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IS220d (07) - Wiring Diagram /ECU


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Having difficulty finding wiring diagram to identify why steering stalks are not fully functioning. 

When Ignition on I have no Indicators, Horn, Fogs, Most windscreen functions, and headlights.  Oddly had this last weekend, got it all back after pulling fuses and connectors, then car parked for 4 days then nothing again, have removed the stalk and see link cable to indicator stalk so now realise main control circuit is on Windscreen Stalk.

Oddly when Ignition is Off I have a horn and headlight indication - weird one,

I suspect stalk or an an ECU  - but which one?

Any advise welcome, have tried to download a supposed manual from Cardiagn.com but only can get the doc converter loaded.

Thanks in advance

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The wiper switch assembly gets power through MPX-B and ECU-IG fuses. The first is a permanent feed and the other on ignition.

You are correct, the horn and headlight controls etc all connect into the wiper switch assembly which then has bus connections to the body ECU / power control ECU / Gateway ECU etc.

You can get the official wiring diagrams and repair manual on a subscription basis from Lexus:

https://www.lexus-tech.eu

You may only need an hour.

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Thank you Colin, very prompt, and useful info.

What do you mean by an hour - to view the wiring diagrams, or to do the job?

MPX - B = is this a multiplexer and is it the item identified as Block B in theengine compartment main fuse box?  I have swopped this with another and no improvement.

Regards

Stan

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Have visited the tech website - very good, have registered but not yet subscribed as will wait for morning for a refresh of mind.

I guess you mean an hour subscription.

Curious about the MPX-B though and its location -  Also how to prove the stalk circuit.  

In your opinion what would you suspect?

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WELL DONE LEXUS and Colin

Have registered and paid 2 hr subscription for access to the support as suggested by Colin.  Cost is not inc tax hence 6Euro becomes 7.20euro.

Well worth it - caution needed to differentiate between pre2009 and post 2009, also LHD and RHD.  Able to download and print diagrams whilst researching which was brilliant.

Worth reviewing the Maintenance Manuals as diagnostics info worth reading, although confidence in using Multimeters and access to diagnostic reader required.

 

 

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Update on IS220d Headlight, Indicator, Horn and Wiper issues. 

Discovered with help, that when ignition NOT ON - Headlights, Fogs and SideLights all function.  When Ignition turned on to accessory or ON then all functions are not working (except fast wiper position). 

Oddity 1 - Also discovered that when Indicator positioned either RH or LH and then Ignition depressed to Acessories or ON they work for approx 6 repetitions then stop - if try to change RH to LH or vice-versa original indicator chosen stays on for 6 repeats.

Have now changed Wiper Stalk with ECU to prove the stalk works fine in another car.  Oddly/stupidly forgot to refit the "B Block" in the  engine bay fuse compartment and stalk still functioned wipers and indicators.

Have removed and refitted all relays in the engine fuse boxes - just in case a terminal was dirty - still no joy.

Oddity 2 - In amongst all this the only other malfunction is the CD/Audio lower panel function switches - nothing works, radio function works from buttons on dash or steering wheel, just cannot switch it off or change options with the lower panel.

CONCLUSION SO FAR
My belief now is that one of the Communication ECU's has thrown a wobbly - which one though?

DIFFICULTY ONE - The system information gleaned from Lexus does not reveal/identify precisely which does what (still learning about this).

A reference is made to ECU LH, in the Turn Signal Diagnosis, which I assume is in the footwell fuse box on the passenger side, but at the moment I can find no reference to the fusebox (i assume with an ECU also) on the RH (drivers) footwell - and assume it also plays a part within the communications loom.

DIFFICULTY TWO - Is there a possible electronic gremlin that links both the Audio control malfunction and the main stalk problems I have?

HAS ANYONE HAD A SIMILAR ISSUE and can offer some ideas?

(away to work for 3 days)

Where is Gateway ECU?

 

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HELP NEEDED - Where is the Multiplexer located?  I think it is on the LHS (passenger side), adjacent to the fuse box - but I have a doubt if this is correct.

Cannot see it identified on the drawings so am perplexed - also uncertain if I can swop it with another from a different car.  Has anyone done this?

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On 5/19/2018 at 12:23 PM, STANSKI said:

HELP NEEDED - Where is the Multiplexer located?  I think it is on the LHS (passenger side), adjacent to the fuse box - but I have a doubt if this is correct.

Cannot see it identified on the drawings so am perplexed - also uncertain if I can swop it with another from a different car.  Has anyone done this?

More Knowledge - Multiplexer B is on LHS.  MUltiplexer A with Microprocessor is on RHS (right of Fuse Box)

NO SECURITY or START PROBLEM

Reviewed what I had done and for piece of mind started again thus disconnected Battery, Took LHS fuse box out again, disconnected mutltiplexer also, reviewed all fuses and found I had misplaced a fuse in a gapped one (Security Start/Stop - Fuse 8 ) - Phew!

At same time disconnected and reconnected all available LHS connectors located on body panel. Reconnected Battery - voila - ALL systems are now working (except passenger door mirror) - but main functions are OK.   I have to assume I have corrected a dodgy pin connection, or reset a setting by default within the CAN system, or struck lucky. 

Still would like to know if I could have swopped Multiplexer with another - I am confident it would be OK, but ?

 

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  • 2 weeks later...

Can't answer the question about the Multiplexer but just wanted to comment that when dealing with 'odd' electrical problems, the gremlin often turns out to be a damaged or poor quality earthing connections (usually corrosion related). Worth bearing in mind.

Also, thanks for updating the thread as this will probably be useful info to another owner one day.

 

 

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