Ford P0340 error code.

[JerichoFan]

I have a 1997 Ford Aerostar with the 3.0L Vulcan engine, 86,000 miles. My check engine light is on, and it has the following error codes:
P0340 - CMP sensor circuit fault
P0340-C CMP sensor circuit malfunction

I have an obd 2 cable, and I use obd 2 software called FORScan, so I can reset the DTCs. I can also see the status of the camshaft position sensor. When I start the engine, FORScan says the status of the camshaft position sensor is OK. After a minute or two, it goes to FAULT, P0340 and P0340-c come up, and the check engine light comes on. I have been trying to fix this for a while now. I have done research online and tried a whole bunch of things.

This is what I have tried:

• Replaced camshaft synchronizer twice (Both were new).
• Replaced camshaft position sensor. I've had 5 different sensors in it. Some were put in another Aerostar I have to see if they worked and they did.
• Switched the synchronizer and sensor with another Aerostar that is working. This Aerostar still has the check engine light come on, the other Aerostar does not.
• I have taken out the #1 spark plug, found top dead center, and checked to make sure the synchronizer is in the correct position.
• Put the timing gear and synchronizer in exact same position as my working aerostar.
• I checked the wiring to the sensor. Looked for damaged wires, and checked for continuity from the camshaft position sensor to the PCM. All checked out okay.
• Switched the PCM with another Aerostar. PCM checked out okay.
• Changed the crankshaft position sensor.
• Wrapped the camshaft position sensor and the alternator in aluminum foil. This was due to someone saying the alternator may interfere with the sensor.

Nothing I have tried has fixed it. Does anyone have any suggestions?

 

[BrooklynBay]

Do you have a timing light? Do you have access to an alignment tool?

 

[JerichoFan]

Do you have a timing light? Do you have access to an alignment tool?

Hello BrooklynBay,
Yes. I have a timing light. I also have the alignment tool that came with the camshaft synchronizer.

 

[BrooklynBay]

Contact @2000StreetRod. He might have an idea about what to do.

 

[2000StreetRod]

According to the 1997 MY OBD System Operation Summary for Gasoline Engines the Comprehensive Component Monitor - Engine, Ignition:
"Electronic Ignition systems (Electronic Distributorless Ignition System - EDIS or Coil on Plug - COP) systems are being used on all applications.
The EDIS system uses a chip to process the 36 (or 40) tooth crankshaft position signal, generate a low data rate PIP signal for the PCM microprocessor and control a 4 or 6 terminal coil pack which fires a pair of spark plugs. One of these sparkplugs is on the compression stroke, while the other is on the exhaust stroke. The EDIS chip can be incorporated within the PCM or in a separate ignition control module. . .
The ignition system is checked by monitoring three ignition signals during normal vehicle operation:
Profile Ignition Pickup (CKP, commonly known as PIP), the timing reference signal derived from the crankshaft 36-tooth wheel and processed by the EDIS chip. PIP is a 50% duty cycle, square wave signal that has a rising edge at 10 deg BTDC.
Camshaft IDentification (CMP, commonly known at CID), a signal derived from the camshaft to identify the #1 cylinder
Ignition Diagnostic Monitor (IDM), a signal that indicates that the primary side of the coil has fired. This signal is received as a digital pulse width signal from the EDIS chip. The EDIS chip determines if the current flow to the ignition coil reaches the required current (typically 5.5 Amps for COP, 3.0 to 4.0 Amps for DIS) within a specified time period (typically > 200 microseconds for both COP and DIS). The EDIS chip also outputs status information when the engine is not running.
First, the relationship between successive PIP events is evaluated to determine whether the PIP signal is rational. Too large a change in 3 successive PIP indicates a missing or noisy PIP signal (P0320). Next, the CMP edge count is compared to the PIP edge count. If the proper ratio of CMP events to PIP events is not being maintained (for example, 1 CMP edge for every 8 PIP edges for an 8-cylinder engine), it indicates a missing or noisy CMP signal (P0340). Finally, the relationship between IDM edges and PIP edges is evaluated. If there is not an IDM edge (coil firing) for every PIP edge (commanded spark event), the PCM will look for a pattern of failed IDM events to determine which ignition coil has failed. If the ignition coil cannot be identified or if the engine is running and there are no IDM edges, the IDM circuit is malfunctioning (P1351). . .
Typical ignition check malfunction thresholds:
For PIP: Time between PIP edges: > 350 milliseconds
Ratio of current PIP period to last two periods: < 0.75, > 1.75
For CMP: Ratio of PIP events to CMP events: 4:1, 6:1, 8:1 or 10:1 based on engine cyl.
For coils: Ratio of PIP events to IDM events: 1:1 "

I'm not familiar with the 3.0L V6 but it seems to me that replacing the camshaft position sensor and the crankshaft position sensor were logical actions since they're functionally related. Checking the wiring was also appropriate. Its unlikely that the engine would run properly without a functional crankshaft position sensor but you might try cleaning the connector by disconnecting and reconnecting it a few times. Unfortunately, I don't have access to electrical wiring diagrams for your vehicle. Rock Auto lists an ignition control module for your vehicle.

I suggest that you confirm you have one and if so check the connections to it. As I recall the camshaft position sensor (synchronizer) on the 4.0L OHV engine is driven by a shaft common with the oil pump. Have you confirmed that the synchronizer actually rotates when the crankshaft is rotated? Maybe it is not fully seated on the shaft that drives it.