Chrysler Repair: Speedometer sometimes shows velocity zero, chrysler neon, neon 2

Question
Chrysler Neon 2.0 Standard Edition (Denmark)
Automatic transmission. Bought as new late 1996.
Problem: Speedometer periodically does not show correct velocity - in fact it shows something between zero and correct speed. Sometimes speedometer functions OK.
It seems as everything else on the panel is shown correctly (rounds-per-minute...)
My mechanic has cleaned the "multiplug" but it didn't solve the problem.

Question: Is it advisable just to buy a new cable or should something more be replaced?

It is a problem I just want to get solved as quick as possible.

Kind regards,
Ole Rønne
OLRON@dk.ibm.com

Answer
Hi Ole,
The speedometer is driven not by a cable, but by an electrical signal from the distance sensor which is a device that is geared into the output of the transaxle and pulses 8 times for each time the road wheel turn one revolution. It is possible that the speedometer head in the dash is flakey, but it is also possible that the distance sensor gear has been damaged, or that the electrical wire from the sensor to the speedo (and it is also needed by the engine controller so it is "split") is intermittant. If you have ever had to have the passenger side half-axle shaft removed to repair a cv-joint or cv-boot it may have been damaged in the course of that repair (blame the repairperson for that and maybe get them to pay for a new gear). The sensor must be removed if you attempt to pull the half-axle out of the transmission housing. You can look for the sensor, and remove it and inspect the condition of the gear. It is located behind the engine, low at the level of the half-shafts and it is sitting on top of the housing out of which the half-shafts protrude. It has a wire with a connector and a single bolt holds it in the housing.
You may be able to verify that the problem is not with the speedometer head if you can readout the fault codes stored by the engine controller and you find therein a code 15 which says the signal from the sensor is absent. To readout the codes, take your ignition key and turn the ignition switch on-off-on-off-on and leave it on (doing this with an elapsed time of no more than 5 seconds, where 'on' means the run position, not the start position). then watch the check engine light to begin to flash, pause, flash, etc. Count the number of flashes between pauses and make a mental note of the numbers (or write them down); the last set of flashes will be 5 in each set. Then group the numbers as they came out into pairs to form two-digit numbers which are the codes. The last code is 55 which means 'end of readout'. Then see what the other code numbers are, if any. Maybe a 15 will be the first code, and that way you know it is either the gear of the sensor or the wire (check the electrical disconnect plug to make sure it is tight and the contacts inside are clean, as well).
I am not certain whether the 96 has this self readout capability but i know the 95-earlier do. You can re-read the codes as often as needed to be sure you have them correct.
Let me know if you have any questions, and whether any thing interesting occurs.
Roland