AHC L to N but not H - 01 LX470 (1 Viewer)

[donj51]

I just noticed that after a drive, my 01 LX470 AHC goes to L and N (both ways) but not high, H blinks for a couple seconds though. This has happened twice now.

After I turn off the ignition, H is not an issue. Fluid level is fine.

Of course I don’t have my laptop to look at Techstream

Any ideas?

 

[GTV]

Pressures in spec?

 

[donj51]

They were when I cross leveled and adjusted the torsion bars, but I will check.

What pressure would allow L to N but not N to H?

 

[uHu]

What pressure would allow L to N but not N to H?

I pressure which is a bit too high, front or rear.

 

[GTV]

As height increases hydraulic pressures raise accordingly, that’s why it rides firmer in H than it does in N.

Read your pressures. If they are still in spec then I would look at the height sensors.

 

[donj51]

As height increases hydraulic pressures raise accordingly, that’s why it rides firmer in H than it does in N.

Read your pressures. If they are still in spec then I would look at the height sensors.

Why would shutting off and restarting the LX change the pressure or height sensor readings so that it would then go from N to H?

 

[IndroCruise]

Why would shutting off and restarting the LX change the pressure or height sensor readings so that it would then go from N to H?

Short answer -- don’t know!

Some guesses ….

1. Assuming that there are no obvious causes like being close to maximum weight or close to maximum AHC pressures and movement to HI is just too much pressure, or, AHC Pump is partially blocked internally and not doing its thing properly,
2. Maybe check raise times LO > N and N > HI?
3. Intermittency often means a bad electrical path somewhere. Scenario: On start-up, the vehicle is stationary. The ECU reboots. All is good. Then the vehicle moves and something somewhere is ‘jostled’ a bit. Loose or problem connector somewhere? Weak spot on the carbon path inside a Height Control Sensor? Problem wire somewhere which completes a circuit when stationary but something moves and the closed circuit then opens?
4. Intermittent issues at door/hatch switches, or brake light switch, or centre console switch?
5. Erratic solenoids for Levelling Valves in the Control Valve Assembly or Height Control Accumulator solenoid not opening properly after start-up -- maybe worth testing solenoid circuits?

Multimeter, Techstream and FSM would be handy -- when they become available ….