Is the CMP sensor installed correctly?
Yes No
GO to DR5 . INSTALL the CMP sensor correctly.

REFER to the Workshop Manual Section 303-14 Electronic Engine Controls for additional information.

DR5 DETERMINE THE CMP SENSOR ELECTRONIC TYPE
Note: The variable reluctance (VR) sensors have 2-wire connectors, Hall-effect sensors have 3-wire connectors.

Is the CMP sensor a VR-type?
Yes No
Key in OFF position.

GO to DR6 . The CMP sensor is a Hall-effect type.

GO to DR17 .

DR6 CONTINUOUS MEMORY DTC P0340: CHECK THE CMP SENSOR RESISTANCE
CMP Sensor connector disconnected.
Measure the resistance between:

( + ) CMP Sensor Connector, Component Side ( - ) CMP Sensor Connector, Component Side
CMP SIGRTN



Vehicle Low Limit High Limit
LS, Thunderbird 3.9L 1,850 Ohms 2,850 Ohms
F-150 300 Ohms 425 Ohms
All others 250 Ohms 1,000 Ohms


Is the resistance within specification?
Yes No
GO to DR7 . INSTALL a new CMP sensor.

Clear the PCM DTCs. REPEAT the self-test.

DR7 CHECK THE CMP CIRCUIT FOR A SHORT TO POWER IN THE HARNESS
PCM connector disconnected.
Key in ON position.
Measure the voltage between:

( + ) CMP Sensor Connector, Harness Side ( - ) Vehicle Battery
CMP Negative terminal


Is the voltage less than 1 V?
Yes No
Key in OFF position.

GO to DR8 . REPAIR the short circuit.

 

Thanks for the post, but preferribly in laymen terms.

 

Decent flow (esp since I have P0340 and P0345 present).

Is z1 something like "check alternator for bad diode or other noise defect" (two TSBs on alternator causing P0340 and/or P0345 now)?

Or perhaps a continuation of debugging the cable harness?