Any one have there car throw the po394 code?

 

P0394: Exhaust Cam Position Circuit Intermittent Bank 2


I've never seen it, but that is what the book says about it.

 

This 'might' help you a little.



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HomeEngine Trouble CodesEngine Trouble Code - P0394

P0394
Camshaft Position Sensor "B" Circuit Intermittent (Bank 2)
Indicator

The PCM has detected an incorrect voltage reading or waveform from the camshaft position sensor circuit for camshaft sensor “B” in engine bank 2. The camshaft position sensor is a stationary electro-magnetic sensor that works in conjunction with teeth or notches on the camshaft. The teeth or notches on the camshaft interrupt the sensor’s magnetic field (as perceived by the PCM) to input camshaft position data. This data is used in calculating fuel delivery and ignition timing.
Code Set Parameters

Deviations in system reference voltage, that exceed 10-percent of the manufacturer’s specified reference value may cause a code to be stored and a malfunction indicator lamp to be illuminated. These deviations are perceived by the PCM as incorrect camshaft position. Some vehicles will store a code and illuminate a service engine soon lamp on the first drive cycle and others require multiple drive cycles (usually three) for a service engine soon lamp to be illuminated. Nevertheless, a code should be stored on the same drive cycle in which the initial failure has occurred.
Symptoms

Some symptoms that accompany this code may include delayed engine starting, a rough idling engine, choppy or hesitant acceleration, a no start condition, or an overall lack of engine performance.
Common Causes

The most common cause of this code is related to oil (or other engine fluids) that have leaked onto sensors, wiring, or electrical connectors. This typically causes grounded, broken, or shorted wiring, along with loose or shorted electrical connectors. In some cases fluid contamination has also caused camshaft sensors to go bad. Some vehicles will store a camshaft position sensor circuit code if the crankshaft sensor goes bad. If one or the other is found to be faulty; it is recommended that camshaft and crankshaft sensors be replaced as a set. PCM failure is also possible but rarely occurs.
Common Misdiagnosis

My most frustrating misdiagnosis comes from a faulty replacement sensor. OEM quality components fail far less frequently than “bargain basement” parts. Just because something is dirt cheap doesn’t mean that it is a bargain. This code pertains to the entire camshaft position sensor circuit. Do not condemn the sensor before performing a thorough diagnosis of the entire system.
Diagnosis

The camshaft position sensor is an electro-magnetic sensor that interacts with a metal reluctor ring (or gear) on one end or the other of the camshaft
Engines that utilize multiple camshafts (dual-overhead cam engines) are equipped with multiple camshaft position sensors
As the reluctor passes by the sensor, a precisely placed hole or gap in the teeth interrupts the waveform pattern sent by the sensor to the PCM
This interruption correlates with an ignition timing reference value that is programmed into the PCM
Variations from the manufacturer’s reference timing value (seen as voltage waveforms) will cause a code to be stored and possibly a malfunction indicator lamp to be illuminated. Several specialty tools will be required to diagnose this code successfully
They include a scanner, a digital volt/ohmmeter, and possibly an oscilloscope. Begin with a visual inspection of all wiring and connectors
Repair or replace damaged, disconnected, shorted, or corroded wiring, connectors, and components as necessary
Always retest the system after repairs are completed to ensure success. If all system wiring, connectors, and components (Including fuses) appear to be in normal working order, connect the scanner (or code reader) to the diagnostic connector and record all stored codes and freeze frame data
This information can be extremely helpful in diagnosing intermittent conditions that may have contributed to this code being stored
Continue by clearing the code and operating the vehicle to see if it returns
This will help to determine whether or not the malfunction is intermittent
After the codes are cleared, test drive the vehicle to see if the code returns
If the code fails to immediately return, you may have an intermittent condition
Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made
In the event of an intermittent condition, you may also utilize the oscilloscope to monitor waveforms created by the distributor, camshaft, and/or crankshaft sensor/s, while looking for glitches or other inconsistencies. Suspect areas of system circuitry that are contaminated with oil, antifreeze, or power steering fluid that has leaked from the engine
If wiring with missing or distorted insulation is found, repair or replace it as necessary. If no obvious system circuitry problems are discovered, perform a resistance test at the camshaft position sensor and a voltage test on the sensor connector
Using your digital volt/ohmmeter test reference voltage at the camshaft position sensor and compare your findings with the manufacturer’s specified reference voltage
If system reference voltage readings are in line with specified values (or if sensor resistance values do not coincide), replace the camshaft sensor and crankshaft sensor. If system voltage readings do not coincide with manufacturer’s specified reference figures, check system continuity using your digital volt/ohmmeter
Use caution when checking resistance values in wiring that is connected to the PCM
For best results, disconnect the electrical connector from the PCM prior to using an ohmmeter on the harness side of the circuit
Remember that PCM failure is possible but very rare.

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Thank you for the info. Off to the dealer it goes

 

The sensor was replaced but now it is sluggish at about 4K. I read on another forum it may be the alternator or battery. Any suggestions??

 

You take it back to them and say "it ain't right."

As far as the alternator/battery thing, that's easy. You get one of these:

http://www.harborfreight.com/12-volt...ter-66842.html

Start the car, let it idle for a little bit. After a bit, the 'Battery' side should be completely lit, and the 'Alternator' side should be yellow and green, but not red.

If it is *anything* other than that, then you have an issue. And it's best to replace the Motorcrap batteries on these Mustangs... but if it's in warranty, go ahead and get the battery.

Of course, they'll just want to hold it until they figure out the battery/alternator thing themselves, which is a nice and extended test... or so they say. This little gizmo pretty much will show you the issue in 20 seconds. I've sometimes left it in the power plug on the dash just to see what it does when I was having issues, and found out exactly what it was (Alternator. Diodes were iffy, and it would be fine... then it'd just quit charging for a few seconds. Very strange, that.)

Past that, well, it's a pretty basic system, just overly complicated with sensors. Fuel in, air in, spark, explodytime, exhaust gases out, repeat a whole bunch. If any of that is insufficient, or there's another bad sensor, then the computer *will* have the codes in there.

If there aren't any codes, then the issue is a restriction. Fuel filter, air filter, exhaust. Pretty much it.

In the case of exhaust, the scary bit will be if the cats got burnt up when the bad camshaft sensor was happening, causing an incomplete burn, and fuel to exit the cylinder(s). That will burn in the very hot catalytic converter and cause this:

https://i.ytimg.com/vi/IL3enwh1aaE/maxresdefault.jpg

Which will then cause the exhaust to not flow, and choke up the car.

The last item it could be is it needs a tune up. How many miles? If a lot, maybe it's time for new spark plugs.

I'm sure others will chime in. Good luck to ya!

 

Thank you. It just got new plugs 1 month ago.

 

What kind of plugs did you use? The reason I ask is that the more high tech these cars become the more fickle plugs become. Recently I installed the high end Bosch plugs into a BMW, and the car ran like crap above 4000 RPM. I read the boards and everyone said to try NGK plugs. I installed the a problem solved. Also recently I installed Automate XP's into an Audi. I had the same issue except this time everyone said to install the top of the line Bosch plug and again problem solved. This has happened to me now on multiple occasions and these were just two examples of frustration due to the kernel being blown out by compression, etc. At any rate, I know the plugs are new but you may want to revisit them and tell the group which plugs you installed.

 

I had the dealer install the factory plugs