QuestionQUESTION: What does the computer code 1412 mean on a 1997 Plymouth Voyager mean? The cooling fans do not come on, but operate if hot wired.
Do I need a new computer?
ANSWER: Hi Charles,
Was that code obtained by the check engine light? If so, then it probably means a code 14 and a code 12 of the OBD-I fault code system. There is no 1412 code in the OBD-II system.
The 12 means the battery was disconnected recently (last 50-100 key cycles), while the 14 means that the manifold absolute pressure sensor signal voltage is outside the normal range. So I would check the wiring at that sensor. You didn't mention the engine so I can't give you more specifics than that. If the wiring is good then you may need a new sensor.
Let me know the engine size (L).
Roland
---------- FOLLOW-UP ----------
QUESTION: Since the code has nothing to do with the fans lets eliminate the code stuff and just deal with the fans. The car is a 97 Plymouth Voyager with a 4 cylinder engine. The fan relay was recently replaced because the mechanic thought that possibly the fans was not working due to a relay failure. The fans definitely work when hot-wired. Now he is suspecting the computer. Expensive! Is there the possibility that the engine temp sensor is faulty and where is that located? How is that tested? If that is replaced and the fans still fail to operate then what are the DIY drawbacks of replacing the computer?
AnswerHi Charles,
The coolant temp sensor is threaded into the thermostat housing and you can find that housing by following the top radiator hose back to the engine. It has an electrical plug on the tip (lift tab to release). Then when the system is colt the resistance between the 2 pins of the sensor with the plug removed should be around 3-4,000 ohms, and as the engine warms up the resistance should drop to around 1,000 ohms. If that doesn't happen then either the sensor is bad or there is air trapped in the housing. If the coolant was drained from the system when this problem began, then the problem may be due to air trapped in the thermostat housing. When refilling the system you should have removed the sensor and then refill until the fluid reaches the top of the opening in the housing, then install the sensor. You could drain off about a gallon of fluid for reuse, then remove the sensor, then refill system till level reached to the hole top, then install the sensor, then finish refilling. You could also check the wire connection between the plug and the computer (tan/black wire to pin 28, black/light blue to pin 43). Only after all that is verified would I replace the computer, and ideally there should be some sort of fault code that corroborates that possibility.
Roland
