Engine check light on 1999 V70 2.5D (UK)

Discussion in 'Volvo V70' started by Bonnet Lock, Nov 17, 2005.

  1. Bonnet Lock

    Bonnet Lock Guest

    With the curent cold weather, my (diesel) V70 (old shape) has been running
    very rough for a bit after a cold start - so I suspected that the glow plugs
    may not be operating.

    This morning, before trying to start the engine, I checked all the relevant
    fuses and relays in the main fusebox - to make sure that the fuses were
    seated properly, and not blown - and the relay operated ok (when it was
    removed and 12v applied to its coil).

    In the course of my investigation, I was curious to know whether the
    glowplug light on the dash indicates that the plugs are *really* on - or
    simply that the system *thinks* they're on. I turned the ignition on with
    the 15A fuse and relay removed, so that the plugs couldn't possibly
    operate - but the light still came on!

    I didn't find anything obviously wrong, and put it all back together - after
    which the engine started and ran perfectly normally - with none of previous

    *However* the engine check light is now on, and refuses to go off. I suspect
    that this was caused by turning the ignition on with the fuse out. The same
    fuse feeds the emission control equipment. I guess that an error code was
    generated, and will continue to turn on the engine check light until it is

    Does this sound likely, or is it indicative of something more sinister? Is
    it a trivial (and cheap!) job for a dealer to reset it? Presumably there
    isn't a DIY way of doing it without access to OBD-II equipment?

    Bonnet Lock, Nov 17, 2005
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  2. How long has it been on? I believe the Volvo ECUs are designed to turn the
    light back off if they don't detect the same fault again within a certain
    combination of time, miles and starts.
    Ernest Scribbler, Nov 18, 2005
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  3. Bonnet Lock

    Bonnet Lock Guest

    In an earlier contribution to this discussion,
    It's done it for 24 hours, during which I've done about 6 starts and 25

    Are you suggesting that it may sort itself out after a few more
    Bonnet Lock, Nov 18, 2005
  4. Bonnet Lock

    Mike F Guest

    If the problem is gone, it should reset itself after 3 complete check
    cycles - on my '98 this is 3 trips to or from work, which is about 25
    miles and 30 minutes. Short trips do not allow complete check cycles
    and won't contribute to turning off the light.

    Mike F.
    Thornhill (near Toronto), Ont.

    Replace tt with t (twice!) and remove parentheses to email me directly.
    (But I check the newsgroup more often than this email address.)
    Mike F, Nov 18, 2005
  5. Bonnet Lock

    Bonnet Lock Guest

    In an earlier contribution to this discussion,
    Thanks- that's encouraging!

    Do you have a feel for the minimum length of trip (time/distance) which
    would count? [Presumably less than 25 miles, but more than the 6 mile trips
    which I have done recently].
    Bonnet Lock, Nov 18, 2005
  6. Bonnet Lock

    mark Guest

    The heater plugs won`t affect running after starting.They are only
    energised for a few seconds prior to starting.My wife`s 850 2.5 TDI`s
    heater plugs are not working although the light still comes on as
    normal,but the engine starts first time.On the other hand one of our
    vans (Peugot) whose heater plugs are working perfectly will not start
    on a cold morning even with a burning newspaper held in the manifold.
    mark, Nov 18, 2005
  7. Bonnet Lock

    Don Guest

    I have a 1999 V70. The ETS (Electronic Throttle Control System) light comes
    on after the car hasbeen running for about 15 minutes. The car runs
    smoothly. My mechani says the electronic brain needs to be replaced or the
    ngine will start to run rough then perhaps have trouble starting. Any
    suggestions for next steps I should take? Do the Volvo dealers have a
    diagnostic machine which specifically diagnoses the problem?
    Don, Nov 20, 2005
  8. The dealer has a computer with special software and a proprietary interface
    device to read diagnostic information from your Volvo. It will tell the
    technician which signal caused the fault light to come on, and if he's
    competent, he'll be able to trace that signal back to the faulty component.
    (The dealer will typically expect you to be very generous in compensating
    him for providing this service.)

    In ETS, the ECU (engine control unit) gets position signals from a pair of
    sensors attached to your accelerator pedal and uses that information to
    generate a signal telling the throttle unit on your engine to adjust its
    position accordingly. I would suspect moving parts, like the position
    sensors, before electronic parts like the ECU. Since everything appears to
    be working normally, it may be that one of the position signals is faulty
    and the ECU is complaining about the lack of redundancy.
    Ernest Scribbler, Nov 20, 2005
  9. Bonnet Lock

    Bonnet Lock Guest

    In an earlier contribution to this discussion,
    Not so! The following is the description given in VADIS of the glowplug
    operation on the 2.5D engine:
    If the ignition is switched on when engine temperature is below +5 °C, the
    glowplugs are activated for a period which varies with engine temperature
    and atmospheric pressure. The glowplug indicator lamp on the dashboard
    indicates that preheating is active. Preheating shuts off when the engine is
    turned by the starter motor.

