I have 2002 caravan transmission will not shift replaced both speed sensors no luck but after replacing input sensor the speedo, tach, blinks, hazard will not work please help
have the same problem?
Friday, January 13th, 2012 AT 11:26 PM
What led you to those sensors? Have you checked for fault codes? Does it start out in second gear right after you start the engine or does it go to second gear right after an up-shift?
Based on your other symptoms, it sounds like you have an electrical problem, not a computer-controlled transmission problem.
Saturday, January 14th, 2012 AT 2:25 AM
Talked to the guys at the local dodge dealership before taking it in for scan thought I give sensors a try just started yesterday on way to work the instruments were working but like I said I replaced input sensor took it for drive the cluster stopped working in the middle of the drive any help would be great thanks peter
Saturday, January 14th, 2012 AT 7:10 PM
Please take the time to put some punctuation in there. That huge sentence can be read many ways. Did you, "talked to the guys at the local dodge dealership before taking it in for scan", or "for scan thought I give sensors a try". It seems to me they checked for diagnostic fault codes and you replaced a sensor in response to that code. That is the logical step, but a defective sensor causes a fault code only about half of the time. Loose or corroded electrical connector pins or other wiring problems can set the same codes.
There are different types of codes related to one sensor too. The Transmission Computer constantly tests the electrical circuits. If there is a break in any wire going to a sensor, a code will be set related to that condition. Electrically the circuit could be fine, but if that sensor fails to produce a signal when it is expected, a different code will be set. The most common example of that is caused by metal chips sticking to the sensor's magnet and weakening the signal.
There could also be slippage in one of the clutch packs. That is detected by the speed discrepancy picked up by the input and output speed sensors. They are just reporting their information, and replacing a sensor isn't going to fix anything. A clue when that is what's happening is the system will reset each time you turn off the ignition switch, and it will start out in first gear the next time, up-shift to second at the normal time, then stay there or bang back into second gear after one of the next up-shifts. If it starts out in second gear as soon as you shift out of park, the problem is electrical-related including wiring and sensor problems. It can't be related to slippage in a clutch pack because they haven't even had time to engage yet.
If the instrument cluster, speedometer in particular, quit working well after the transmission problem started, you don't have speed sensor problems. You have two different problems that could very likely not be related. Those sensors have to work for the Transmission Computer, Engine Computer, Body Computer, and instrument cluster computer to work together to calculate road speed and display it. If the speedometer worked after the transmission acted up, the sensors were working.