The trouble code is P0303 on my 2003 LS V8. When engine on and gear in parking or neutral position engine working isn't optimal, it seems it hasn't enough rpms and the car is shaking a little. also the engine has lost a power. When cleaning the code the engine begins to work fine, but after two or three day driving the check engine light is on again. I've changed the ignition coil of the 3rd cylinder and the spark plugs too, but the same happens.

Possible causes Faulty Park/Neutral Position Switch Misadjusted Park/Neutral Position Switch Park/Neutral Position Switch harness is open or shorted Park/Neutral Position Switch circuit poor electrical connection What does this mean? When is the code detected? The transmission range switch detects the selector lever position and sends a signal to the TCM. Possible symptoms Engine Light ON (or Service Engine Soon Warning Light) P0705 MERCEDES-BENZ Description The park/neutral position (PNP) switch includes a transmission range switch. The transmission range switch detects the selector lever position when the shift lever is in the N or P shift position and sends a signal to the Transmission Control Module (TCM).

on most cars, you need to change the neutral safety switch. this car has a neutral parking position sensor, you can find it for v6 not v8, it also fits a saab 9-3. it is the same thing, a different style. however, check the transmission fluid level and troublecodes for p07xxs. reset the code and use the transmission dipstick by dorman add lucas auto trans fluid, not stop slip to the fill line. most of the time it's not the solenoid, but the auto trans plate, overfilling the fluid can cause it to trigger a check engine light, and the fluid leaking onto it can cause it to be permanently damaged, it's more than $400 for the part. lucas works in the 722.xx transmissions, most , all, clks 99-2002, just make sure the tranny model isn't a 238. i like it better than atf 134. However, these parts are very heat sensitive. fill the trans fluid, reset the troublecodes, do a general motos drive cycle from obdii.com if it doesn't drive good after four times, change the neutral safety switch. :)

Trouble shooting a misfire, Code P0300, P0301 ... - YouTube

? 23:39
www.youtube.com/watch?v=G_grIaTgdRI
Oct 26, 2013 - Uploaded by Robert DIY For the new play by play misfire video click here: ... Trouble shooting a misfire, Code P0300, P0301, P0302, P0303, P0304, P0305, P0306, ...

Trouble Code: P1391

CKP Or CMP Sensor Signal Intermittent
Possible Causes:


Camshaft Sensor is not installed properly . Engine valve timing is not within specifications. Perform a CKP and CMP Sensor relearn with the scan tool . Tone wheel or pulse ring is damaged .

Trouble Code: P1899

A/T Park Neutral Switch Stuck in Park Position or In Gear
Possible Causes:


P/N switch signal circuit is open between the switch and PCM . P/N switch signal circuit is shorted to Sensor or chassis ground. P/N switch ground circuit is open (at the switch mounting point) . P/N switch is stuck in P/N position, or stuck in Drive position . P/N switch is damaged or has failed. PCM has failed .Here is what is listed for these codes.

- Open or short park/neutral position switch circuit
- Poor park/neutral position switch circuit connection
- Misadjusted park/neutral position switch
- Park/neutral position switch may be faulty

Code P0705 - Transmisson Range Sensor Circuit (PRNDL Input)
The transmission range switch detects the selector lever position and sends a signal to the TCM.

The park/neutral position (PNP) switch includes a transmission range switch. The transmission range switch detects the selector lever position when the shift lever is in the N or P shift position and sends a signal to the Transmission Control Module (TCM).

Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)

Possible causes
- Open or short park/neutral position switch circuit
- Poor park/neutral position switch circuit connection
- Misadjusted park/neutral position switch
- Park/neutral position switch may be faulty

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Disconnect and plug the vacuum hoses to the EGR Valve
and drive a few days.

I think your getting random misfires and the #3 is not
the issue,as you installed a new coil.

The PO300 codes on a L/S are not always an indication
of a bad coil on that code. I have had to walk a new coil
until I got the bad one.

Spray the MAF with CRC MAF Cleaner

If the O2 Sensors are around 100,000 replace
the front two. Don't use universal ones. You can
order from NAPA,the connectors may be a different
color and they give you 5" too much wire but are the
OEM NGK Sensors.

Meter the TPS Sensor and If you have an
oscilloscope use that. KOEO work throttle plate
by hand

if your parked on a hill try rocking (pushing)the car back and forth wile tring to shift it out of park

It is an integral rev limiter for park and neutral.

Sounds like the PNP switch or the Park/Neutral switch is out of line (adjustment). There is very much information about this on the internet.

Just today I was called by my garage because the mechanic could not start the car. I had my 1993 960 in for freon (134). Over the phone he said the starter would engage but no start. He was about to recommend a new fuel pump because no fuel was reaching the engine. So I said wait. I went down and while he was not looking I did the shifting routine of: brake depressed, key on, move shifter from Park through all the gears several time, then key off. After this I could start the engine and drive off. On the transmission is a PNP inhibitor switch and a Park/ Neutral sensor switch that cause no start and no shift situations. Oh yes, I did not bother to tell him what I did! He spent six hours trouble-shooting and would have charged me.

My next project is to wire around these trouble makers. I always drive in "E" and I do not care if it will start in all positions.

William White