Something wrong with my EF Falcon - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

FlknTuff · 10-20-2005, 03:03

Hi everyone,

I was wondering if anyone could help me with this problem that I'm having with my car.

Today while driving my car I noticed that, as soon as it reached 60 km/h, the speedo needle dropped suddenly and then came back again. Few seconds later, the transmission suddenly downshifted to third gear and then shifted back to fourth again. This kept happening for the next half an hour and then went back to normal.

I suspect a faulty speed sensor but I'm not sure. I will take the car to a mechanic eventually, but I thought maybe someone here had a similar problem or might be able to point me in the right direction so that I can fix it myself.

Any help would be greatly appreciated.

Regards,
Alex

jas24zzk · 10-20-2005, 07:03

G'day,
upon reading the first part of your post, i thought...in order... loose tranny cable, Speedo unit, speed sensor.

Then you mentioned, the odd behaviour of the trannny.

Start by checking ALL terminals on your battery. This area is critical! every terminal and connection here has to be SPOTLESS!

I once had my tranny go into limp mode (locked in third) problem was simply a dirty terminal at the battery.

Failing this, it still sounds like an electrical fault...see an auto elec

Cheers
Jas

smally351 · 10-21-2005, 01:12

Sounds like a faulty speedo transducer to me, or even the drive or driven gears for the transducer. When the PCM loses the speedo input signal it will go into limp mode and 3rd gear is all you will get with drive selected. A simple PCM fault code check will probably reveal a code relating to loss of vehicle speed input in the memory codes.

FlknTuff · 10-21-2005, 01:38

Quote:

Originally Posted by smally351

Sounds like a faulty speedo transducer to me, or even the drive or driven gears for the transducer. When the PCM loses the speedo input signal it will go into limp mode and 3rd gear is all you will get with drive selected. A simple PCM fault code check will probably reveal a code relating to loss of vehicle speed input in the memory codes.

Would you be able to tell me where the speedo transducer is located and how to do a PCM fault code check?

smally351 · 10-21-2005, 09:14

The transducer is bolted to the extension housing on the rear of the transmission RHS.
A scan tool is the best way to extracr codes, but Im sure there are ways of doing this with bridge wires and an LED test light, search the forum for threads on this.

Fed · 10-21-2005, 17:31

Economy mode converter lockup?
If the car is 'new' to you and your are not real bright (no offense intended), this could easily be mistaken for a gear change?

LTDHO · 10-23-2005, 17:56

My LTD did it once. It was only low on fluid.