My car went into "failsafe" mode and engine light came on. Took it to a mechanic and it was speed sensor malfunction, he replaced one and drove it around and it did the same thing. He replaced the other one and still did the same thing. Now he looked at electrical system and seemed fine, can't find the issue. Suggested to replace the instrument panel because speedometer would fluctuate from time to time. Would replacing the TCM possibly fix this? It just seems like something is shorting the sensors everytime he replaces them. Please help! I'm currently stationed in Germany and it's hard to find a mechanic who's knowledgeable in japanese cars.
P0720 OBD code / speed sensor malfunction on 2004 Mitsubishi Lancer
by puit2 in Tampa, FL on October 21, 2010
ANSWER by ZeeTech on October 21, 2010
I assume the tech installed the sensors to it's correct location. They can not be mixed up. If you post an e-mail, I can send a diagram about the correct locations. I'd check the continuity from the sensor's connector to the TCM, make sure the wiring is OK, also scope test the signals from the sensor to the TCM. Zee
ANSWER by mastertech6371 on October 21, 2010
instrument panel is not the issue. the signal is sent to the tcm from the sensor not the IP. metal in the transmission could be the issue as well. it may not allow the sensor to read correctly. you need a trans shop. by the way, sensors do not short and burn out. they are variable signal generators. you need someone else to look at your car. Roy