2003 Amazon ahc no power to relay (2 Viewers)

[Trb]

Got 100 series with ahc blinking
Had fluid leek all oil came out and alternator replacement
Been jump started a few times possible wrongly
Fixed leek filled with new Toyota oil
Now will not raise
No power to relay but power to 40amp fuse
Help please

 

[ClassyJalopy]

If the relay is not getting any power, and fuse is intact, I would connect the Techstream and see if the AHC controller is even active/alive?

 

[Trb]

I get
C1711
C1712
C1718
From Toyota intel tester 11
Providing I am using correctly

 

[Trb]

Got 100 series with ahc blinking
Had fluid leek all oil came out and alternator replacement
Been jump started a few times possible wrongly
Fixed leek filled with new Toyota oil
Now will not raise
No power to relay but power to 40amp fuse
Help please

 

[ClassyJalopy]

Looks like it can't read the pressure sensor or the front height censors. Unless you have recently disconnected a bunch of plugs on AHC, I would worry if the AHC controller got toasted due to reverse polarity on jump starter.

This thread has a lot of relevant AHC information. @LndXrsr and @suprarx7nut are also very knowledgeable for AHC related issues.

 

[suprarx7nut]

You've got *7* DTC, not just 3. The screen shows 3 at a time, but you appear to have 7. I suspect some sort of electrical fault. Try clearing them and then checking. If 7 still exist, post all of them up. Maybe something will pop out at us.

 

[ramangain]

Wait, you KNOW you've reversed polarity trying to jump the rig, possibly more than once?

Sell the rig and get a pronged electric car. Hard to fu(k that up since they typically only plug in one way.

 

[Trb]

If the relay is not getting any power, and fuse is intact, I would connect the Techstream and see if the AHC controller is even active/alive

You've got *7* DTC, not just 3. The screen shows 3 at a time, but you appear to have 7. I suspect some sort of electrical fault. Try clearing them and then checking. If 7 still exist, post all of them up. Maybe something will pop out at us.

 

[Trb]

Yes I can see that there is 7 now
I pretty sure I tried to clear but wouldn’t let me
Will plug in again see what else is there are should they be on that screen shot i sent
I’m just new to using the diagnostic
And will look at the other threads you mentioned
Thanks for help so far on my nightmare

 

[Trb]

Wait, you KNOW you've reversed polarity trying to jump the rig, possibly more than once?

Sell the rig and get a pronged electric car. Hard to fu(k that up since they typically only plug in one way.

I’m not 100% sure we did it was just a thought as to it causing something to blow
Thanks for input cheers

 

[IndroCruise]

Got 100 series with ahc blinking
Had fluid leek all oil came out and alternator replacement
Been jump started a few times possible wrongly
Fixed leek filled with new Toyota oil
Now will not raise
No power to relay but power to 40amp fuse
Help please

Late Edit: Pic of location of AHC IG fuse added.

One of my own basic mistakes is to forget to close all doors and the rear hatch on the vehicle when doing AHC tests. If any of these are open, the AHC system is prevented from operating for safety reasons. The system is interlocked with the door switches. It is OK if the engine hood is open – because there is no interlock switch here.

As already mentioned by @suprarx7nut , it is important to start the investigation by clearing the Diagnostic Trouble Codes (DTC’s) which may have accumulated in the Electronic Control System (ECU) memory. If some DTC’s return after clearing, then that indicates real ongoing faults which will need to be resolved.

Suggest post these ongoing faults on this IH8MUD thread so that Members can offer further comments:

There are several ways to clear DTC’s:

Use the clearing function on the handheld device or Techstream.

If unsuccessful, use the manual method described at Post #6 at this link to clear DTC’s:
AHC wont raise after battery out - https://forum.ih8mud.com/threads/ahc-wont-raise-after-battery-out.1250534/#post-13814584

Alternatively, try re-booting the system. To do this, disconnect the battery or batteries and allow the system to power down, then re-connect the battery or batteries and re-start.

A fluid leak was mentioned. If the AHC Pump ran dry even if only momentarily, it will have stopped momentarily, at least until it was re-primed with AHC Fluid. In this case, these Diagnostic Trouble Codes (DTC) may be recorded by the ECU and will need to be cleared:
C1751 – AHC Pump & Motor
C1762 – Pressure Malfunction

It is also possible that an electrical disruption such as ‘jump starting’ may cause the AHC Main Relay to stop and show this DTC:
C1743 – AHC Main Relay Function
Some hints on overcoming this problem are found at Post #1 by @PADDO at this link:
AHC DTC C1743 - main relay - https://forum.ih8mud.com/threads/ahc-dtc-c1743-main-relay.914138/
(Refers to AHC IG fuse which is found here -- behind cover in Left Hand footwell):

