P0340 Code - Cam Sensors

[SusieR57]

Has anyone ever had this issue - Check engine light came on at American Muscle. Changed out both sensors, cleared code drove for a short while and then the check engine light came back on. I'm going to install dealer cam sensors to see if maybe the aftermarket ones were no good. If that does't work, it could possibly be the alternator. (I don't want to go there just yet!)
Looking for any input or if you actually may have had this problem.
2006 with 76K miles

Thanks,
Susie

[Blackgt09]

I had the same issue. My 09 was running horrible I had that code plus one other that I can remeber. Ended up being the clip going to the cam sensor on the passenger side.

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[Hotshot]

from what I hear from our techs is that a diode burns out in the alt and backfeeds some bad RFI siginals that trip that po340 code for a cam sensor

and here is a TSB actually

Charging System - DTC P0340/P0344/P0345/P0349
TSB 06-19-12
10/02/06
DTC P0340/P0344/P0345/P0349-4.6L 3V AND 5.4L 3V
FORD:
2005-2006 Mustang
2004-2005 F-150
2005-2006 Expedition, F-Super Duty
2006 Explorer
2007 Explorer Sport Trac
LINCOLN:
2005-2006 Navigator
MERCURY:
2006 Mountaineer
This article supersedes TSB 06-2-9 to add a production fix date for Expedition and Navigator and service parts updated.
ISSUE
Some 2005-2006 F-Super Duty and Expedition/Navigator vehicles built prior to 12/14/2005 and 2004-2005 F-150 vehicles, equipped with 5.4L 3V engine, and 2005-2006 Mustang GT vehicles, equipped with 4.6L 3V engine, may exhibit a diagnostic trouble code (DTC) P0340 and/or P0344; or 2006 Explorer 4dr/Mountaineer and 2007 Explorer Sport Trac vehicles equipped with a 4.6L 3V engine may exhibit a DTC P0345 and/or P0349. This may be due to a malfunctioning diode or open phase connection in the generator.
ACTION
Perform a generator frequency test to diagnose cause of concern. Do not replace the generator unless a frequency test indicates a fault. This TSB provides step-by-step directions for performing a generator frequency test using the WDS oscilloscope function.
SERVICE PROCEDURE
NOTE USING THE OSCILLOSCOPE TO MEASURE PEAK-TO-PEAK VOLTAGE IS NOT A GOOD INDICATOR OF A FAULTY GENERATOR.
NOTE ENSURE THERE IS NO BATTERY CHARGER CONNECTED TO THE VEHICLE.
1. Ensure the connections to the battery terminals, engine grounds, and generator B+ are clean and secure.
2. Attach WDS battery cable clamps to battery/battery cables.
3. Turn on WDS.
4. Select the Toolbox Icon, (upper left of WDS screen).
5. Select Oscilloscope and then click OK.
6. Select Channel 1, Auto, Generator Ripple.
7. Select Calculations, Channel 1, Frequency.
8. Select Calculations again.
9. Push the RUN/STOP button. A waveform should display on the screen.
10. Start the vehicle and leave at idle (engine speed less than 800 RPM).
11. Turn on vehicle loads (high beams, blower set on high, heated seats, defroster, etc).
12. Examine the frequency reading on WDS.
NOTE WDS CAN CALCULATE THE FREQUENCY AUTOMATICALLY. THE CALCULATED FREQUENCY IS LOCATED ON THE LOWER LEFT AREA OF THE OSCILLOSCOPE SCREEN. SOMETIMES THE FREQUENCY CANNOT BE CALCULATED BECAUSE THE WDS CANNOT RECOGNIZE AND MEASURE PEAK VALUES. IF THE WDS CANNOT CALCULATE THE FREQUENCY, IT WILL DISPLAY "INVALID" WHERE THE FREQUENCY READING SHOULD BE. THIS IS NORMAL IF THE RIPPLE VOLTAGE IS TOO LOW.
13. For a proper visible wave pattern, adjust the voltage scale and time scale until a good wave pattern is visible. Typically, a setting of 1mS/div and 100mV/div is a good starting point and can be adjusted as necessary.
14. Run vehicle until signal is steady. Then select the "RUN/STOP" button to freeze the waveform.
15. Determine if the generator is faulty based on frequency measurement:
NOTE FREQUENCY IS DEPENDENT ON ENGINE RPM. PERFORM ALL TESTS AT IDLE OR FREQUENCY READINGS WILL BE INACCURATE.



a. Compare the WDS saved waveform to the sample waveforms in Figure 1. If measured ripple frequency is lower than 500 Hz, then generator is faulty and should be replaced. If generator is not faulty proceed to Step 16.
b. If frequency calculation cannot be made by WDS, it can be calculated manually. See MANUALLY CALCULATE FREQUENCY. If calculated ripple frequency is lower than 500 Hz, then generator is faulty and should be replaced. If generator is not faulty proceed to Step 16.
MANUALLY CALCULATE FREQUENCY
^ Count the number of complete voltage dips over a given range of divisions on the scope trace
^ Divide the number of voltage dips by the number of divisions to get the average voltage dips/division
^ Divide the value in Step 2 by the time scale (e.g. 1mS/div = .001 sec/division) to get frequency
NOTE THIS METHOD OF CALCULATING FREQUENCY IS SLIGHTLY DIFFERENT THAN THE METHOD USED BY WDS, SO THE FREQUENCY MEASUREMENT VS. CALCULATED MAY BE SLIGHTLY DIFFERENT.
16. If the frequency test does not indicate a fault with the generator, proceed with normal Powertrain Controls/Emissions Diagnosis (PC/ED) diagnostics for the DTC. For F-Super Duty vehicles only, if the DTCs are still present after diagnostics, reprogram the powertrain control module (PCM) to the latest calibration using WDS release B38.11 and higher or B39.2 and higher. Calibration files may also be obtained at the website. This new calibration is not included in the B39 CD. (DO NOT REPROGRAM EXPEDITION/NAVIGATOR, F-150, MUSTANG, EXPLORER, MOUNTAINEER OR EXPLORER SPORT TRAC).



Parts Block
WARRANTY STATUS: Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
OPERATION DESCRIPTION TIME

061912A 2005-2006 0.8 Hr.
Expedition/Navigator 5.4L
3V: Diagnose Generator
Using WDS, If Generator
Is Found Defective
Replace Generator (Do
Not Use With 10346A,
10200A)

061912B 2005-2006 Super Duty, 0.9 Hr.
2004-2005 F-150 5.4L 3V:
Diagnose Generator Using
WDS, If Generator Is
Found Defective Replace
Generator (Do Not Use
With 10346A, 10200A)

061912C 2005-2006 Super Duty, 0.6 Hr.
5.4L 3V: Diagnose
Generator Using WDS, If
Generator Is Found To Be
Functioning Properly
Reprogram The Powertrain
Control Module (Do Not
Use With 10346A, 10200A,
12650D, 12650D84)

061912D 2005-2006 Mustang 4.6L 0.8 Hr.
3V: Diagnose Generator
Using WDS, If Generator
Is Found Defective
Replace Generator (Do
Not Use With 10346A
10200A, 9926A, 12650D,
1 2650D84)

061912E 2006 1.1 Hrs.
Explorer/Mountaineer/2007
Explorer Sport Trac 4.6L
3V: Diagnose Generator
Using WDS, If Generator
Is Found Defective
Replace Generator. (Do
Not Use With 10346A
10200A, 9926A, 12650D,
1 2650D84)

DEALER CODING
CONDITION
BASIC PART NO. CODE
10346 42

[SusieR57]

Thanks James - this is basically what All-Data is saying also.