Help needed to understand Nanocom EVO Codes from my D2 Td5

Quote:

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Originally Posted by OffTrack

http://www.aulro.com/afvb/attachment...1&d=1382430954

Doesn't look like there is too much wrong in the recording, but unless you caught the conditions that are causing the fault it's not too surprising.

You can see track one and track two moving in opposite directions. The supply looks fine.

c4+c5 is track 1 and track 2 added together. They should be close to the supply voltage so there is a bit of discrepancy there. Not 100% sure what is acceptable in that regard.

Anyway it's not obviously bjorked, but that doesn't preclude an intermittent fault.

The fact that wobbling the wiring seems to have made an improvement bothers me. I'd be investigating the connectors and continuity in the harness just to make sure it's not a wiring fault.

Otherwise it's looking like a pedal change might be worth trying.

cheers
Paul

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According to the nanocom doc below you are allowed a +/- 10% difference between the supply and combined throttle 1&2 voltages before a fault is recorded.

http://web.nanocom.it/download/LUCAS...DIAGNOSTIC.pdf

Except at rest, your combined 1&2 voltages are about 5-6% higher than supply. I had a quick look at some logs I captured earlier in the year and for my D2a and the combined 1&2 voltages are consistently only 1-1.5% higher than supply and nothing below100%. So perhaps the pedal is on the way out, but only occasionally does it go beyond 10% and records an error.

Does any one know if the voltages be used to measure the degree of degradation of the pedal???

Regardless I agree with Paul regarding checking the harness and cleaning connectors first. Contact cleaner is your friend :)

Cheers

Steve

Thanks for the replies guys.I'll give it a thorough check tomorrow under the dash and through the firewall.I will also make sure that I spray the connector at the pedal with contact cleaner.Then try it all again and see what happens.;)
Cheers
Chris

Quote:

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Originally Posted by Rok_Dr

According to the nanocom doc below you are allowed a +/- 10% difference between the supply and combined throttle 1&2 voltages before a fault is recorded.

http://web.nanocom.it/download/LUCAS...DIAGNOSTIC.pdf

Except at rest, your combined 1&2 voltages are about 5-6% higher than supply. I had a quick look at some logs I captured earlier in the year and for my D2a and the combined 1&2 voltages are consistently only 1-1.5% higher than supply and nothing below100%. So perhaps the pedal is on the way out, but only occasionally does it go beyond 10% and records an error.

Does any one know if the voltages be used to measure the degree of degradation of the pedal???

Regardless I agree with Paul regarding checking the harness and cleaning connectors first. Contact cleaner is your friend :)

Cheers

Steve

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Good point on the variation. That has prompted me to have a closer look at the section of code that handles this.

At the point this is checked in the ECU the values of the track 1 and track 2 are in the range of 300 to 9700 ( voltage x 2000) . These should add to 10,000 if there is no deviation in the tracks. The ECU adds the two values, subtracts 10,000, then compares the remainder to +900, and -900 and sets a fault if the remainder is greater than this. So the allowable variation is -/+9% of supply voltage.


cheers
Paul

The other thing I would mention is that the checks are done on the track voltage scaled by the supply voltage. I haven't got quite as far as determining where the reported figures are derived but I am fairly sure the figures are effectively a straight conversion of the sensor voltage to required units. The actual figures used for range checking will be slightly different to what the Nanocom displays.

Interesting Paul,

So it does refer to the actual supply voltage and does not just use a nominal 5v to determine if it is in error?

Cheers
Steve

Quote:

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Originally Posted by Rok_Dr

Interesting Paul,

So it does refer to the actual supply voltage and does not just use a nominal 5v to determine if it is in error?

Cheers
Steve

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Sort of ;)

The Track voltages are corrected by the difference between the actual supply voltage and 5V, and the error is then determined as a deviation of the corrected voltage from 5V.

The actual calculation is:

Track Voltage (mv) x 10000 / Supply Voltage (mv)

If you had track voltages of 4.2v and 0.8v and a supply voltage of 4.9V:

Track 1 = 800 x 10000 / 4900
Track 1 = 1632 ( 2 x 816mv)

Track 2 = 4200 x 10000 / 4900
Track 2 = 8571 ( 2 x 4285mv)

The track consistency check is then:

(Track 1 + Track 2) - 10,0000

So
= (1632 + 8571) - 10000
= (10203) - 10000
= 203

This figure then checked against +/-900 and a fault logged if the difference exceeds this figure. 900/10000*100 = 9%.

From what I can tell diagnostic tools report the "raw" voltages pre adjustment for supply deviation from 5V.

FWIW the reason for the x2 of the voltage is to simplify the math which increases the speed and precision of the calculations done by the ECU.

cheers
Paul

Right....... Thanks for the explanation Paul. I'm glad you can decode it all :)

Makes sense but a different way of skinning the cat.

Cheers

Steve

I'm glad you guys know all about this.I have no idea what you guys are talking about:D:D. OK a bit of another update.I disconnected the plug to the TPS and gave it a clean with contact cleaner.I also checked the loom through the fire wall for rubbing but it all looks intact.I have only done a few kilometres of driving but it seems to be fine again.

I don't particularly know what to do from here.Do I just replace the TPS and hope that was it? Or do I keep driving it and risk it stopping in traffic to see if the problem occurs again? By the way do you just replace the TPS or is it the whole pedal assembly that you have to change? Sorry for the dumb question guys:confused:

Thanks
Chris

The tps is part of the pedal unit so you need to replace the whole unit.

Well its been awhile since I have updated this thread. A lot has gone on in the past month. I haven't driven the Disco much and it is still having the same intermittent missing problem. It has been sitting under the car port not doing much while I can sort out what's wrong with it.

It's looking like I will have to replace the TPS but cash is short at the moment.:( Does anyone know where I can source a good second hand one at a decent price? PM me please if you do.

Cheers
Chris