Engine check light on 1999 V70 2.5D (UK)

"Bonnet Lock" wrote

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.

It's done it for 24 hours, during which I've done about 6 starts and 25 miles.

Are you suggesting that it may sort itself out after a few more days/starts/miles?

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.

In an earlier contribution to this discussion, Mike F"

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. regards,Mark.

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" wrote

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.

Not so! The following is the description given in VADIS of the glowplug operation on the 2.5D engine: __________________ Preheating 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 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" wrote

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.

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.

"Ernest Scribbler" wrote

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 minutes."

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" wrote

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)

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.

Are you using a politically conservative newspaper or a liberal one?