Bulk Workwear - Clothing Suppliers for the Whole Forum Network
This official sponsor may provide discounts for members

Discuss Desperate Van owner needs expertise in the The Welcome Forum area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:  American Electrical Advice Forum

Hi All,
I'm a working man relying on his van to stay in business - but of course it's developed a horrible electrical fault that needs more expertise than I can muster (I can do minor stuff ok). Vehicle forums have got me nowhere, so now I'm hoping you guys will be able to help:
I have a 55 plate Toyota Hiace 280GS with the 2.5 D-4-D engine. The van is low mileage (under 60k) and in excellent condition and I was hoping for a long life from it. However, on the day it passed its MOT and after a routine service, it failed to fire up. The engine turns over but the injectors are not firing. No warning lights show. So far the following has been done:

  • Earths checked and cleaned. Visual check made of all accessible contacts.
  • Fuel pressure checked in common rail and all ok.
  • Initial diagnostics suggested a fault or short in the EDU circuit.
  • ECU and EDU removed checked and passed ok by a specialist( they were even rigged to injectors which fired happily).
  • A check by an auto electrician showed a voltage spike in the ABS circuit. Removal of the relay saw the van fire and run, but only for a short time (presumably until the ECU had remapped the system?) The ABS was removed, checked and found fault free.
  • Further diagnostics suggested a fault in the canbus, with the resistance at one end of the canbus circuit reading 120 ohms and 0 at the other (it should be 60 ohms - two 120 ohm resistors in parallel reducing down to 60 ohms).
I have no idea what has caused this to happen so suddenly and don't really know what to do for the best, so I need somebody with an in depth knowledge of Hiace electrics or who has experienced a similar problem for some advice or thoughts please!
 
Scolmore Electrical Products
This official sponsor may provide discounts for members

DPG

-
Arms
Esteemed
I'd be concentrating on that incorrect bus resistance. Can you narrow it down in any way? Maybe disconnecting as many things as you can while monitoring the resistance.
 
  • Thread Starter Thread Starter
  • #3
I'd be concentrating on that incorrect bus resistance. Can you narrow it down in any way?
That's the frustration. All the wiring looks immaculate and there is no obvious damage point.
 
  • Thread Starter Thread Starter
  • #5
Often the problem. But disconnecting and testing would find faults that may not be visible.
Ok. That's a good start point, thanks. Is it likely that one of the can bus resistors would be down - i.e are they known to fail - or more likely that the resistance issue is caused by something failed in the circuit?
 

DPG

-
Arms
Esteemed
Ok. That's a good start point, thanks. Is it likely that one of the can bus resistors would be down - i.e are they known to fail - or more likely that the resistance issue is caused by something failed in the circuit?
I'm not familiar with CANbus so would have to look into it. Having said that, it seems likely that either a short circuit or a faulty component or sensor could be dragging the resistance down to zero Ohms.
 
  • Thread Starter Thread Starter
  • #8
I'm not familiar with CANbus so would have to look into it. Having said that, it seems likely that either a short circuit or a faulty component or sensor could be dragging the resistance down to zero Ohms.
Hopefully it's a component or sensor as you say - I'm not sure how I'd find a break in all that spaghetti!
 

DPG

-
Arms
Esteemed
Can you get hold of a wiring diagram?
 
  • Thread Starter Thread Starter
  • #10
are these resistors accessible or buried within the loom?
I don't know where the resistors are in the loom. My auto electrician felt they were embedded in the loom. Most modern vehicles have the resistors in the ECU (so I'm told), but my ECU has been tested off vehicle and is sound, so presumably so are the resistors if they are inside?
Post automatically merged:

Can you get hold of a wiring diagram?
Researching that - nothing obvious on the net, but hoping Toyota will be able to provide one.
 

DPG

-
Arms
Esteemed
But you are looking for a low resistance. This to me points to some other fault pulling the resistance down. Resistors don't normally fail by going low, they usually go high resistance. Not always obviously.
 
  • Thread Starter Thread Starter
  • #12
But you are looking for a low resistance. This to me points to some other fault pulling the resistance down. Resistors don't normally fail by going low, they usually go high resistance. Not always obviously.
A systematic check of components does seem the sensible start point from what you say. Thanks for the insight.
 
SuperlecDirect - ElectriciansForums.net Electrical Suppliers
This official sponsor may provide discounts for members

Reply to Desperate Van owner needs expertise in the The Welcome Forum area at ElectriciansForums.net

Top Bottom