Fuse keeps blowing, P0705 (Transmission Range Sensor Circuit Malfunction)

[Jonas]

(2009 Pontiac Vibe GT)
Hi all. I had this problem before where a fuse blew along with a P0705 code. I replaced the fuse, and everything was fine for several months, if not a year. Today, the fuse blew again, but the replacement fuse blew as soon as I started the car (two fuses, both blew immediately.) The fuse in question is pictured.
In addition to the code, my airbag light came on, and the turn signals stopped working (maybe other random malfunctions, I'm not sure.) I've also pictured a part that may or may not be the problem, but I can't find out what it's called.
I recently replaced my radiator, which required a lot of banging around by the tranny, but that was about a month ago. I couldn't find any loose connections or anything out of place. Any ideas?

Thanks in advance,
Jonas

 

[GSCJR]

That's the neutral safety switch in the photo. Check the condition of the wiring going though the conduit for the rear hatch, that's where I would start.

 

[Jonas]

That's the neutral safety switch in the photo. Check the condition of the wiring going though the conduit for the rear hatch, that's where I would start.

The rear hatch of the car? Like, the hatchback door?

 

[GSCJR]

Yes, the wires may be chafed from the repeated opening and closing (defogger and tail light circuits?)

 

[Jonas]

I couldn't find anything. This happened a year ago and replacing the fuse fixed it. I should add that the fuse blows as soon as I turn the car on, before I even start the engine.

 

[samven]

Thats the thing with a short. The wire could be worn and touch a ground like the chassis but move slightly and remove the short. Then vibration or opening a door could push the wire back against the ground and as soon as you put power to the circuit the fuse goes. It can be difficult to find because in the process of moving harnesses to look for chaffed wires you clear the problem temporarily. My son had an issue with a BMW Rear Wheel Sensor that the dealer kept throwing parts at and the problem kept coming back. An indy finally found where a mouse had chewed into the wiring harness about 5 ft from the wheel sensor along the frame. After that no more issues and a lot of BMW parts that were not needed.

 

[Jonas]

I'm working on the fact that the same fuse blew last year, but was fine after I replaced it. Before it first blew, I wrongly replaced the alternator, then removed it and re-installed the old one. Fast-forward to a month ago, I had to remove the alternator again to replace the water pump. The crankshaft position sensor wire runs in between the water pump and alternator, but, if it was shorting out, would the engine even run? Since the fuse in question affects the charging system (among other things) would it be more likely there is a short around the alternator area, or is that a red herring? I'd love to at least narrow it down.

 

[ripcord]

It is impossible to overstate the importance of careful visual inspection. Looking at the last area you worked in is always a good idea.

 

[samven]

Follow all those harnesses in the area you were in and make sure none are pinched and look for chaffed spots on the outer wraps or places that look flatter than the rest of the harness. You may find that after you move everything around the fuse does not blow but that does not mean its fixed, its just waiting for you to hit a big bump to reappear.

 

[Jonas]

The crankshaft position sensor wire looks kinda rough, but the engine still runs, so that wouldn't be the problem, right? Also, is there any significance to the fact that today it blew while driving, then shortly after starting, then just when turning the key (before starting)?

 

[Jonas]

I replaced the fuse this morning, and it blew again, but not until shortly after the engine was started. Does that tell you anything? I will say I applied some liquid tape to exposed wires at the crank position sensor connector yesterday, but I can't remember if that was before or after the short happened. I also disconnected and reconnected it this morning, but I doubt that's related since there were no codes for it and the engine starts and runs.

 

[clinebarger]

I'll attempt to help....It's likely shorted under the hood from looking at the diagram, I would break the system apart to aid in diagnostics.

There's a connector under the hood, Drivers side (Looks to be under or inside the engine compartment fuse box?)
Connector X101, Pin 5, Dark Green Wire. (#6 in the diagram)

I would de-pin the wire out of the connector on the ENGINE side of the harness, Twist the stripped end of a length of wire to the terminal of the wire you de-pinned & tape over in with some electrical tape.
Route the jumper wire out of the fuse box & plug back in everything you disconnected.

You have now separated the circuit into 2 parts.....The Alternator Regulator & the Neutral Safety Switch is now separated from everything else on the 10A fuse in the IP fuse box (Flasher, Defog relay, Security Lamp....etc)

The next step can be done a few different ways.
1. Install a good 10A fuse & start the vehicle & see if the fuse blows?
2.Install a inline fuse on the jumper & connect in to the battery positive....Use a 5A or 7.5A as the only real current carrying component now is the reverse lights (Which aren't on in Park).
3. Perform both steps.

 

[clinebarger]

It is impossible to overstate the importance of careful visual inspection. Looking at the last area you worked in is always a good idea.

Can't overstate it either!!!, I should of said break the circuit apart IF visual inspection is a dead end.

 

[D60]

A crude approach is pull the fuse. With key on one side should be hot and the other grounded IF it's in a state where it's blowing immediately.

If you have a PowerProbe (and if you don't, I recommend ordering one) stick it in the grounded side and leave the audio alarm on. Start moving wires at suspect places and if you can make the tone stop, you're on to something.

You could also do this with a test light but you'd need visual on the light at all times, and it's arguably easier for our senses to detect a blip in a constant tone than a flicker of a bulb.

This approach is not guaranteed to produce results depending upon where the problem is and how it's shorting, but it's quick and easy to start (and kinda fun)

 

[Hootbro]

Does it blow a fuse disconnected from the range sensor?

 

[Danno]

South Main Auto on YouTube does this type of wiring trouble shooting all the time. Might be worthwhile to get a feel for it and watch a few of Eric Os videos. Some good one's posted recently.

 

[D60]

South Main Auto on YouTube does this type of wiring trouble shooting all the time. Might be worthwhile to get a feel for it and watch a few of Eric Os videos. Some good one's posted recently.

In fact he recently did an EVAP sensor where he admits he got lucky by wiggling the harness and just happened to catch on his tablet screen in his peripheral vision it flicker from effectively ERROR to OK

Same concept as a PowerProbe tone....



Granted, he also does more methodical vids that are less poke 'n hope, but it's better to be lucky than good

 

[Jonas]

The fuse in question is said to control the 1. charging system, 2. rear window defogger, 3. backup lights.
Per a recommendation from a Toyota forum, I disconnected the alternator (low voltage connector) and started the car.
It ran without blowing the fuse, but then I turned on the rear window defogger, and the fuse blew a second or 2 later.
That could just be a coincidence, since the engine will sometimes run briefly before the fuse blows.
I then replaced the fuse, but it blew as soon as I turned the car on before starting (alt still disconnected, defogger off)
Does this offer anything conclusive? Maybe rule out the alternator?

 

[D60]

I'd reinspect the boot at rear hatch and see if you can find a plug under headliner. Unplug that and see if fuse still blows.

That said, I'm not sure power should be present anywhere back there for rear defrost if the switch is not on?

Corrosion related to reverse lights is another possibility, but same story -- not sure this would blow the fuse unless the NSS sends power back there for reverse?

However maybe Toyota switches the ground(s) and hot is always present for one or both of these -- not sure

 

[JTK]

Different vehicle, but I know on the Nissan versa, the transmission range sensor circuitry is shared with the tail lamps. Something as simple as a burnt or corroded lamp socket back there, or poor pin fitment can throw the range sensor off, mimicking transmission issues. The first thing you do in Versa world to troubleshoot this is verify all the tail lamps function and light to full brightness.