Hi, at the start of the week the amber engine warning light came on, I read the fault code and it was P0130, which after some research i found out was the pre-cat lambda sensor.
I changed the sensor, cleared the fault and everything was fine....for 3 days. Now on the way home from work the amber light has come on again this time with fault code P0135. Which I believe is also related to the pre-cat lambda sensor.

Does anybody have any ideas?

BTW it's a 2004 1.2 8v punto

Thanks

there are million topics on this error code P0135
try typing P0135 in search

https://www.fiatforum.com/punto-ii/337862-lamba-sensor-open-circuit-problem.html

When you changed the sensor was it a used part, genuine Fiat new or generic new and did you have to get creative wiring it up?
Both codes refer to the precat sensor and it's heater cct.
Used sensors tend to have failed heaters, if the wiring had to be redone that also can cause problems.

The lambda sensor was bought new from euro car parts, it has the right connector plug, so no butchering of the wiring.

http://www.obd-codes.com/p0130
02 Circuit Sensor Malfunction - Bank 1 sensor 1

Its saying there is a wiring fault of some sorts

http://www.obd-codes.com/p0135
Oxygen O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)

Since you put a new sensor in - this is code is the most likely cause
The new sensor should a resistance across pins 3 and 4 - 10 Ohms resistance

Autodata lists 2 codes for p0130 tho... p0130 is the same p0135 - relating to heat element fault


My advice is this

Check the connection on the engine bay wiring loom isn't crappy filled with gunk
I'd spray some Wd40 or something like that into the connector - connect and disconnect a few time (like 5 or 6)

Clean it with some more spray oil - shake excess out - fit back together


You can also swap the Pre and Post sensors around, they are the same
See what fault is developed then
if the fault goes to Post Cat sensor - then its likely to be the sensor still

If the fault stay at Pre-cat, then you are certainly looking at a wiring / ECU issue

Ziggy