Rx400h Won’t start, no ready light, dash gear display blank

[Chris Rx400h]

Hi all

I've got a 2006 RX400H that will not show the ready light & therefor will not start. 

The 12 v Battery has been tested & is fine.

The gear display in the right hand side of the dash doesn’t show anything. A local garage has checked the fault memory, no faults, the engine control unit is recognising the car is in park. If I move to reverse & try & start the dash states shift to P to start, also indicating the car knows it’s in P despite the dash display.

Also if I try to move to gearshift it’s really stiff & will barely go past N, but is this because the car isn’t running?

Any help or experience if this problem greatly appreciated.

[C Mclean]

Ignition switch ?

[Delphius1]

Is the gearshift movement any easier when pressing the shift lock button?

[Chris Rx400h]

1 hour ago, C Mclean said:

Ignition switch ?

The ignition seem to power up fine, there’s also a relay clicking in when you turn the key to the “start” position, so it doesn’t seem like a ignition switch fault.

Are they prone to fail on RX models?

 

[Chris Rx400h]

1 hour ago, Delphius1 said:

Is the gearshift movement any easier when pressing the shift lock button?

I thought the shift lock button was just there to get the car out of park? Which it does anyway, but no pressing the shift lock doesn’t improve anything.

 

thanks

 

[foxy-stoat]

You shouldnt be able to move the gear stick out of park without the keys being in ignition on and foot brake on - push the button and it overrides all of that.

You sure you have at least 11 volts on both batteries ? 

[Chris Rx400h]

Yes I’m aware it should come out if park with ignition on etc.

I defiantly have over 12 volts at the Battery situated behind the right hand headlight, you say both batteries, I didn’t know it had 2, where is the other one?

Many Thanks

[Verbout]

13 minutes ago, Chris Rx400h said:

Yes I’m aware it should come out if park with ignition on etc.

I defiantly have over 12 volts at the battery situated behind the right hand headlight, you say both batteries, I didn’t know it had 2, where is the other one?

Many Thanks

😂

Comedy gold. 

[Chris Rx400h]

Go on, simple question do these have 2 x 12 volt batteries?

[acer54]

8 minutes ago, Chris Rx400h said:

Go on, simple question do these have 2 x 12 volt batteries?

I think foxy-stoat is referring to the Hybrid Battery and the normal Battery showing good voltage.........

[Chris Rx400h]

Foxy said are you sure you have more than 11 volts on both batteries, to me this implied there are 2 x 12 volt batteries. As the hybrid Battery runs at hundreds of volts not 12.

[foxy-stoat]

That came out wrong, apologises.  Ment 11+ volts on front Battery and good charge on the HV Battery.

If your not getting "ready" on the dash then you either dont have enough volts to start the system (12v battery) or maybe one or more of the ecu fues has gone.  Have you tied removing earth for a few minutes and re-connecting - to reboot the system.

[Chris Rx400h]

Yes tried disconnecting the 12v Battery.

The hybrid Battery is showing approx 70% charged 

 

thanks 

[flookyk]

6 hours ago, Chris Rx400h said:

Hi all

I've got a 2006 RX400H that will not show the ready light & therefor will not start. 

The 12 v battery has been tested & is fine.

The gear display in the right hand side of the dash doesn’t show anything. A local garage has checked the fault memory, no faults, the engine control unit is recognising the car is in park. If I move to reverse & try & start the dash states shift to P to start, also indicating the car knows it’s in P despite the dash display.

Also if I try to move to gearshift it’s really stiff & will barely go past N, but is this because the car isn’t running?

Any help or experience if this problem greatly appreciated.

Have you had a look at the gear linkages to see if they need adjusting or something happened to stop it going into P properly?

If it need to be in P for the system to set itself to ready then maybe something is stopping it going into P properly or the sensors think it is not in P so wont set itself up.

