Tip & How-To about Ford F

Truck will not start, everything else seems fine

If the truck will not start, and it is an automatic, wiggle your shifter up and down a bit, you may have a faulty MLPS sensor, which causes the truck to think it is not in park or neutral, which will not allow the truck to start. If the truck does not start after that, you may need to troubleshoot the truck some more

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2000 grand marquis shifter loos

your car has what is referred to as a Manual Lever Position Sensor (MLPS) located on the driver side of the trans-it is connected by cable to your shifter, and it is how you control the trans. It is mechanical AND electronic, with the position of the pawl and the electrical connector very important. It is not an expensive part and it not very difficult to replace held in place by 2 bolts. It is important that it be installed with the pawl and the shifter in neutral for alignment purposes. The part is sometimes referred to as a 'neutral saftey switch' and generic parts stores-around $45 or less total.

Nov 16, 2011 | Cars & Trucks

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what is MLPS in automatic transmission

The MLPS or manual lever position sensor is one of the vitally important inputs to the transmission control unit (TCU) of a vehicle with modern computerized automatic transmission. Every car made in the last 50 years has a switch similar to an MLPS. The names range from MLPS, to inhibitor switch to neutral safety switch.

Originally called a neutral safety switch when introduced to the automotive field because it's only duties were to make sure the car only start in neutral and park, and to activate the reverse lights when you shift into reverse.

As automatic transmissions became more technically advanced the MLPS duties increased. Now the MLPS or inhibitor switch is a key input to the TCM and ECM on every modern car I can think of. In fact, the switch, whatever name you call it has a great deal to do with controlling what gear your automatic transmission is in and how it shifts, and when the torque converter locks up, as well as it's original duties.

In most cases the switch is located on the side of the transmission, essentially hooked to the shift lever in the car. That way when you move the lever, itâ moves the switch to the appropriate gear range. some cars have a remote mounted switch, however the responsibility remains the same.
On transmissions with a side mounted switch, GotTransmissions.com often provides a new switch with their rebuilt transmissions where failure's are more prevalent. If it is not included with the transmission, it is a good idea to scan the car before any transmission work is done to make sure that did not cause the problem. At my shop, we almost always changed every one when we did a rebuild on a transmission. Either way, I would advise putting a new factory MLPS on your car if you do have to exchange a worn out transmission for a rebuilt transmission, unless it is cost prohibitive.
Most of the time when an MLPS goes bad, you will know you have something wrong with it. This is the time toâ have it checked by a qualified transmission mechanic at a competent transmission shop.

Many folks who own affordable hand held code readers can find out what the problem is before hand. In many cases if you are mechanically handy you can change it yourself. If you choose to take that route. don't forget to clear the code and re-drive the vehicle and recheck to make sure you cured the problem.

These particular switches are on the outside of the car as we mentioned earlier and are exposed to the road elements. Therefore causing a hi rate of failure. Geographically speaking, problems can occur from salt being used to melt snow in the north to water damage from a heavy rain.
Don't forget to properly maintain your transmission on a regular basis. Feel free to sign up for our GotTransmissions.com blog for free. You may find more money saving and drive-ability tips in your mailbox regularly.

Hope that helps

Jan 06, 2011 | 1998 Chevrolet Venture Cargo

1 Answer

I am trying to find the fuse that lights up my shifter so I can see what gear I am in.

the power for the ilumination comes from the mlps switch on the side of transmission. If no ilumination suspect bad sensor.

Jan 06, 2011 | 2005 Ford F-150

1 Answer

Car will not start. I wiggled the shifter around

You may have gotten a bad switch otherwise just check to make sure it is adjusted properley. If you loosen the bolts there is about a half inch of adjustment on those. The turn signal is a ground issue most likely. You gotta chase down the wires to figure that one out. It may also be a faulty turn signal switch but not very likely

Mar 11, 2010 | 1998 Buick Regal

1 Answer

1995 bmw 318i will not start once the car is up to operating tempature, once turned off it seems that it must cool down to be able to start again.

Possible causes: Fuel pump relay, Pump, Fuel Filter, Regulator, Crank Shaft Sensor, Camshaft Sensor, Loos Connection(try to wiggle the wiring harness and observe). or faulty Ignation Switch.

Observe if the engine will lack of power first before to shut off, if this is the scenario it could be a fuel pump relay or pump. I suggest you to monitor the fuel pressure first or try to swap fuel pump relay to other as long as same color or figure and observe it.

If the senario is sudden cut off, it coud be a faulty cranck shaft sensor. a faulty cranck shaft sensor is easy to determine using tachometer while cranking, if the sensor is faulty the tachometer will not move or rise even a little bit if it's good it will rise a bit while cranking the engine.

Check fuel pump when the problem occur, try to ignition ON/Off and listen to fuel pump motor noise from underneath (close to rear right side tire), the pump will operates for aprox 5 sec. everytime you turned ON the ignition switch. and if you can't hear noise then you have to focus to fuel system.

Jan 09, 2010 | 1997 BMW 328

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