Auto Shutdown Fuse Popping

Hellloo again,
another problem occured with my heep.

i have a 1996 XJ, 4.0L, Aw-4 tranny.

i was playing in a mud puddle today, when i romped on the gas the jeep died. after examining through everything, i found my auto shutdown fuse was popped. it only had a 25a in there -.- so i replaced it with what the manufacturer called for, which is a 30a. that one popped 30 seconds later. can somebody help me on where to start on diagnosing this issue, for i have never owned a vehicle with an ASD circuit.

Many thanks

fyi, drives GREAT with a jumper in it... not safe i know.

so i bought new fuses for it, and switched the fuel pump & ASD relays (which i do not think had anything to do with it) and the problems went away. i stopped on a hill and when i went to go leave i gave it harder throttle and the vehicle died, burning the 30A ASD fuse. i replaced it... fried it again. i checked all the wiring to the distributor, coil pack, fuel pump, and even all the grounds and everything looks the same. anybody know how to help vehicle still currently on side of the road, that was the longest 10 mile walk ever -.-

Thanks !

You are going to need a wiring diagram, a meter, and the ability to use both.........

These type of electrical gremlins can sometimes be a bugger to find.

I had an o2 sensor kiss the borla and short out the asd before(it never blew the fuse though). Maybe caked up mud or something kicked up and tore a wire or exposed it to chassis metal?

gradon said:

I had an o2 sensor kiss the borla and short out the asd before(it never blew the fuse though). Maybe caked up mud or something kicked up and tore a wire or exposed it to chassis metal?

Click to expand...

Sounds like a good clue. Heavy foot on the gas would cause more torque, and could have caused a wire to move just enough to re-short to ground.

I don't think my Renix has an ASD relay or fuse, but when the O2 sensor wires got too close to my front driveshaft, it smoked the fuse link wire and dropped my dash gauge volt meter to 8 volts!!! Pulling the O2 sensor heater relay got me home, which was a 200 mile walk I avoided, LOL.

@Gradon & @Ecomike

Thank you so much. It indeed was the o2 sesnor wire grounding out.appears my driveshaft split them open slightly.

thank you so much for contributing to the community!

Wow....great input from Gradon and Ecomike and a very quick resolve here.

Sometimes we get lucky, LOL!:laugh3:

if anybody has ever done google searches for this issue, you will find 1 post, on 5 different threads of the same guy trying to remove his asd circuit. can anybody explain what is involved in the circuit as well as how else would it go defective for anybody else with this issue at a later date?

I don't know what all is on the asd circuit but do know that the pcm provides 12v for the heaters on the o2 sensors and 5v for the other sensors(most on the tb/intake manifold). Usually it's a shorted crank sensor that causes the asd to trip, and the symptoms are crank, but no start, and sometimes "no bus" on the 97-01s. My shorted o2 sensor harness killed my pcm, so for a while I was using a 97 pcm in my 96.

Glad you already got it figured out! Same exact thing happened to me in fall '10.

The asd on a 96 runs the o2 heaters, the alt field coil, the ignition coil, the injectors, the ecu, and (iirc) the fuel pump. Other years are probably similar.

The ECU provides 5v to the sensors, but without 12v to the ECU it obviously won't do so. When the o2 wiring gets worn or melted the 12v heater power can short to the signal wiring which will burn out the ECU if you are unlucky.

The upstream o2 sensor wiring is supposed to be routed around the back of the ps pump where it bolts to the manifold (right under the fuel rail supply lines), and also held to the lower front driver side of the block by the oil pan to prevent it from melting onto the header. Routing it around the front of the manifold and down between the manifold and the serpentine belt is a common mistake that can easily get it melted by the #1 exhaust runner, similarly the downstream o2 wiring (on 96 and later) can easily come unclipped from the body and fall onto the driveshaft.

Renix doesn't have an ASD relay per se, but it does have a B+ latch relay which is mostly analogous.

Great info there Kastein! Isn't the ASD relay also there to prevent fires in case of a severe accident (I guess by blowing the load fuse?)? Or is that a separate relay, anti rollover xx??

I'm not sure what you mean by blowing the load fuse, but the ASD basically powers the whole drivetrain, so I guess it could shut the engine down in a bad accident. I'm not sure if that was ever implemented, will have to check the schematics when I get home from the midwest.

kastein said:

I'm not sure what you mean by blowing the load fuse, but the ASD basically powers the whole drivetrain, so I guess it could shut the engine down in a bad accident. I'm not sure if that was ever implemented, will have to check the schematics when I get home from the midwest.

Click to expand...

I was referring to the fuse the OP was blowing that powers the ASD relay and the O2 sensor heater. If I understand it, the ASD relay shut down when the fuse blew, and the O2 heater wire short blew the fuse, thus shutting down the relay, all spark sources that could start a fire?

Well the fuse and relay contacts are in series, so yeah, the fuse shuts off everything the relay protects.

Without looking at a schematic, I assume the fuse provides 12 volts to the relay, correct? What operates the ASD relay?