Hdc light on but no error code ?
Thread Starter
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Mudding
Joined: Sep 2020
Posts: 141
Likes: 2
From: Oshawa, Ontario, Canada
Hdc light on but no error code ?
2002 D2
From time to time my HDC orange light comes on but there is no error code associated with it%
Has anybody else have this issue or can you give me some insight? Thanks
From time to time my HDC orange light comes on but there is no error code associated with it%
Has anybody else have this issue or can you give me some insight? Thanks
TReK
Joined: Oct 2007
Posts: 2,768
Likes: 1,981
From: Whidbey Island, PNW
Funny you mention that -- I just solved this, I had an intermittent orange HDC warning lamp on my 2000. Check out my post from a couple days ago on here.
Was the passenger interior fusebox, had gotten wet over the years and was corroded.
I did get codes though for the "brake lamp relay" aka "HDC relay" . Apparently this non-replaceable relay that is soldered into the passenger compartment fusebox controls the brake lamps when HDC is on. Separately from the rest of the brake light switch at the brake pedal btw.
Side note: You'll need to read these codes with something that gets codes from the SLABS unit ie ABS controller. Some code readers don't get these properly I think. So for example, my OBD2 reader didn't get these codes.
Was the passenger interior fusebox, had gotten wet over the years and was corroded.
I did get codes though for the "brake lamp relay" aka "HDC relay" . Apparently this non-replaceable relay that is soldered into the passenger compartment fusebox controls the brake lamps when HDC is on. Separately from the rest of the brake light switch at the brake pedal btw.
Side note: You'll need to read these codes with something that gets codes from the SLABS unit ie ABS controller. Some code readers don't get these properly I think. So for example, my OBD2 reader didn't get these codes.
Thread Starter
|
Mudding
Joined: Sep 2020
Posts: 141
Likes: 2
From: Oshawa, Ontario, Canada
Funny you mention that -- I just solved this, I had an intermittent orange HDC warning lamp on my 2000. Check out my post from a couple days ago on here.
Was the passenger interior fusebox, had gotten wet over the years and was corroded.
I did get codes though for the "brake lamp relay" aka "HDC relay" . Apparently this non-replaceable relay that is soldered into the passenger compartment fusebox controls the brake lamps when HDC is on. Separately from the rest of the brake light switch at the brake pedal btw.
Side note: You'll need to read these codes with something that gets codes from the SLABS unit ie ABS controller. Some code readers don't get these properly I think. So for example, my OBD2 reader didn't get these codes.
Was the passenger interior fusebox, had gotten wet over the years and was corroded.
I did get codes though for the "brake lamp relay" aka "HDC relay" . Apparently this non-replaceable relay that is soldered into the passenger compartment fusebox controls the brake lamps when HDC is on. Separately from the rest of the brake light switch at the brake pedal btw.
Side note: You'll need to read these codes with something that gets codes from the SLABS unit ie ABS controller. Some code readers don't get these properly I think. So for example, my OBD2 reader didn't get these codes.
TReK
Joined: Oct 2007
Posts: 2,768
Likes: 1,981
From: Whidbey Island, PNW
In my case, yes, it was the passenger compartment fusebox under the steering wheel (left / drivers side). Full of corrosion.
I researched this ALOT and yes, it could be a poor connector or wiring issue elsewhere, but from what I read here and on the Aussie and Brit Disco boards (I went deep on this), the fusebox is normally the culprit. Could also be a wire between fuse box and BCU. But in my case it was Fusebox
You may think I'm INSANE but here is an Apple note I pasted in... it shows every single connector and wire involved, and some of my 'theory'. I literally stayed up until wee hours multiple nights on this until I figured it out -- fusebox. HDC WARNING LIGHT FAULT TRACING
According to RAVE, HDC warning lamp alone indicates the Brake Lamps Relay is open or short circuit.
Two codes I am getting
101:Brake Light Relay Drive Short to Supply
081:Brake Light Relay Short to Supply
Most car electrical opens are the result of a:
Check out https://www.aulro.com/afvb/discovery...ght-issue.html
https://www.landyzone.co.uk/land-rov...i-dumb.160328/
FUSEBOX INFO
https://expeditionportal.com/forum/t...n-a-d2.136529/
ScribD post - unrelated to what I did but this guy is ambitious
https://www.scribd.com/doc/195372926...d-Relay-Repair
Fusebox locks on a 2004 -normally apparently this is what goes wrong with the fusebox - https://www.landroversonly.com/threa...nt-work.71257/
"Just replaced a hub this morning to get rid of my 3 amigos. It worked but I still have uno amigo. My Hill descent light is on and my scanner is reading one code. "Brake Light Relay short to internal supply" the best info I can find on that is to inspect and or replace my hill descent relay. I can;t seem to locate that? Where is this really? Am I on the right track?
