TPS / P0120 / Limp Home / 3k rev - possible fix

[oliver9523]

I'm probably going to tempt fate writting this but here goes...

A few months ago I was getting the p0120 EOBD code, my 02 ph2 172 was going into limp home every couple of days and less often it would do the thing were the engine would stick at about 3k rpm and the throttle would be completely unresponsive until i'd turn the car off and faf about with things, then it'd start working again.


First 'fix':
I got a 2nd hand TB from the bay of e, reset things and turned the check engine light off. It appeard to fix it, it lasted about 5 days before it went into LHM again and sometimes the 3k rev sticking.


Second 'fix':
This time went down the route of a new throttle pedal, this did much the same, fixed it for 4-5days then bang... LHM


Third 'fix':
Bit the bullet and took it into RenTec in Edinburgh (not a typo it is rentec without an 'h') they plugged the renault clip in and it was coming back as a fault on the aircon sensor, thought it might be pulling the 5v line that the sensors run off down to ground and messing things up. But about a week later...you guessed it...LHM ;(


Fourth fix:
The main battery cable runs through the same loom as all the sensors going into the ECU. So their next thing to try was to split the throttle body wires from this bundle and run it a different route to the ECU. This helps clean up the signals and stop any interference.

I'm on week 3 now and it's running a treat... even if it does go again this has been the longest a 'fix' has worked for, it has made a massive difference. Time will tell if it's a complete fix!


Brian at RenTec in Edinburgh is a legend, really friendly, knew his stuff and prices were pretty good too!

 

[jack_kemp]

Why would anyone think that it was a good idea running the battery wire with the rest of the wiring loom????

Is this normal?

 

[The Boosh!]

Hmmm... Actually I think that there could be a connection with this.

When ever my limp mode comes on (fairly seldom when it does), if you turn the ignition on and off fairly quickly, the fuel gauge warning light comes on, even when i've got a full tank of fuel, and the gauge confirms I have a full tank of fuel.

IIRC, the fuel light being on error is something to do with the battery as well.

 

[oliver9523]

I know, it seams pretty nuts bundling them all together with the battery wire! French eh?!
So who's feeling nervous about sharing an aircraft carrier with them?

I wonder if any other intermittent electrical faults could be attributed to this....

 

[Ol’ Tarby]

Hmmm... Actually I think that there could be a connection with this.

When ever my limp mode comes on (fairly seldom when it does), if you turn the ignition on and off fairly quickly, the fuel gauge warning light comes on, even when i've got a full tank of fuel, and the gauge confirms I have a full tank of fuel.

IIRC, the fuel light being on error is something to do with the battery as well.

i also sometimes get that mate. say if you stall at a junction and quickly turn ignition off and re-start, the fuel light will come on and stay on even though theres plenty of fuel in the tank

 

[andyparf]

hi i am a independant garage and have spent time repairing lots of renaults i have had this fault on a sport that took me ages to fix and was very intermitent

mine was lossing the 5v referance to the throttle body and other sensors under the bonnet bringing up verying different fault codes on the one i repaired the wiring from the map sensor was being rubbed through about 2 to 3 inches from the sensor plug, just where the rocker cover touches the wires it had rubbed throught on the underneath of the wire

i think green is 5 volts at map sensor but i can check

 

[ianysm]

Had this problem for about a year and finally have fixed it. I've done all of the above including numerous throttle body cleans/resets etc but it too only lasted about a week before playing up again.

Mine was due to two things;
I found some chaffed cables at the ECU plug and around where the plastic engine cover is around the engine which couldn't have been helping matters and would only have got worse.

but the main fix was due to corrosion in the engine compartment fuse box (next to battery). Water had got in there and made the fuses and relays pins green and corroded. Took each one out and cleaned and added WD40 and its been perfect since (that was about 5000 miles ago!)

Hope this helps

 

[oliver9523]

I'm dredging this thread up from the depths because the stupid thing has gone again

It had been fine since Nov 2010 but today out of nowhere, bang, the coil pack light [~] comes on and I'm back with limp home mode.... again.

Having read numerous threads about the same issues there doesn't appear to be a definitive answer. See my first post at the top to see what I've done so far. I think it's time to go hunting for chaffed wires next and clean my fuse box!

 

[NorthloopCup]

If it doesn't rev above 3k try changing the vvt solonoid. Seen this cause the very same fault your getting now.

 

[oliver9523]

Cheers, I'll take a look at the vvt solenoid, that's a new solution I've not come across yet.

Update: It did it again this morning after being sat for a couple of days in the pouring rain, I'm thinking it must be water ingress somewhere.

edit: it did it just by turning the ignition on this morning, normally it goes when driving

 

[bmh.01]

Cheers, I'll take a look at the vvt solenoid, that's a new solution I've not come across yet.

Update: It did it again this morning after being sat for a couple of days in the pouring rain, I'm thinking it must be water ingress somewhere.

edit: it did it just by turning the ignition on this morning, normally it goes when driving

Check the skuttle drains and the engine/dash connector in the righthand side of the skuttle behind the washer bottle. Make sure water isn't working its way up the loom and into the back of the engine side plug amongst other things.

 

[jack_davey]

What fault codes are you getting (apart from PO120)?

 

[bmh.01]

Me? None, I haven't got a clio anymore .

 

[Clio172NE]

Hi..sorry for dragging a thread from the depths of the forum but this came up when I did a forum search.

Needless to say im have limp home mode problems but mine (at the moment) only seem to happen with wide open throttle in 3rd (overtaking for instance, which is scary when you lose bloody power on the wrong side of the road!)

First time is restricted power but was still able to drive, second time no throttle response so coasted to a safe place with the revs stuck at around 2,100, revving to 2,300, back to 2,100 and so on and so forth with no input. True enough killed the engine, started back up and no problems.

Scanned it with handheld scanner and no fault codes (maybe wants a proper scan to bring anything up mind)
Not tried to fault find yet as it only happened yesterday and now im back at work but first port of call is to go wire chasing

 

[STEVE.M]

Hi..sorry for dragging a thread from the depths of the forum but this came up when I did a forum search.

Needless to say im have limp home mode problems but mine (at the moment) only seem to happen with wide open throttle in 3rd (overtaking for instance, which is scary when you lose bloody power on the wrong side of the road!)

First time is restricted power but was still able to drive, second time no throttle response so coasted to a safe place with the revs stuck at around 2,100, revving to 2,300, back to 2,100 and so on and so forth with no input. True enough killed the engine, started back up and no problems.

Scanned it with handheld scanner and no fault codes (maybe wants a proper scan to bring anything up mind)
Not tried to fault find yet as it only happened yesterday and now im back at work but first port of call is to go wire chasing

Don`t replace/buy anything,99.9 % likely to be loom corrosion,water ingress.Take it to Mick at Diamond Motors,he should sort it same day,for less than a stab in the dark throttle pedal.He did mine,and I am really gratefull.