106 dash warning lights

[woodhead722]

2002 106 1.5diesel. A few weeks ago 3 things happened together
1) Engine warning light displayed
2) Handbrake light constantly on
3) Rev counter packed up

I tested it locally & car seemed to be OK (wife uses it and I noticed everything when I used one evening).

Few days later, spluttered and I came back from our road end.

Took it to garage to have faults read - it got there on low revs.

1) Crank sensor
2)temp sender
Both at fault.

Both eventually replaced.

Mechanic said he hadn't made progress & could not cure. I tested and although light were off, they returned, first restart.

Runs OK, but don't understand what is going off. fault on computer now gives temp sender only, both lights on as previous, runs OK, no rev counter.

(I did hear of PUG electrics but have had for 20 years )

help appreciated, thanks

[spider]

Same unit as me the TUD5B, this has electronic timing control completely, the sensor between the delivery pipes measures this (same as the needle lift sensor on the 1.9XUD units) and adjusts the timing via the timing control unit also fitted. ECU atop the battery.

Check temp senders fitted to thermostat housing, there are two fitted. A fault in the right hand one (when viewing from engine bay so the nearside sender in effect passenger side) can cause a running concern as this is used by the ECU to determine engine temp and keep the timing suitable as these units do not have a cold start fast idle cable, they do sound horrific when stone cold though that's normal.

I'm 90% sure its the right hand one the other one drives the warning light only (single pin but two wires fitted in plug as its capable of having a gauge fitted but they don't have one on these late models)

It will run badly without any of the sensors connected in most cases although the timing will be all over the place.

What did they use to check for faults ? A Planet will show when its running what is going on ie timing asked for and what is being given. See pic:



If you have a fuel system full of air it can also really upset this system too. Its a Bosch pump. Examine the following areas:

On the injectors, check the leak off piping for splits and leaks, any air being dragged in here will really upset it. Pay attention to the end 'cap' on the last injector after the loop.

You'll see the clear fuel piping near the pump there's a section where you can see both feed and return (the one you see on the top of the pump on the 'extension' is the return. When its running are there any bubbles here ? Operate the primer (with it not running!) and look at the pipe for bubbles.

The other cause is the waxstat for the fuel heater (similar to the XUD one a white plastic spring affair) these can take air in. Its on the back of the filter housing so not easy to see. The 'usual' cure is a finger of sealant applied to its orifice, after checking its clean and dry, if there was a concern here with its o-rings (its not really possible to replace it easily) then this can fix it in most cases.

EGR valve, rarely gives problems on these though, pull the vacuum pipe from the valve to ensure its closed or just unplug the electrical connector on the bulkhead, this will *not* cause the warning light to come on.

Regarding it running OK, when its stone cold does it run at a sensible speed ? , these units don't really have a 'fast idle' to any degree. And when its warm after say five minutes running does it sound nice and not knocking to excess ? (a faulty sensor will do that as it will ignore and preset a timing setting)

[woodhead722]

Hi Spider, thanks for all your suggestions.

No apparent leak-off tube splits.

Some small bubbles in pulses from the fuel filter (?) to the pump.

Not yet looked for the waxstat, but the car ticks over OK when cold, sounds a bit noisy when setting off, but acceptable once warm.

Did not hear of any change when I pulled the tube off the EGR.

The right hand temp sender was the one changed (BLUE) it has 2 wires (same colours as GREEN one). There are 2 pins on both senders.

Apart from that, it's running OK, but lights still on - probably fail next MOT in Oct! Still don't know why REV counter packed up at the same time

[spider]

It could be the TDC sensor at fault although I seem to remember the sensor wire between the pipes will stop that too although it will run badly without that.

The noise when cold is normal, as long as it sounds good when its warm. It will probably not have a thermo cold start cable at this age like mine does not.

The filter wax stat, you will have to feel for it. If there are only tiny bubbles present then I doubt that is the concern as there are some in mine in the outlet if I prime it but never when it is running.

Really you need it plugged in to a Lexia (well Planet in this case) to get the real fault code out.

EDIT... The blue sensor is for the warning light and gauge if fitted (you won't have one at this year in most cases) some are single and some are two pin (the wiring is nearly always two wires)

The green sensor is for the preheat timer and ECU if this is unplugged (mine is at this moment while i test something) then the glowplug light and engine light will stay on for about 10 seconds then go off. You may have rough running when cold and reasonable running when normal. Don't do this as a test just trying to provide more info.