I have a 2001 Focus with the same problem. I went on the internet and found that MANY people with a Focus for the past 5 years have this same problem. One site I went to said this:
"I'm post #60 and was just reviewing the site as I was reading the service manual. Might be the transimssion oil temperature sensor. If the sensor has failed in some odd way, my guess is that this could happen. This sensor is located in the tranny oil pan, under the transmission filter. The sensor can be checked by use of an ohm meter. See below...
This is out of the manual:
Transmission fluid temperature (TFT) sensor
The TFT sensor is located on the internal wiring harness to the solenoid valves in the fluid pan.
It is a resistor and measures the transmission fluid temperature.
The transmission fluid temperature is used by the PCM for the following functions:
Applying the torque converter clutch is not permitted until the transmission fluid reaches a certain temperature, engagement of 4th gear is prevented in extreme sub-zero temperatures until the normal operating temperature is reached,
if the transmission fluid temperature is excessive, a pre-set fixed shift curve is selected and the torque converter lock-up clutch is closed in "2", "3" and "4"; of the transmission warning indicator is activated.
Resistance between transaxle vehicle harness connector pin 5 (component side, transaxle internal harness), and transaxle vehicle harness connector pin 4 (component side, transaxle internal harness).
Resistance should be approximately in the following ranges:
-20 ? C (-4 ? F) - 236Kohms - 317Kohms
0 ? C (32 ? F) - 83.2Kohms - 107Kohms
20 ? C (68 ? F) - 33.5Kohms - 41.2Kohms
40 ? C (104 ? F) - 14.6Kohms - 17.6Kohms
60 ? C (140 ? F) - 7.08Kohms - 8.01Kohms
80 ? C (176 ? F) - 3.61Kohms - 4.06Kohms
100 ? C (212 ? F) - 1.96Kohms - 2.20Kohms
120 ? C (248 ? F) - 1.13Kohms - 1.25Kohms
130 ? C (266 ? F) - 0.87Kohms - 0.96Kohms
Pin numbers as looking at the connector on top of tranny with lock tab on top:
1 2 3
4 5 6
7 8 9
Good luck, let us know what happens,
Any comments on this possibility? Manofallseasons