    Stand-by heating
    After preheating stand-by heating is activated for up to five seconds. This
    corresponds to the time between the glowplug indicator lamp going out and
    the engine starting. This makes the engine easy to start even if it is not
    started as soon as the indicator light goes out.

    Start heating
    Start heating is activated for up to 30 seconds each time the engine is
    turned over by the starter motor, if the engine coolant temperature (ECT) is
    below +30 °C and engine speed (RPM) is below a given threshold. Start
    heating facilitates engine starting even when it is not entirely cold.

    Post-heating starts when the starter motor stops turning the engine.
    Duration depends on engine temperature, engine speed (RPM) and quantity of
    fuel injected. Post-heating is always shut off when engine speed (RPM)
    exceeds 2500 rpm, irrespective of engine temperature and the quantity of
    fuel injected. Post-heating is always activated even if preheating has not
    been activated. This improves combustion which reduces noise levels,
    improves idling and reduces exhaust gas emissions. Post-heating also
    improves idling at extremely low temperatures.
    Bonnet Lock, Nov 20, 2005
  10. Each time my V40's MIL light has come on, (three times that I can remember)
    it's gone off again in about three work days. I drive 25 miles each way to
    and from work and usually drive a mile or two for lunch. This is strictly a
    guess, but there's probably something built into the algorithm to allow it
    to decide that the light should turn off after some number of short trips or
    even a single very long trip. It would make sense to have it that way to
    accommodate different use patterns, but all I can say for certain is what
    I've actually seen for myself, so don't take my guess as anything remotely
    authoritative. At any rate, I'd say that if your light doesn't go off within
    a couple of weeks under just about any driving conditions, you probably have
    a real fault somewhere keeping it on.
    Ernest Scribbler, Nov 21, 2005
  11. Bonnet Lock

    Mike F Guest

    I'm not aware of the minimum trip, but I know it requires some constant
    speed driving for several minutes, and some periods of idling after
    warmup where the A/C does not come on. It seems that my trips to and
    from work are ideal for this.

    Mike F.
    Thornhill (near Toronto), Ont.

    Replace tt with t (twice!) and remove parentheses to email me directly.
    (But I check the newsgroup more often than this email address.)
    Mike F, Nov 21, 2005
  12. Just ran across this in VADIS for my V40. (I'm much too lazy to check and
    see if it applies equally to other cars.)

    "If a fault disappears for any reason after the diagnostic trouble code
    (DTC) has been permanently stored in the control module, information about
    the fault remains in the control module for a while. For each diagnostic
    trouble code (DTC) stored, a counter records the total number 'fault-free'
    operating cycles since the diagnostic trouble code (DTC) was stored. If the
    control module does not register the fault after 10 completed operating
    cycles, the diagnostic trouble codes (DTCs) are erased automatically. They
    are 'self-erasing'."

    "An operating cycle is defined as where the ignition has been switched off
    and then on again and the vehicle has then reached a speed in excess of 30
    km/h. The ignition must have been on (or the car driven) for longer than 5
    Ernest Scribbler, Nov 25, 2005
  13. Bonnet Lock

    Bonnet Lock Guest

    In an earlier contribution to this discussion,
    Thanks, that's useful. I have a copy of VADIS, but haven't come across that
    information for my V70. Can you please tell me how you got to it for your
    V40 - and I'll follow the same route?
    Bonnet Lock, Nov 25, 2005
  14. Selected Function Area: Electrical System
    Selected Information Type: Design and Function
    Topics: 38 Instrumentation
    Diagnostic Functions ->
    Combined instrument panel diagnostic functions ->
    Diagnostic trouble codes (DTCs)
    Ernest Scribbler, Nov 25, 2005
  15. Bonnet Lock

    Bonnet Lock Guest

    In an earlier contribution to this discussion,
    Thanks. I've found the information you referred to for the V40 - but
    unfortunately, the equivalent V70 section doesn't contain any of this stuff.
    Bonnet Lock, Nov 25, 2005
  16. Are you using a politically conservative newspaper or a liberal one?
    .................................................., Nov 27, 2005
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