Hopefully, you will not see the DTC which indicates malfunction of the ECU. If it appears, it indicates that the ECU has stopped due to internal memory errors. This requires replacement of the ECU. The AHC system will not work correctly and may not work at all with a faulty ECU.
C1761 – Malfunction of ECU

If you wish to explore the "Diagnostic Section" and "On-vehicle Section" of the Factory Service Manual (FSM) for Active Height Control (AHC) and the Toyota Electronic Modulated Suspension (TEMS), then the following are useful references:

AHC Diagnostics:
https://lc100e.github.io/manual/
At this link, use the Index on the left hand side of the opening page and follow these tabs:
Repair Manual > DIAGNOSTICS > ACTIVE HEIGHT CONTROL & SKYHOOK TEMS

AHC On-Vehicle Inspection including correct AHC pressure ranges:
https://lc100e.github.io/manual/
At this link, use the Index on the left hand side of the opening page and follow these tabs:
Repair Manual > SUSPENSION AND AXLE > ACTIVE HEIGHT CONTROL SYSTEM (Independent Front Suspension) > ON-VEHICLE INSPECTION

Hope this gives you a few thought-starters!

 

[Trb]

Thanks so much for your help
Will go through all possible problems you mentioned
Thanks again

 

[Trb]

Hi connected diagnostics and got same faults but as you said showing 7
But can’t find them but got some photos of what I found also every time I try active test diagnostics freezes and have to start again

 

[Trb]

Hi looks like I got Couple off phots on by mistake lol

 

[Trb]

Late Edit: Pic of location of AHC IG fuse added.

One of my own basic mistakes is to forget to close all doors and the rear hatch on the vehicle when doing AHC tests. If any of these are open, the AHC system is prevented from operating for safety reasons. The system is interlocked with the door switches. It is OK if the engine hood is open – because there is no interlock switch here.

As already mentioned by @suprarx7nut , it is important to start the investigation by clearing the Diagnostic Trouble Codes (DTC’s) which may have accumulated in the Electronic Control System (ECU) memory. If some DTC’s return after clearing, then that indicates real ongoing faults which will need to be resolved.

Suggest post these ongoing faults on this IH8MUD thread so that Members can offer further comments:

There are several ways to clear DTC’s:

Use the clearing function on the handheld device or Techstream.

If unsuccessful, use the manual method described at Post #6 at this link to clear DTC’s:
AHC wont raise after battery out - https://forum.ih8mud.com/threads/ahc-wont-raise-after-battery-out.1250534/#post-13814584

Alternatively, try re-booting the system. To do this, disconnect the battery or batteries and allow the system to power down, then re-connect the battery or batteries and re-start.

A fluid leak was mentioned. If the AHC Pump ran dry even if only momentarily, it will have stopped momentarily, at least until it was re-primed with AHC Fluid. In this case, these Diagnostic Trouble Codes (DTC) may be recorded by the ECU and will need to be cleared:
C1751 – AHC Pump & Motor
C1762 – Pressure Malfunction

It is also possible that an electrical disruption such as ‘jump starting’ may cause the AHC Main Relay to stop and show this DTC:
C1743 – AHC Main Relay Function
Some hints on overcoming this problem are found at Post #1 by @PADDO at this link:
AHC DTC C1743 - main relay - https://forum.ih8mud.com/threads/ahc-dtc-c1743-main-relay.914138/
(Refers to AHC IG fuse which is found here -- behind cover in Left Hand footwell):
View attachment 2673836

Hopefully, you will not see the DTC which indicates malfunction of the ECU. If it appears, it indicates that the ECU has stopped due to internal memory errors. This requires replacement of the ECU. The AHC system will not work correctly and may not work at all with a faulty ECU.
C1761 – Malfunction of ECU

If you wish to explore the "Diagnostic Section" and "On-vehicle Section" of the Factory Service Manual (FSM) for Active Height Control (AHC) and the Toyota Electronic Modulated Suspension (TEMS), then the following are useful references:

AHC Diagnostics:
https://lc100e.github.io/manual/
At this link, use the Index on the left hand side of the opening page and follow these tabs:
Repair Manual > DIAGNOSTICS > ACTIVE HEIGHT CONTROL & SKYHOOK TEMS

AHC On-Vehicle Inspection including correct AHC pressure ranges:
https://lc100e.github.io/manual/
At this link, use the Index on the left hand side of the opening page and follow these tabs:
Repair Manual > SUSPENSION AND AXLE > ACTIVE HEIGHT CONTROL SYSTEM (Independent Front Suspension) > ON-VEHICLE INSPECTION

Hope this gives you a few thought-starters!

 

[Trb]

Hi any thought on diagnostics phot I sent
End of my tether with this situation

 

[IndroCruise]

Hi any thought on diagnostics phot I sent
End of my tether with this situation

@Trb – to move forward, some response is essential to the feedback previously provided to you.

Can you please confirm that you are operating the handheld tester with all vehicle doors and rear hatch closed?

