Can a negative terminal of a battery touching the body of the car cause a short?

Question

Today my car died while driving it and would not turn over for a good 10 mins finally it came to and got it home. I Gave it a scan and was told it's the o2 sensor and after google around it says it can be caused by a short. I checked under the hood and the negative battery terminal was touching the body of the car. (I replaced battery the day before) I moved it out of the way and the car started without a problem.

My question is could that have have been the cause of the problem? To the extent of my knowledge I figured a ground connected to the body of car wouldn't cause a short but maybe I'm wrong.

Answer 1

That is where the negative cable attaches, to the body so it touching wouldn't cause an issue.

An o2 with a short is an internal short of the sensor, not of the cars battery. Its also extremely rare that an o2 fault can cause a stall or no crank condition.

It sounds like you have/had a bad connection at the battery and that is the cause of your problems with the stall and not cranking so moving the cable made a better connection but you still need to correct it.

Answer 2

A “ short “ related to the O2 sensor could lower the voltage at the sensor because the flow of electricity is “short circuited” to someplace else, and not the sensor.

A badconnection, corroded connection or just low voltage in general could look the same (lower voltage due to resistance) and generate a fault. Wiggling corroded (loose) connections can temporarily scrape off corrosion to restore a little voltage. Wiggling connection’s is a tried and true diagnostic technique using a light or meter to see if it changes anything.

Answer 3

The positive terminal should never touch the body of the car, or anything grounded. In theory, the negative terminal touching the body shouldn't cause an issue. I've added ground cables to multiple cars running a cable from the battery direct to the chassis with no ill effects. That doesn't mean you don't have something weird going on, obviously it seems to have worked for you to move the battery, but I feel that would generally be an unlikely cause.

Answer 4

As far as I know it shouldn't, but there's always the chance of something weird going on.

The negative terminal in most vehicles is connected to the body so that fewer cables are required (one run from the positive to a device, then the device is connected to the body to complete the circuit instead of running a negative wire back to the battery).

There are some positive chassis vehicles, where the majority of the wires are negative and the positive is connected to the body. I may be wrong, but I believe no new reverse polarity cars have been built since the 70's.

If there was a short, there may be black marks or there may have been sparks where the battery was touching the body. However, the body is normally painted so it shouldn't be making a circuit.

As a wild guess, there may be an issue with the wiring on / near the battery and when you moved the battery, the short was disconnected. Brittle or cracked wire insulation may be the cause (and hard to spot) or a stray strand sticking out of poorly terminated cables can cause intermittant shorts.

What make and model car do you have?

Comments

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