1996 Dodge Caravan...Codes P0117 & P1493

My 96 caravan with a 3.8L engine and about 75,000 miles has displayed these codes and since the temp gauge doesnt work now I replaced the sensor but the problem remains. Also the radiator fans come on as soon as I start the van with or with out the A/C. Where the heck is the ambient battery sensor ??? The van runs fine … it has had a problem for quite some time it will just shut off … hot or cold…speed no factor… straight line or turning…but it will restart with no problem… I dont know if that is a factor… and no error code is retained… like it flushes the memory. I have searched the web and read and read I would take it to a dealer but I havent had many pleasant experiences there… seems they replace parts and if it doesnt fix it you still have bought the unneeded part. I would appreciate any help.

Also I cannot find the battery ambient air sensor…physically or in any wiring diagram ???

The p0117 is a CTS (Coolant Temp Sensor) code. This is most likely why your cooling fans constantly run. It could be a bad CTS, or the wiring to the CTS is bad. The P1493 (Batt ambient temp sensor) This is the first time I have seen one of these. I googled it and saw on a forum where the poster was told to check the battery tray under the battery for the sensor. Like I said, I have never heard of this before so maybe someone else who has will respond here.


The P1493 may be a phantom. I didn’t see a battery temperature sensor on two wiring diagrams.
The wiring diagrams show the engine coolant temperature sensor (ects) as having a voltage supply (5 volts?) on the black/light blue wire, and an output to the engine computer over a tan/black wire. There is no wire shown going to the instrument panel temperature gauge from the engine computer. There may be another engine coolant temperature sensor for the gauge.
The ects, fan relay, or an electrical short, may be causing the engine cooling fans to stay on. Replace or swap the fan relay.
For the sudden engine shutoffs, swap the fuel pump relay with the horn relay. Swap the ASD relay for another. Several of the relays are the same type in the relay box under the hood.
Tell us the results of the relay swaps/changes.

Thanks for the reply…

I replaced the temp sensor and compared the old and new resistances hot and cold and found both the same…
it is wierd that all this happened at one time.
it seems like there should be something in common about them but I have been unable to find a skematic with the battery ambient temp sensor…I pulled the batt out and looked around but I guess I will pull the tray out and see what I can see under the tray… sure would be nice to see it on a skematic…

P1493 is a manufacturer specific code. The various data bases on the internet say that for Chrysler, it is battery temperature sensor voltage too low (which I take to mean that the sensor is defunct). But 1996 was a long time ago and it was the first year that OBD2 was required and the chances of it being a computer bug or having some other meaning that never got documented are fairly high. These manufacturer codes are sometimes concocted by sticking a 1 in front of some related required code. In this case, that’d be likely be P0493 – fan overspeed.

Maybe if you fix the P0117 problem, the P1493 will go away. Keep in mind that many DTC codes don’t clear until no problem has been seen for some number of “drive cycles” and that the definition of a “drive cycle” varies from vehicle to vehicle.

Thanks for the reply,
The ects has one side to sensor ground and the other to the pcm on term 26 and I ohmed out the wires and all is okay. Someone suggested the batt temp sensor was under the batt tray so I took that out but I didnt see anything there… I know I cannot find it on any diagrams. So now I got pcm out and will probably order a rebuilt one.
I will try the other relay swaps when I get the temp gauge working.

Thanks for the reply,
It was suggested that the batt temp sensor was under the batt tray so I removed it but I havent found any sensor there. I ohmed out the wires for the ects and the wires have continuity up to the pcm. About the only thing left to try is the pcm…
One thing about it if I find the problem I will have instant feedback when the tremp gauge works LOL !!!