According to RAVE, HDC warning lamp alone indicates the Brake Lamps Relay is open or short circuit.
It doesn't effect function of any of ABS, ETC, HDC, or EBD. I would check out the brake lights.
Info in these...
PG 102 /// INFO FROM ELECTRICAL LIBRARY
PG 874 RAVE
When HDC is enabled, the SLABS ECU calculates a target speed from the throttle position element of the engine data input, and compares this with actual speed. If the actual speed is higher than the target speed, the SLABS ECU
operates the ABS modulator in the active braking mode to slow the vehicle down to the target speed. While the braking force is being applied, the SLABS ECU also energizes the brake lamp relay to put the brake lamps on. Active braking is discontinued while vehicle speed is below the target speed or if the foot brakes are applied. Applying the foot brakes during active braking may result in a pulse through the brake pedal, which is normal.
PG 871 RAVE
Slabs ECU Pinout
C0506 connector
Pin 9 - goes to brake lamp relay. INCORRECT WHERE IS THIS FROM?
Pin 12 - goes to brake lamp (HDC) relay
PG 876 RAVE
Brake lamps relay Open/Short circuit Off Off Off On (HDC)
Warning lamp fault operation
After detecting a fault, the SLABS ECU selects an appropriate default strategy which, where possible, retains some
operational capability. A shuttle valve switch fault and throttle position signal fault are classified as permanent faults. If a permanent fault is detected, the related warning lamp illumination and default strategies are automatically employed in subsequent ignition cycles, even if the fault is intermittent, until the fault has been rectified and cleared from memory. If a non permanent fault is detected, the related warning lamp illumination and default strategies will only be employed in subsequent ignition cycles if the fault is still present.
I researched this ALOT and yes, it could be a poor connector or wiring issue elsewhere, but from what I read here and on the Aussie and Brit Disco boards (I went deep on this), the fusebox is normally the culprit. Could also be a wire between fuse box and BCU. But in my case it was Fusebox
You may think I'm INSANE but here is an Apple note I pasted in... it shows every single connector and wire involved, and some of my 'theory'. I literally stayed up until wee hours multiple nights on this until I figured it out -- fusebox. HDC WARNING LIGHT FAULT TRACING
According to RAVE, HDC warning lamp alone indicates the Brake Lamps Relay is open or short circuit.
Two codes I am getting
101:Brake Light Relay Drive Short to Supply
081:Brake Light Relay Short to Supply
Most car electrical opens are the result of a:
- corroded connection,
- loose wire,
- disconnected wire,
- failed load,
- blown fuse,
- burned out bulb,
- or damaged wire (frayed, chaffed or burnt)
- Visual chk of all brake lights rear
- RR taillight assembly / internal corrosion in the bulb holder areacan back-feed and cause weird issues
- New LR taillight assembly (same)
- Brake pedal switch swap out with new style (noticed that sometimes brake lights didn’t come on when car was off and didn’t work at other times) - WHEN IT ARRIVED I compared with https://landroverforums.com/forum/di...8-95-ab-71713/
- Chk ground 0706 (RR taillight ground) - water leaking in cargo area / cargo door can foul this
- Chk ground 0707 (LR taillight ground) - same
- Fuse 25 passenger compartment 15 amp - “Brake Pedal Switch” this goes to Hill Descent Relay as well in pass compartment fusebox
- Fuse 27 pass compartment 10 amp - “Header 760”
- Fuse 28 pass compartment 10amp - “Slabs ECU”
- Chk ground here - Header-Earth-0017 (K108) - this is where HDC relay on fusebox grounds to - black wire — it’s here. Check pin #1 at this location, C0017-01 (below)
- Black-Green wire between BCU and Fusebox at BCU - CO506-12
- Black-Green wire between BCU and Fusebox at Fusebox - C0586-13
- From fusebox, check wire going to ground point 0017 - it’s a black wire C0583-1 at fusebox. This goes to above ground point C0017-01
- Check fusebox for damage / corrosion — figure out which of the little relays is HDC/brake lamps
- After checking ground wire between fusebox and ground, check the other wire - C0588-16 (green/purple) out back of fusebox
- Check C0287-2 (Green/Purple in) / C0287-5 (Green/Purple out) - which is connector at brake light switch area
- Check C0295-4 (Green/Purple In) - and then 5/6 (both green/purple outs)
- Relay Hill Descent R222 in pass fuse box -trace wires to it - but it is not replaceable or serviceable
- Header 0287 K109 -chk this wire bundle
- Chk c0484-9/c0102-9. (Green purple)
- Co688-2/co681-2 (under center console -really a last resort
- Question - HDC relay - is there one somewhere? Or is it same as “brake lamp relay” that’s built into the fuse box. If it’s fried, out of luck need new fusebox (https://www.aulro.com/afvb/discovery...ght-issue.html). I FIGURED OUT THE ANSWER - YES IT IS THE SAME.
