I recently purchased an 05 LR3 with locking rear diff that has been a bit of a project due to prior sunroof and hood cowl-related water ingress and a lazy prior owner. I have since eliminated the water ingress and am drying/cleaning the carpets while cleaning up any dirty electrical connections I can find.

When I purchased the car it had the yellow brake light on which the seller said was from one of the brake wear sensors needing to be replaced. On the highway, as I was driving it home, the check engine light came on for p0171 and p0174. I then decided to replace the MAF sensor, PCV valve, and clean the Throttle body. I also detailed the engine bay using diluted simple green that I carefully sprayed on my rags and around certain engine areas. I was careful not to soak anything and thought this would work out.

When I went to start the engine up, about every light came on including HDC fault, Transmission fault limited gears available, special programs off, Parking Brake light illuminated, Brake light still illuminated, and check engine light. Also the car keeps lowering itself to lowest suspension setting.

I recently picked up a GAP tool which shows the following codes:

Body Control

• B1B02-28 (2F) Low frequency coil - General signal failure - signal bias level is out of range/zero adjustment failure
  ( on 20-06-2023 17:43:02 at 189340 km )
• B1C57-14 (6C) Passive start ignition relay coil circuit - General electrical failure - circuit short to ground or open
  ( on 20-06-2023 17:42:42 at 189340 km )
• B1D12-15 (2E) Volumetric alarm power circuit - General electrical failure - circuit short to battery or open
  ( on 20-06-2023 17:48:29 at 189340 km )

Engine Petrol

• P0102-00 (AA) Mass or volume air flow circuit low input

Parking Brake

• U0100-87 (EB) Lost communication with engine control module/powertrain control module 'A' - Bus signal/message failure - missing a message
  ( on 20-06-2023 17:43:49 at 189348 km )

Transmission

• U2023-86 (AF) Control module network signal calibration data - Bus signal/message failure - signal is invalid
  ( on 20-06-2023 17:36:57 at 189348 km )

Vehicle Dynamic

• U0401-68 (0B) Invalid data received from engine control module/powertrain control module - Algorithm based failure - event information
  ( on 20-06-2023 17:39:26 at 189348 km )

To give some background the most recent service the previous owner had done was for a new battery, new alternator, and new TCCM (about a month ago). I removed the battery and TCCM and the TCCM still looks new and in good shape so I don't think that is the issue. I briefly looked at the connections behind the battery area and don't see any corrosion or anything.

Any ideas on what I might have done to cause these lights to all go off? I ordered a new brake sensor switch to swap that out as I read it can cause problems, but I'm leaning towards this being something I did in the engine bay since all those lights came on after I replaced the MAF, PCV valve, and cleaned engine bay/throttle body.

 

Running voltage?

 

Hanging around 14.06-14.10 mostly when checking at the battery posts. It was measuring about 12.46-12.48 with the car off.

 

...maybe try clearing all faults and then see which ones return???

 

I cleared them several times, these are the ones that return. I'm thinking there may be a wire I bumped or got wet or something. I found some small evidence of a mouse nest near the passenger side intake manifold, I'm wondering if they chewed on something that I then knocked loose.

 

Oh well.....a mouse next is a plot twist!

You will definitely want to go through all the wiring....they love the soy-based insulation.

 

Any new cracks in the PCV hose from the install?

You try reinstalling your old MAF to rule out the new one being a dud?

Also you may have gotten water on the back of the fuse box (its on the passenger side firewall (fuses are behind the glovebox but the rear connections are open to water ingress under the cowl)

 

You're a genius! I don't know why I didn't think to put the old MAF back on...when I did that everything went back as it was before it all went haywire. Thank you!!

Now I have one new issue, the rear tailgate won't open at all. Seems like power is not getting to it in any way...any ideas? Everything I can find on the rear tailgate seems to be related to the mechanical parts, but mine doesn't seem to be getting any power now.

 

I'd check the fuse first and go from there.

The new MAF you got, was it made be Denso? If not, definitely try to stick to those, these trucks can get finnicky with lower quality electric parts.

 

The new one was a Toyota part. I had read on several posts that Toyota part number 22204-22010 would work so I went with that.

I just got done searching through my manual and can’t seem to locate the fuse for the rear tailgate, do you know which one it is? There is also a chance I need to Re seat one of the rear connectors on the CJB from when I did the front passenger sunroof drain. Really hoping this is not the case though as my hands are beat up from getting that done the first time around.