Technical P1135 / u1602

[jazzjunkz]

Hi,

Since I bought my Punto in September 2011 - I have had an engine management light stuck on. After I bought the car I took it back to the dealer to check it out and reported that the o2 sensor was flagging up. He cleaned the sensor, cleared the code and sent me on my way ensuring everything should be fine.

Approximately 48 hours later - the light reappeared. The engine ran fine and the only thing I could notice was that the revs were fluctuating slightly on idle. (not enough for the rev counter to move though) - So I put it down to the weather.

Anyway, a month or two later I couldn't start the car. The AA came out and said that I needed a new battery (totally irrelevant). Whilst dealing with this he kindly put in his ODBII reader and found the code of 'P1135'. Told me it was an issue with the lambda. Looking online confirmed this.

A few weeks later - I booked this into a local garage for a service with the lambda in mind. They were happy to replace the lambda for £55. Lambda replaced, I thought everything was running fine. However, again, 48 hours later the light reappeared.

I borrowed one of my friends ODBII reader and the code output was indeed again 'P1135'. I also noticed the code of 'U1602' also.

On further investigation I have found the below:

P1135 = "Oxygen sensor heater resistance Bank 1 (Pre-cat)". It doesn't neccessarily mean you need a new sensor. It's never a good idea to just replace the component mentioned in a fault code definition without further diagnosis.

Pre-cat means the sensor before the cat so you didn't need to replace the second sensor. Assuming your new pre-cat sensor is working and you have joined the wires correctly, it's likely that there is a problem with the heater wiring from the sensor.

+

"U1602 - CAN Data Bus - communication error probable cause:-

Wiring, poor connection."

Now from the above. It makes me think that either the garage haven't replaced the sensor at all, or that they have not fit it properly or perhaps even damaged something.

I am going back tomorrow to the garage to see what else they can do for me regarding this but should I be looking elsewhere? I know the spark plugs were replaced on the service. Could it be possibly damage to the exhaust?

Reading around the forum. I noticed if this code was in addition with another code then it it'd be likely that it was something else. But it seems to be pointing in only one direction.

If anybody else could shed any light on this or be of any assistance I would really appreciate it.

Thanks,
Jared.

 

[fingers99]

It could be that they fitted a "universal" lambda and didn't do the connections properly -- they can be very difficult to do, which is why -- more expensive -- OE ones are to be recommended.

£55 is damn cheap if it includes fitting.

The canbus error is likely to be something entirely different.

 

[Brendan W]

Took the words out of my mouth. Would have expected a genuine one to cost double that. Think they may have been fobbing you off from day one when the sensor should have been replaced.

 

[jazzjunkz]

Well £55 was the price for the sensor. The actual labour for the service excluding parts was £70 (the total service inc. lambda was £225) - so I would assume somewhere the fitting of the sensor was within that somewhere.

They didn't show me the old lambda. They basically gave me the paperwork and that was the end of that really. They did give me an advisory on the front brake discs+pads, but took my money and away I went.

I'm going to take the car back in tomorrow and challenge them on this.

I was naive to think that the problem from the beginning was going to disappear - but I've only learnt from it. It was the first car I bought and luckily there aren't any other mechanical/electrical problems...yet *touches wood*.

 

[GranDuke]

I had a crack in my exhaust manifold, OBD2 told me it was precat o2.

Using same o2 sensors now, and it's OK.

 

[zigleon]

Had a similar problem with my Sporting....put in a universal sensor and the car didn't like it one bit. Light came back on within 2 days.

Changed it for a genuine Fiat one....problem solved.

 

[jazzjunkz]

Thanks for the comments.

I went down to the garage that fitted the sensor. It looks like they removed the wrong sensor. The error reports to the pre-cat sensor and they removed and replaced the other one. I've rebooked the car in for Monday. To say the least, I am pretty annoyed. I am hoping that they will still have my previous WORKING sensor and then just replace the NON WORKING sensor with the one they replaced.

Sigh.

 

[Brendan W]

At this stage I would have a close look at the cat and check that a new sensor has in fact been fitted downstream and if the wiring appears to have been modified. Then ask the garage what exact sensor they intend to use precat , if that will involve wiring mods and, if they are going to refit the old post cat unit will that involve un-modifying the wiring and if that could give rise to communication errors.