DPF Sensor

[Old.Tony]

As described by Martin in this thread, you can do the reset by:

* Warming up the vehicle by driving it around for 30k. Even 10k might be enough.

* Stop the vehicle and write down the value in your trip meter (note 1)

* Remove the negative lead from the battery

* Turn your ignition ON (obviously you should not see anything happen) for 10 seconds, then off again. (note 2)

* Reconnect your battery negative lead to the battery and close the bonnet (note 3)

* Get back in, start the car and drive gently for a while, then shut the car down again.

You can use the pedal sequence in this post but it's not as simple as the above.

Notes:

1. You only really need to do this if you use your trip meter to help monitor fuel consumption. If you don't care, don't bother!

2. The goal is to discharge all of the power from the ECU so that it "forgets" everything. The ECU is supposed to "learn" while you drive, so that it improves performance, but like any "intelligent" system it invariably gets it backwards sometimes and we have the opportunity to fix this with this technique.

3. I strongly caution anyone, before considering connecting the negative lead to the positive lead, to test with a multimeter that there is NO voltage present across the two leads before doing so. If there is ANY power in the system, there is a risk that you can damage the ECU and everything from that point on is expensive. Make sure you have drained the power by turning the ignition on before touching the leads together - better still, don't bother touching them together, because by turning on the ignition, you've already drained the power.

 

[Jason]

Maybe a disclaimer about disconnecting any dual battery systems as well?

 

[Old.Tony]

Maybe a disclaimer about disconnecting any dual battery systems as well?

Excellent thinking, we've no idea if the isolators will fully isolate or will feed power in if the positive and negative leads are connected, for example. That would be a very expensive light show.

 

[Mintie]

Most modern diesels with an ECU have a fuse for the ECU. Would removing this fuse for 20 minutes allow the residual ECU charge to dispate enough to facilitate a ECU reset?

 

[Old.Tony]

Mintie, pop the fuse out and turn on the ignition. The (legitimate) circuit created will consume all of the power in the unit thus causing the reset within seconds.

Don't forget to make a note of your tripmeter, if you're using it for mileage calculations.

 

[KraftyPg]

Phew what a relief I saw this thread was active again and thought for a minute that my DPF was going to explode, stop the car, drink all my diesel, stop the ute from going into reverse or maybe just sprout horns and turn into a miniature satan but it's about the ECU. I can't tell you what a relief that is, I have trouble sleeping at night because of that blasted DPF and it's evil intentions, what were Nissan thinking installing it on my car.

 

[Pete22]

DPF warning light

I was always under the assumption that the DPF warning light would only come on following periods of slow/relatively slow driving. For example mine came on after 3 days of driving at speed <25kph on the Gary and Gunbarrel Highways last year. Locked the car in Low/Low, got the RPM up and after about 15 minutes the light went out......sort of like the book says it will except I couldn't get up to 80kph because of the bloody corrugations.

Now yesterday I'm travelling back on the Hume Highway from a run to King Valley to sample some of the great wines of that region......I was towing my Kanga Campertrailer (approx 1 tonne). Filled up with Shell fuel at the big truck stop just on the northern outskirts of Albury (took on about 100ltrs) Running up the highway and just short of Gundagai the bloody DPF light came on....huge surge and seems to drop significant torque. Took a break at Maccas in Gundagai for a coffee to re-read the manual and then back on the road.....turned the OD off and headed up the highway again and after about 15 minutes the light went out.

Happy with the burn....but what I can't understand is why the bloody hell the light came on in the first place as I was sitting on 100-110kph on the Hume......any ideas anyone????

 

[KraftyPg]

I've never heard about it only coming on at low speeds as far as I am aware it can come on at any time no matter what the speed because it has to do with a build of crap not just a build up of crap because your going slow. Slower speeds for longer may make it more likely but it's not just restricted to low speeds.

 

[Old.Tony]

You know, I've not had mine light up ONCE and I tow 1.8T around. I don't flog the thing, I let it crawl up to speed. Now I'm doubting that is it at all - not everyone is a jerry-hattrick!

There's a good chance one of your pressure sensors is having an issue. The thing is, after all, just a small sensor that modifies an incoming voltage. The DPF light is supposed to come on to indicate a problem if the pressure differential is too high AND the ECU has been unable to conduct a regen cycle without notifying you.

That raises another thought. Why has your ECU not figured it can do a regen when you are clearly giving it opportunity to? How's the needle on the temp gauge on your dash? Mine sits about a third of the way up, does yours sit higher? I'm wondering if your engine temperature sensor may be the culprit.

