Question
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Followup To
Question -
I own a 1996 Dodge Caravan sports Edition with a 3.3L V6 engine. It has 270,000 miles on it.
The MIL turned on and using my OTC Scanner it reports that the (1) ECT sensor voltage is too low and (2) the Battery temperature sensor voltage is too low. Under these conditions, the Temperature gage is not functioning and the radiator fans turn on whenever I turn on the ignition. Mitchell's repair guide says that if the scanner reports that the battery sensor temperature is too low with a run count of zero, the PCM should be replaced.
1. I do not know the meaning of "run count of zero"
2.Does the replacement of the PCM take priority over the problem of ECT sensor which I already replaced?
The PCM is quite expensive and I want to be sure it really needs replacement.
Thanks for your HELP. Max
Answer -
Hi,
Yes it does tkae precidence over the ECM. The DTCM controls most of the functions of the entilr trive train. The ECM only controls the ignition system. It akso gets it's information from the DTCM.
Cowboy 1104
Thank you so much for your reply. I just would like to clarify the terms we have used so far. The terms I used are from Haynes Repair Manual for Dodge Caravan.
ECT= Engine Coolant Temperature Sensor
PCM= Powertrain Control Module which is the computer that processes inputs from Engine Coolant Temperature Sensor, Camshaft position sensor, Intake air temperature sensor, Crankshaft position sensor, Heated Oxygen sensor, etc. The PCM regulates the ignition system using inputs from these sensors (Haynes Automotive Repair Manual)
In your reply does “ECM” refer to ECT and “DTCM” refer to PCM? It would seem that way but I want to be sure. In some other manuals ECM has been used interchangeably with ECU (Electronic Control Unit) and PCM. Haynes also uses TCM (Transmission Control Module.), which electronically controls the transmission.
With this clarification, I would like to ask further:
Are the two conditions 1) Engine Coolant Temperature Sensor voltage too low, and 2) Battery Temperature Sensor voltage too low independent of each other, or is condition 1) due to condition 2)? If they are independent of each other, condition 1 may continue even after I replace the PCM. I need to know so that when condition 1 continues as a problem, I will not conclude that the new PCM is defective. As I mentioned earlier, I already replaced the Engine Coolant Temperature Sensor but condition 1) still registers in my scanner.
Once again, thank you so much. I really appreciate the fact that you are out there just to help others like me.
Max
AnswerHi,
You can go to the public library and check out a Chilton's Repair Manual. This should tell you which pins to ohm out and what the readings should be. So get the book and take the Drive Trian Module (located on the Right front of the fender well) cable loose and ohm between the pins refered to in the manual. This is prior to replacing the module. If all the pins ohm out to the proper output this will either eleminate the (DTCM) or pin point the problem.
Cowboy 12104
