27 replies to this topic

[ant1]

Hi,

need some advice please,

 

2003 NA, had pre cat removed several years ago.

 

Car developed an engine management light a few weeks ago. Brought a cheap code reader and get a P0141 fault. So I took a guess that one of my 2 lambda sensors were knackered.

 

Luckily I had a spare rear exhaust box that was given to me a year ago, so I changed over the sensors from that trying all the combinations and resetting light, 1 at a time then both together. But each time after about 20-40mins driving fault light comes up again, and occasionaly a P0140 pops up.

 

So this is my dilemma, I guess the other lambda sensors from the spare exhaust could be faulty as well.

 

So which sensor should I replace with a new one? possibly the one nearest to the tight exhaust bend( nearest to exhaust tip).

 

Or

 

Is there something else wrong with the poor VX?

 

Help, Any ideas before I start buying a lambda sensor, p.s. where's the best place to get one?

[woody91]

The fault codes relate to heater circuit malfunction. Id say your best option is to have someone read the live data on the ecu with something like tech2 or op-com(if this reads the live data) to determine whether its a lambda fault or something else otherwise you could be 1. wasting money on parts and 2. looking in completely the wrong place for the cause of the fault. Just obviously make sure the connections are clean and there are no obvious breaks in the wiring. Hope this helps.

[vaux2008]

It's usually the second lambda to throw up a code. Have you got a standard exhaust system? Also check for leaks from any of the flanges as leaks can also confuse the lambdas. Adam

[Exmantaa]

P0141 fault = heater circuit sensor 2; so the post cat lambda.

Replace rear O2 sensor or your the wiring is faulty. Check this first.

[Mangham54]

Check the sensor with a multimeter, testing for resistance. You will need to match the pairs of pins (as there are 4), but if you find both pairs have resistance then it is either not plugged into the correct socket, or the problem is between the ECU and end of your loom.

[ant1]

Cheers for info will check sensor resistance. So I guess if I get resistance sensor is ok. So then I need to check that the loom of doom plugs etc.

[Mangham54]

Resistance is what yoi want /need. 0 resistance suggests a broken wire / defective sensor. If I can find my thread ill post it up

[ant1]

Mangham54, Yes please dig out the post if you can...ta

[slindborg]

you want to see about 15Ohms on one pair (the heater)

the other pair... hmm not sure.

 

I am just prepping the data to build another batch of post cat sensor cheaters

[RobNA]

I have the same fault code. And one other one too. How much do the cheaters cost Stu?

[drunknmunky]

I understand a cheater means you can decat safely and I'm presuming its a cheaper fix than buying a sensor, but what does it actually do to the fuelling if anything? Would it pass an mot with a) a cheater, and a cheater and decat?

[drunknmunky]

The smiley was meant to be question b!! Not a smiley!

[drunknmunky]

Just found the answer to my own question in a more thorough search, sorry ignore my post please!!

[slindborg]

for others reference,

 

it does nothing for the fuelling, the post cat sensor is simply to detect that the cat is a) there and b.) working.... it bears no effect on the running of the engine.

 

MK2 cheaters should be between £20 and £30 depending on BOM costs etc.

[RobNA]

  MK2 cheaters should be between £20 and £30 depending on BOM costs etc.

Yes please. When do you think they will be ready?

[slindborg]

sometime this century

[Mangham54]

Mangham54, Yes please dig out the post if you can...ta

 

Here's the thread: http://www.vx220.org...69-p0141/page-2

[ant1]

Update: both lambada replaced one at time. (With the eBay £20 ones) and still throws up the same fault after near enough the same distance/ time. So after several different variations of lambda I think it's time to rule that out...... So what else could be throwing up a fault? Possible manifold cracked? Plugs need replacing? Help getting frustrating now! Ps car still drives ok.

[techieboy]

It's not an emissions related error, so leaks/plugs/whatever don't matter. It's saying the heater in the lambda isn't working, so if it's not the lambda itself, it must be the two wires that feed the heater part of the lambda. Have you plugged the sensor into the correct plug? There's an identical but unused one on the loom of some NA's.

[slindborg]

Or the cheap eBay sensors are doing what they do best....