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Limp Mode

Barras

By Barras,
in Four Door Family & Wagoneers

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bigkevracer Grand Master

bigkevracer

Posted
Posted

I seem to be having the same problem, except more intermittent.

Car threw a code on the dyno for TPS, without completely killing the throttle.

I didn't have great throttle response afterwards, but the throttle _always_ worked.

We cleared the code, throttle response was better.

Now twice in the last few days it has suddenly lost all throttle response, just idles. This wasn't on WOT or taking off, just normal street/highway driving. I pull up ASAP, turn the car off, turn it immediately back on, and throttle is fine.

No code clearing, no mucking about: Goes bad, turn off, turn back on, goes good.

I think it could be one of four things:

  1. TPS sensor - most sensible thing given that's the code it threw
  2. Cruise control, which has a T piece in the throttle - both times it's happened so far I've had the cruise control on and I've either been using cruise or just turned it off
  3. F-con throttle map
  4. Throttle wire on the ECU, where I had to splice in the wiring for the EVC

None make sense to me given the weird behaviour. I'm thinking of disconnecting the throttle T-piece for the cruise and seeing how it goes. If it continues, replace the TPS sensor.

Anyone else noticed anything similar?

scotty nm35 Grand Master

scotty nm35

Posted
Posted

I had to disconnect a cruise the other day for the same fault, I have also seen the throttle assembly being the issue. (tps)

Mine did the same thing with the pivot throttle controller plugged in, any resistance difference between the two throttle signals will trigger limp mode.

Try disconnecting the cruise for a while, it may well be the answer.

Daleo Grand Master

Daleo

Posted
Posted

I seem to be having the same problem, except more intermittent.

Car threw a code on the dyno for TPS, without completely killing the throttle.

I didn't have great throttle response afterwards, but the throttle _always_ worked.

We cleared the code, throttle response was better.

Now twice in the last few days it has suddenly lost all throttle response, just idles. This wasn't on WOT or taking off, just normal street/highway driving. I pull up ASAP, turn the car off, turn it immediately back on, and throttle is fine.

No code clearing, no mucking about: Goes bad, turn off, turn back on, goes good.

I think it could be one of four things:

  1. TPS sensor - most sensible thing given that's the code it threw
  2. Cruise control, which has a T piece in the throttle - both times it's happened so far I've had the cruise control on and I've either been using cruise or just turned it off
  3. F-con throttle map
  4. Throttle wire on the ECU, where I had to splice in the wiring for the EVC

None make sense to me given the weird behaviour. I'm thinking of disconnecting the throttle T-piece for the cruise and seeing how it goes. If it continues, replace the TPS sensor.

Anyone else noticed anything similar?

I have just had this happen on mine too, throttle hasn't failed, but response is really lazy below 3000 rpm, with basically no boost.

I actually thought it might've been a camshaft position sensor.

Reset once, was fine for a couple of days, then lazy again. Reset, but noted the code, which was 1705; throttle body.

I'm running cruise control also, but I have been for well over a year now with no issue. I don't think that's the issue.

Going to have a poke around tomorrow, check plug & pins are clean & plugged in; but I would think the next step is a spare known tb to see whether it returns.

I'd be interested to hear what you come up with Ryan.

bigkevracer Grand Master

bigkevracer

Posted
Posted

Cheers guys.

I'm with you Dale, don't think it is cruise control. Doesn't make sense after a year of fault free running.

On the other hand it is the easiest thing to test, and of Scotty thinks it could be a signal problem I'll give it a try.

Just weird the problem didn't appear until the fcon went in...

Daleo Grand Master

Daleo

Posted
Posted

After another look at the fault code listing, mine is actually; P1705 Throttle Position Sensor Circuit A/T

This could also explain why mine didn't want to kick down, or unlock the converter with a small throttle input.

I might be looking elsewhere...

bigkevracer Grand Master

bigkevracer

Posted
Posted

After another look at the fault code listing, mine is actually; P1705 Throttle Position Sensor Circuit A/T

This could also explain why mine didn't want to kick down, or unlock the converter with a small throttle input.

I might be looking elsewhere...

Easiest thing is to replace the sensor though, or that's what my thought was...

Commsman Veteran

Commsman

Posted
Posted

You've had some stuff going on with your car lately, hey Ryan.

I also don't think it's the cruise as mine hasn't given me that problem either (although I don't drive it much ;) ), but like you say - it's easy to rule out as it only takes a minute to unplug the throttle harness.

If the fault appears semi-regularly now, it shouldn't be long before you know. Hopefully it's not the F-Con but a TPS as that's means the F-Con is OK (as the last 'electrical' mod you've done it has to be high on the list of possibilities). It could also be the cruise control interacting badly with the F-Con, but I don't know anything about how they wire in so just throwing it out there...

The timing of the fault is a bit of a coincidence with the F-Con going in though, & I have a hard time believing coincidences, so good luck with the fault finding.

bigkevracer Grand Master

bigkevracer

Posted
Posted

I have Leon, although most are my own doing so can't entirely blame Mr Nissan.

I find it hard to believe it would be the F-con, but like you said it is one of the last electrical mods. Scotty has been running the F-con with the cruise for a while now without issue, and I also find it hard to believe it'd be the mapping for the throttle in the F-con if the throttle completely dies.

They wire in by plugging in between the ECU plug and the ECU, entirely piggy back, except for a MAP and IAT sensor harness in my case.

Daleo Grand Master

Daleo

Posted
Posted

dale, I have a spare TB and pedal sensor if you want to try them on your car for a few weeks

Thanks Iain! I'm going to see if it comes back this week, and I'll be in touch.

I still have to get the name of the shade sail place for you too.

Cheers, Dale.

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