Center diff/oil light electrical problem (1 Viewer)

[Hawgleg]

I’ve been trying to figure out what is happening with one of my LandCruisers and it’s about to drive me crazy. It’s a 97’ with 236k miles. When I got it a year ago and added a CDL switch. The lockers have always engaged almost instantly.

Not long after I started driving it regularly, I noticed the oil light would come on occasionally for about 30 seconds or so but the oil was never low. Around the same time I noticed that my center diff became finicky. No relay click or anything. It wasn’t trying to lock. I’m confident this is not a CDL position switch issue or fuse or anything like that.

Later on, when the weather got colder and wetter through the winter, the CDL started working again but I still got the oil light on occasion. That’s when I realized the two were related (see the linked video).

20181207_221730000_iOS.MOV

So then I did a little digging and found this:

And this:

Which makes me think it’s a bad ground or short on the E17 circuit.

Now that the weather has warmed up, the CDL has become totally unresponsive and the oil light comes on almost every time I drive it. I’ve poked around and tried to figure out where to go from here but I’m stumped. Is there a common failure point in the harness that could cause these issues? Anybody have any suggestions? Thanks.

 

[ppc]

The location of E17 shown on the illustration looks to be in or near the wiring harness that passes near the EGR. There are numerous reported problems where that harness comes in contact with the EGR damaging the insulation on wires, causing short circuits etc. as a result of a failed supporting clip on the firewall.

I would suggest dissecting the harness, making sure nothing has been compromised. If not your current problem you may be avoiding future problems by rewrapping the harness with a protective heat shield.

 

[Hawgleg]

Oh man...I didn’t think about the EGR. The harness looks fine with heat wrap intact on the outside but it is right against the hot pipe so who knows about the inside. I guess I should investigate further.

 

[ppc]

There are many reports with similar observations, "everything looks OK", only to find damage once the harness has been opened up.

 

[96LandcruiserPJ]

I think I have the same problem. I can not get the CDL engaged (not even a dash light) and I have frequently got the oil lamp coming on when oil level is fine. I would love to hear more about any resolution. Where is E17 in this photo? Since I can not get the CDL engaged, I assume that's why the front and rear diffs aren't locking.

 

[Hawgleg]

The E17 ground is on the back of the intake manifold near the arrow. I‘ve tried cleaning mine but it didn’t solve the problem. I need to set aside some time to mess with this further. I think the problem might be in the harness...

 

[Shipwreck]

I agree that electrical harness problems near the egr could be a likely cause.
In addition to peeling away the harness, I would also check the function of both the cdl position switch and the oil level switch. Both of those switches are common failure items. Removing and cleaning often cures them. While there is no cheap aftermarket replacement for the oil level sensor, there is a NAPA or Beck Arnley switch that is a direct replacement for the CDL or Diff Lock position switch.
See @george_tlc cdl write up:
CDL Sensor/Switch

 

[rolliges]

Both problems are common. There are so many systems, also, that share a common ground.

It is easy, but most likely incorrect, to suspect that they are related in any way.

Rule out the ground (remote) possibility and address each issue individually.

 

[Hawgleg]

I think it’s probably in the harness but I’m skeptical that it’s at the usual EGR melt spot. I don’t believe the oil position sensor or CDL circuit are found in that section of the harness. The E17 ground is on the back of the intake manifold and it comes from the underside of the truck. As far as I can trace, it never gets anywhere close to the EGR pipe. This is definitely not a case of the position sensor being bad, my CDL is not locking. I think cleaning grounds and checking voltage everywhere possible is a good place to start. I really don’t want to start hacking on my harness to see if it is damaged internally until I rule everything else out.

 

[Hawgleg]

Both problems are common. There are so many systems, also, that share a common ground.

It is easy, but most likely incorrect, to suspect that they are related in any way.

Rule out the ground (remote) possibility and address each issue individually.

Make sure to watch the video....I wouldn’t have ever thought they were related if it wasn’t for that.