Diagnostic Trouble Code (DTC) C1783 Door Courtesy Switch is shown in your first picture in your Post #13 above. This suggests that a door is open. If a door or rear hatch is open, the AHC system will not work.

Can you please confirm that you have cleared DTC’s as recommended in Post #8 in this thread AND used the manual methods for clearing DTC’s (without using the handheld tester) as described in the reference at Post#11 in this thread?

Can you please list exactly what DTC’s returned AFTER the previous DTC’s were cleared.

Your vehicle cannot be seen from one side of the world to the other, so your descriptions are very important. Can you please describe the symptoms -- what happens when the vehicle is started? Does the AHC Pump work? What lights are showing on the dashboard? What are the hub-to-fender physical measurements at each wheel, measured by a tape-measure? Can the vehicle be driven? What is the ride quality?

To test the AHC system, carry out the “HEIGHT CONTROL OPERATION TEST” which is also called the “ACTIVE TEST” – do this manually (not with the handheld tester) as explained at Page 6 of the attachment. [Do not worry that this is an LX470 document – the Active Height Control (AHC) system and Toyota Electronic Modulated Suspension (TEMS) system are the same as in your vehicle].

Where the attached document mentions a Special Service Tool (SST 09843-18020) it means use a simple connector. Just use a bent paper clip or something similar to connect terminals Ts and E1 of DLC1. These circuits are low voltage – about 4.5 volts – so don’t be too alarmed about them. Follow the written instructions carefully. DLC1 is the plug in the engine bay – usually on the right hand side above the wheel arch in RHD vehicles with the word “DIAGNOSTIC” on the cover.

By the way, the “prohibited operation” shown when attempting the "Active Test" on your hand-held tester MAY be caused by the AHC Electronic Control Unit (ECU) putting the system in "fail safe mode" as a result of the widely different Height Sensor readings also seen on your hand-held tester. So one piece of information we need to know is whether or not the “Active Test” can be performed manually as described above and in the attachment, without using the hand-held tester.

After following the above requests, please provide your feedback so that IH8MUD Members can try to provide further help.

At the moment there are many possibilities and the above information is requested to try to help you to narrow down the diagnosis.

 

[Trb]

@Trb – to move forward, some response is essential to the feedback previously provided to you.

Can you please confirm that you are operating the handheld tester with all vehicle doors and rear hatch closed?

Diagnostic Trouble Code (DTC) C1783 Door Courtesy Switch is shown in your first picture in your Post #13 above. This suggests that a door is open. If a door or rear hatch is open, the AHC system will not work.

Can you please confirm that you have cleared DTC’s as recommended in Post #8 in this thread AND used the manual methods for clearing DTC’s (without using the handheld tester) as described in the reference at Post#11 in this thread?

Can you please list exactly what DTC’s returned AFTER the previous DTC’s were cleared.

Your vehicle cannot be seen from one side of the world to the other, so your descriptions are very important. Can you please describe the symptoms -- what happens when the vehicle is started? Does the AHC Pump work? What lights are showing on the dashboard? What are the hub-to-fender physical measurements at each wheel, measured by a tape-measure? Can the vehicle be driven? What is the ride quality?

To test the AHC system, carry out the “HEIGHT CONTROL OPERATION TEST” which is also called the “ACTIVE TEST” – do this manually (not with the handheld tester) as explained at Page 6 of the attachment. [Do not worry that this is an LX470 document – the Active Height Control (AHC) system and Toyota Electronic Modulated Suspension (TEMS) system are the same as in your vehicle].

Where the attached document mentions a Special Service Tool (SST 09843-18020) it means use a simple connector. Just use a bent paper clip or something similar to connect terminals Ts and E1 of DLC1. These circuits are low voltage – about 4.5 volts – so don’t be too alarmed about them. Follow the written instructions carefully. DLC1 is the plug in the engine bay – usually on the right hand side above the wheel arch in RHD vehicles with the word “DIAGNOSTIC” on the cover.

By the way, the “prohibited operation” shown when attempting the "Active Test" on your hand-held tester MAY be caused by the AHC Electronic Control Unit (ECU) putting the system in "fail safe mode" as a result of the widely different Height Sensor readings also seen on your hand-held tester. So one piece of information we need to know is whether or not the “Active Test” can be performed manually as described above and in the attachment, without using the hand-held tester.

After following the above requests, please provide your feedback so that IH8MUD Members can try to provide further help.

At the moment there are many possibilities and the above information is requested to try to help you to narrow down the diagnosis.

Thank you will try go through each section you mention thanks terry

 

[Trb]

hi there just missing dtcs

Thank you will try go through each section you mention thanks terry

 

[Trb]

hi there just found some missing docs also must of had door open when attempting active test as fault not there the faults that are there won’t clear all fusses now checked all good will continue to go through other checks thanks terry