I had an old Range Rover P38 auto a few years ago that needed a new linkage cable and adjusting as it would not go into P properly ... started off with the gearshift getting stiff from N to P.

[PCM]

7 hours ago, Chris Rx400h said:

Hi all

I've got a 2006 RX400H that will not show the ready light & therefor will not start. 

The 12 v battery has been tested & is fine.

The gear display in the right hand side of the dash doesn’t show anything. A local garage has checked the fault memory, no faults, the engine control unit is recognising the car is in park. If I move to reverse & try & start the dash states shift to P to start, also indicating the car knows it’s in P despite the dash display.

Also if I try to move to gearshift it’s really stiff & will barely go past N, but is this because the car isn’t running?

Any help or experience if this problem greatly appreciated.

Worth giving your nearest Lexus garage a call?

[Delphius1]

Looking at it logically, if the 12v Battery is showing over 12v, the car knows it is in park when it's in park and not in park when it's in any other gear, if the shift display and shift action were working and both the gearbox shift and display in the dash are now not working properly, then the two are associated.

Possibly the gearbox control module is faulty,  or if you are lucky it's a blown fuse. But it really needs looking at by someone with a bit more knowledge of the car to be able to diagnose the problem. Maybe it's not showing codes to a basic reader, but something like Techscan will be able to delve a bit deeper and get to the problem.

 

[Sumtingwong]

Hi my Lexus RX400H 2006 has same issue. Changed 12v Battery for a new Bosch one. Worked better for a few weeks. Today it's come back again with the the dreaded error start when shifting to P.

It's intermittent which is frustrating.

Mechanic tested batter and said it's fine.

I'm afraid to turn on any accessories like heating, dash cam radio etc.

Changed Battery in keyfob also. 

 

Is there a way to tell if power is draining somehow when just parked for a while on driveway?

Thanks

 

[unclepoo]

It might be worth checking you have a good earth from the Battery negative to the vehicle body. Try putting a black jump lead from the Battery negative to a good clean earthing point. then see if there is any difference in starting the car.

[Sumtingwong]

Hi, thanks for taking time to respond. That is a good idea and I will try it if it happens again. I tested the Battery with a multimeter (first time I ever used one) and the results were 14v when in ready mode. When it failed to go in to ready mode it went as low as 12.4 and didn't go any lower.  As it didn't go any lower I didn't suspect a parasitic power loss.

Called several lexus specialists for advice all of them offering their condolences and diagnostics at £200 per hour. LOL then CRY. 

But one specialist did suggest the key at fault. I forgot I had a spare key, it's not an original. Tried that and it worked. To my surprise.

So I have two keys:

A - key provided with purchase of car

B - key copied from key A  using aftermarket tech (faulty)

I proceeded to test:

x30 ignition starts with key A, not one no ready light occurrence. Car always started. Success.

x30 ignition starts with key B, about 30% no ready light occurrences. Suspect faulty.

The clue lay in the flashing security light. Every time key B failed to start car. I noticed the light didn't stop flashing like it did with the working key. So I suspect a dodgy transponder in that key. 

Hope this helps someone if they have similar issue. 

 

[unclepoo]

great work fella....well done.

[Silversalmon]

A very interesting outcome, I would never have suspected a key as being the culprit. Must store that solution in my memory bank! 

[welland]

On 7/26/2018 at 7:20 AM, Chris Rx400h said:

Hi all

I've got a 2006 RX400H that will not show the ready light & therefor will not start. 

The 12 v battery has been tested & is fine.

The gear display in the right hand side of the dash doesn’t show anything. A local garage has checked the fault memory, no faults, the engine control unit is recognising the car is in park. If I move to reverse & try & start the dash states shift to P to start, also indicating the car knows it’s in P despite the dash display.

Also if I try to move to gearshift it’s really stiff & will barely go past N, but is this because the car isn’t running?

Any help or experience if this problem greatly appreciated.

Chris, did you ever get this sorted?