For those interested, the only requirements for the ECU to conduct a regen cycle is engine speed > 1600rpm (about 80km/h in top gear), engine load light and engine temp normal.

Towing 1 tonne should not make the thing think it's struggling, so my guess is one of the sensors is a little off-spec and is throwing the system out. I'd actually guess it's the engine temp sensor, because judging by the surge you experienced, the DPF was probably full and the ECU just never had gotten around to cleaning it up by conducting a normal regen cycle.

It may be worth whacking those sensors out and testing them. If you're going to do it, say so, I'll get the reference voltages out of the manual for you.

 

[Pete22]

You know, I've not had mine light up ONCE and I tow 1.8T around. I don't flog the thing, I let it crawl up to speed. Now I'm doubting that is it at all - not everyone is a jerry-hattrick!

There's a good chance one of your pressure sensors is having an issue. The thing is, after all, just a small sensor that modifies an incoming voltage. The DPF light is supposed to come on to indicate a problem if the pressure differential is too high AND the ECU has been unable to conduct a regen cycle without notifying you.

That raises another thought. Why has your ECU not figured it can do a regen when you are clearly giving it opportunity to? How's the needle on the temp gauge on your dash? Mine sits about a third of the way up, does yours sit higher? I'm wondering if your engine temperature sensor may be the culprit.

For those interested, the only requirements for the ECU to conduct a regen cycle is engine speed > 1600rpm (about 80km/h in top gear), engine load light and engine temp normal.

Towing 1 tonne should not make the thing think it's struggling, so my guess is one of the sensors is a little off-spec and is throwing the system out. I'd actually guess it's the engine temp sensor, because judging by the surge you experienced, the DPF was probably full and the ECU just never had gotten around to cleaning it up by conducting a normal regen cycle.

It may be worth whacking those sensors out and testing them. If you're going to do it, say so, I'll get the reference voltages out of the manual for you.

You might have it there Tony.....FYI my engine temp was, as always, like your's - gauge sits about one third of the way up the scale. I will keep an eye on things and get Mr Nissan to check it out next service. I suspect though that unless the computer tells them that there is actually a fault they won't be any the wiser.

 

[KraftyPg]

Your sig says you have a scangauge if it was installed at the time and the burn was anything more than a normal burn it could have picked up an error, check your error codes if you're concerned about it being anything else.

 

[Pete22]

Your sig says you have a scangauge if it was installed at the time and the burn was anything more than a normal burn it could have picked up an error, check your error codes if you're concerned about it being anything else.

Yep did run a scan and it came up with FRZD .....anyone know what that means. There were no other codes.

 

[Old.Tony]

Yep did run a scan and it came up with FRZD .....anyone know what that means. There were no other codes.

I googled that and it looks like frzd means that it has frozen data and you should be able to retrieve it. I don't know how.

 

[KraftyPg]

Is it in the manual? I don't know where my manual is right now but you'd reckon if the gauge comes up with such comments it would be referenced in the manual.

 

[KraftyPg]

The manual is online. FRZD supposedly only comes up when there is codes stored and pushing the button indicated by FRZD should give you information

If there are any stored Diagnostic Trouble Codes (DTCs), the number
will be displayed. An example screen for 2 stored codes would be:
2 Stored Codes
<CODES FRZD>
This selection can only be reached if there is at least one trouble code.
Pressing the button next to FRZD will show the data for each of the
Parameter Identifications Descriptors (PIDs) if data was captured when
the trouble occurred. The screen will allow you to step through the PID
numbers using the lower left and right buttons and see the available data.
Gauge values will be shown in the top line for those PIDs which directly
correspond to a gauge. The values in the second line are in hexadecimal
just as they are reported by the vehicle computer. You can exit this mode
using the HOME button.

 

[Pete22]

The manual is online. FRZD supposedly only comes up when there is codes stored and pushing the button indicated by FRZD should give you information

Yep did that Krafty and it came back with 'no stored codes' - go figure !

 

[KraftyPg]

Well going by their documentation if it says no codes were stored then the ECU didn't report a fault, (note this is going by their documentation only real world could be completely different).

Until Nissan prove otherwise I'd tend to agree with SG that there was no error and that it was just a regen. I've read the manuals for a few vehicles now that have DPF and apart from the Toyota one being a real bastard to do if it can't do it automatically none of them have suggested that regen will happen every time without the driver knowing or that any time the DPF light comes on there is any sort of error to go with it.