Check out https://www.aulro.com/afvb/discovery...ght-issue.html
https://www.landyzone.co.uk/land-rov...i-dumb.160328/
FUSEBOX INFO
https://expeditionportal.com/forum/t...n-a-d2.136529/
ScribD post - unrelated to what I did but this guy is ambitious
https://www.scribd.com/doc/195372926...d-Relay-Repair
Fusebox locks on a 2004 -normally apparently this is what goes wrong with the fusebox - https://www.landroversonly.com/threa...nt-work.71257/
"Just replaced a hub this morning to get rid of my 3 amigos. It worked but I still have uno amigo. My Hill descent light is on and my scanner is reading one code. "Brake Light Relay short to internal supply" the best info I can find on that is to inspect and or replace my hill descent relay. I can;t seem to locate that? Where is this really? Am I on the right track?
According to RAVE, HDC warning lamp alone indicates the Brake Lamps Relay is open or short circuit.
It doesn't effect function of any of ABS, ETC, HDC, or EBD. I would check out the brake lights.
Info in these...
PG 102 /// INFO FROM ELECTRICAL LIBRARY
PG 874 RAVE
When HDC is enabled, the SLABS ECU calculates a target speed from the throttle position element of the engine data input, and compares this with actual speed. If the actual speed is higher than the target speed, the SLABS ECU
operates the ABS modulator in the active braking mode to slow the vehicle down to the target speed. While the braking force is being applied, the SLABS ECU also energizes the brake lamp relay to put the brake lamps on. Active braking is discontinued while vehicle speed is below the target speed or if the foot brakes are applied. Applying the foot brakes during active braking may result in a pulse through the brake pedal, which is normal.
PG 871 RAVE
Slabs ECU Pinout
C0506 connector
Pin 9 - goes to brake lamp relay. INCORRECT WHERE IS THIS FROM?
Pin 12 - goes to brake lamp (HDC) relay
PG 876 RAVE
Brake lamps relay Open/Short circuit Off Off Off On (HDC)
Warning lamp fault operation
After detecting a fault, the SLABS ECU selects an appropriate default strategy which, where possible, retains some
operational capability. A shuttle valve switch fault and throttle position signal fault are classified as permanent faults. If a permanent fault is detected, the related warning lamp illumination and default strategies are automatically employed in subsequent ignition cycles, even if the fault is intermittent, until the fault has been rectified and cleared from memory. If a non permanent fault is detected, the related warning lamp illumination and default strategies will only be employed in subsequent ignition cycles if the fault is still present.
Last edited by nashvegas; Oct 13, 2020 at 10:18 AM.
TReK
Joined: Oct 2007
Posts: 2,768
Likes: 1,981
From: Whidbey Island, PNW
PDF with images now attached
Well crap the images didn't post up properly and I spent an hour adding them. Amazing!
Im going to bed but -- if you think they'd help I've PDF'd the apple note and it's attached here complete with images
Im going to bed but -- if you think they'd help I've PDF'd the apple note and it's attached here complete with images
Thread Starter
|
Mudding
Joined: Sep 2020
Posts: 141
Likes: 2
From: Oshawa, Ontario, Canada
on cold starts my truck has the M plus S light flashing (no check engine flash). This puts my truck into limp mode and is stuck in third gear. The funny thing is if I turn off the truck and start it right back up the flashing lights and the limp mode is gone.
The official error code I get during the lights flashing is; “P0748 Pressure Control Solenoid A Electrical”
now because this only happens on cold days. And only cold starts, and disappears When the truck is turned off and restarted in my mind it leads me to believe it’s a battery issue right? But the battery reads 12.6- 12.8 Cold. And 13.6 while running.. I drove the truck to my local parts store and did a load test on the battery and it passed up to 800 cold cranking amps it did fail on 900 cold cranking amps. Those are the facts know if you were me how would you go about tackling this little situation.
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