I had this same issue. It ended up being the park neutral switch.
2010 GX460 blinking 4LO, Check Engine and Slip lights (1 Viewer)
- Thread starter TootYa
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MrTorgue
Grizzly Clint
That's interesting. Did it throw a code?
Just had my trio of these lights come on but I suspect it's related to the SAIP filter install I did because the MAP sensor works just fine and I have zero symptoms of any issue.
From the inspection report:
Finding:
FOUND CODE P0705 TRANSMISSION RANGE SENSOR CIRCUIT (PRNDL INPUT). NEED ADDITIONAL LABOR TO REMOVE SHIFTER CABLE AND TO START TESTING ELECTRICAL SYSTEM FOR PARK NEUTRAL/SHIFT SELECTOR. VEHICLE IS VERY RUSTY UNDERNEATH. MAY HAVE TO REPLACE OTHER PARTS THAT BREAK.
MrTorgue
Grizzly Clint
Gotcha, thanks. Mine was a different code.
- Thread starter
- #45
I also originally had zero symptoms. What code is yours throwing?
MrTorgue
Grizzly Clint
P0107. Manifold absoluete pressure blah blah blah. No tough idle, no acceleration issues etc. it just so happened to of happened right after I did the SAIP breather filter mod. I wish I hadn't of thrown my foam away so I can revert it back to see if the code goes away.
- Thread starter
- #47
Yeah crazy coincidence if not related. You double checked all of the items that you disconnected, that you reconnected them properly and didnt leave something loose or forget one?
MrTorgue
Grizzly Clint
All I did was take off the cover and end cap, take out the foam, install the breather then put it all back on. Didn't unplug anything. I cleared the code but it came back.
- Thread starter
- #49
Seems to me either your MAP sensor is faulty or the wiring to the MAP sensor is faulty.
If it were me, I disconnect the sensor connector which seems super easy to get to and check the voltages per the FSM:
View attachment 3336693
E2 is ground, so with the engine on, I would check voltage across ...
pin 1 and 2 for 4.5 to 5.5V
pin 3 and 2 for 4 to 5V
MrTorgue
Grizzly Clint
Thanks!
I'll do that after I move. I ordered a replacement sensor that'll be here before we move. Since it drives ok and the fuel economy isn't impacted we'll roll with the ~1,950 mi drive to our new destination.
- Thread starter
- #51
Awwww, my lights came back on today.
P0304 again, so the problem didn't follow the coil I switched with #2.
P0304 again, so the problem didn't follow the coil I switched with #2.
- Thread starter
- #52
Gonna see if I can tell if the fuel injector sounds comparable to #2. Might be time to turn this over to a pro.
r2m
Richard
Have you tried swapping injectors and see if the problem follows wherever you put the one you suspect being bad?
That's kind of Trouble Shooting 101. If that injector is failing in any of the other cylinders, then problem solved.
- Thread starter
- #54
No, it looks really complicated to get to the fuel injectors in this bad boy. I'm a bit concerned with tearing it that far apart myself. I will say when I pulled the spark plug the engine looked pretty dirty down in the port, I am thinking about starting with running some fuel injector cleaner before I dig in too deep. Is getting to the fuel injectors on a GX460 as tricky as it looks at first glance?
Its the powertrain range control senor or I've seen it called neutral start switch assembly, there is a plastic part on the outside that cracks and fails over time. Mine went out a few months ago. Sits on the passenger side of the outside of the transmission, I didn't want to bother with it so I had a local shop install it.
Amazon product ASIN B00KTJDKMM8454060050
Amazon product ASIN B00KTJDKMM8454060050
- Thread starter
- #56
Okay I will keep this in mind in case I continue to have issues.
- Thread starter
- #57
So the fuel injectors seem complicated to get to, and I didn't want to dive that far in if I don't have to. When I pulled the spark plug, it was fouled, and visually looking inside the spark plug socket with a strong light I could see carbon (had the color of a cast iron pan).
Since the truck is at 176k and I could see carbon, I do speculate that the injector is dirty, so what I did was fill the gas tank to exactly half a tank and then dumped the most concentrated fuel injector cleaner I could find in it. I chose STP concentrated fuel injector cleaner. Then I reset the code, and then drove around in 2nd and 3rd gear, trying to keep the engine between 3000 and 3500 rpm for as much as the drive as possible. I was just trying to get temps up a bit and work the cleaner in there aggressively. I drove enough to burn about 1/4 tank of gas doing this.
I have put almost 100 miles on it since doing this and so far the lights have not come back on and no code has fired. The last time it tripped about 30 miles after a reset. So far so good.
If the lights don't come back on, I am going to repeat the fuel injector cleaner cycle a second time with a full tank of gas, but I won't run the rpms up the next time.
Since the truck is at 176k and I could see carbon, I do speculate that the injector is dirty, so what I did was fill the gas tank to exactly half a tank and then dumped the most concentrated fuel injector cleaner I could find in it. I chose STP concentrated fuel injector cleaner. Then I reset the code, and then drove around in 2nd and 3rd gear, trying to keep the engine between 3000 and 3500 rpm for as much as the drive as possible. I was just trying to get temps up a bit and work the cleaner in there aggressively. I drove enough to burn about 1/4 tank of gas doing this.
I have put almost 100 miles on it since doing this and so far the lights have not come back on and no code has fired. The last time it tripped about 30 miles after a reset. So far so good.
If the lights don't come back on, I am going to repeat the fuel injector cleaner cycle a second time with a full tank of gas, but I won't run the rpms up the next time.
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- Thread starter
- #59
Interesting. I literally just changed it right _before_ adding the fuel system cleaner. I had my 5,000 mile service, brought it home, drove it about 30 miles until the lights came on, added enough gas to get it to half a tank, then added the fuel injector cleaner. Still think I think I should swap the oil based on a brand new oil service?
r2m
Richard
Just a heads up, when I go to the link of that part in Amazon, it shows that it DOES NOT fit my vehicle.
Double check compatibility before you purchase.
