‘01 LC idiot lights

[B1oodyBuzzard]

Hi I’ve been throwing parts at my truck and I’m getting tired of it. Most of it was needed suspension but I’m stumped with the idiot lights.

1.) C1340 Center Diff Lock that seems to trigger the VSC lights. I’ve replaced the switch with no luck. Old switch also tested good. VSC light occasionally clear themselves.

2.) P0171 and P0174 lean banks 1&2.
-I’ve replaced all 4 O2 sensors, Maf sensor, fuel filter.
-A smoke test revealed a crack in the plastic intake so I epoxy it. No leaks found after.


Thanks for the help.

 

[Snow Wagon]

Hello B1oodyBuzzard,
Check out this thread.

Thread 'P0171 and P0174 Lean condition on my new LX470 ...'

Mar 27, 2016

Got a Check Engine light this morning.

My ELM327 scanner says the fault is:
P0171 – Powertrain System too Lean (Bank 1)
P0174 – Powertrain System too Lean (Bank 2)

This is a new to me 2002 LX470 with only 25K miles.

What's the thinking about how to troubleshoot this issue?

• cwmoser
• Replies: 39
• Forum: 100-Series Cruisers

Hopefully it helps with the 2nd issue above.

Good luck.
Tom

 

[2001LC]

Good job finding an fixing vacuum leak.

I would:

1. Monitor fuel trims, while driving on HWY. See if LTFT runs rich and STFT run lean: While steady at~2200 RPM & ~65MPH on flat HWY.
2. Do a fuel pressure test, by the book (FSM).

If fuel pressure regulator not holding pressure in rails. You'll not have enough fuel pressure in to injectors.

Did fuel filter backwash, look bad? If so, that's a clue of bad fuel.

If fuel pump weak. You'll not have enough fuel volume/pressure in rails to injectors.

 

[GoziLX424]

Hi I’ve been throwing parts at my truck and I’m getting tired of it. Most of it was needed suspension but I’m stumped with the idiot lights.

1.) C1340 Center Diff Lock that seems to trigger the VSC lights. I’ve replaced the switch with no luck. Old switch also tested good. VSC light occasionally clear themselves.

2.) P0171 and P0174 lean banks 1&2.
-I’ve replaced all 4 O2 sensors, Maf sensor, fuel filter.
-A smoke test revealed a crack in the plastic intake so I epoxy it. No leaks found after.


Thanks for the help.

I have a 2006 LX470 w 215K mi. So I was getting the same codes switching back and forth with the VSC OFF light on while the mechanic was driving around and it didn't make any sense. Checked for vacuum leaks and nothing. Engine checked out fine. Cleaned out the MAF sensor and changed the air filter and cleared the codes and seemed to be fine. But when left to idle for about 10 minutes the code comes back and the VSC and engine light comes back on. Mechanic thinks it's an ECU problem not a mechanical problem. UNTIL a few days later the car wouldn't start all of a sudden. No crank just all lights on, no click. Then tried it again and then after trying twice it finally started with VGRS light on. Drove it around to reset VGRS and it went away.

So I did something that I should have done the first time I started having this issue. I checked the battery charge and lo and behold the standing charge was below 12V. So I read that a low battery tends to cause phantom codes because the LX has a lot of power hungry components. Changed the battery and so far haven't had any issues. So crossing my fingers, but the car is running smooth for now with no weird codes popping up.