bravo dtcs

[tommo]

01 bravo (80 16v cf3) has the following ailments po141/p1141/u1600.
Could someone diagnose the problem and advise on a remedy.
Would a bad air filter be the culprit?

regards

Tommo

[Juggers2k]

P0141 = O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P1141 = O2 Sensor Heater Control - Heater Resistance Too High (Bank 1 Sensor 2)
U1600 = Immobiliser System - Malfunction

So the first 2 look like a heater fault (or wiring fault) on your rear oxygen sensor.
You can test that if you have a multimeter - the sensor will have 3 or 4 wires, 2 of which will be the same colour, the other 1 or 2 wires will be different colours. Measure the resistance between the 2 wires of the same colour - if the heater coil is ok the resistance should be around 4-6 Ohms (on some vehicles it can be as high as 15 Ohms).
If the resistance is very high or very low, then the heater coil has failed, so you need to replace the sensor.
If the resistance is ok, check the wiring to the sensor.

As for the U1600, that relates to an incorrectly programmed key, or a failure of the key transponder or the reader on the car. If the car starts ok you can probably ignore that one.

[tommo]

THANKS for the assistance! Tried to "zap" the problem in the bud with my extraterrestial software "ray gun.
Dem aliens disappeared for breakfast but arrived back for dinner!!
Will follow your instructions and keep you posted.

regards

Tommo

[tommo]

Used my multimeter on the 2/ o2 sensors. The first sensor read (10 ohms) on the heater circuit/the voltage supply
with ignition in the "on" position was ("8.75 volts")
The 2nd downstream sensor read (0 ohms) on the heater circuit/the voltage supply was (.47 volts)
What needs to be done next ?

[Juggers2k]

Used my multimeter on the 2/ o2 sensors. The first sensor read (10 ohms) on the heater circuit/the voltage supply
with ignition in the "on" position was ("8.75 volts")
The 2nd downstream sensor read (0 ohms) on the heater circuit/the voltage supply was (.47 volts)
What needs to be done next ?

The fault codes pointed to sensor 2 (downstream sensor), so that makes sense.
If you're getting 0 Ohms resistance, that would suggest the heater coil has failed and is now shorting, so the electricity supplied to it can bypass the coil, not heating it up.
So pretty much a dead rear oxygen sensor - time to replace it.

Aftermarket replacement sensors are relatively inexpensive for most Fiat models - e.g.:
http://www.gendan.co.uk/oxygen_lambda_s ... Bravo.html

[tommo]

Will replace 02 sensor and report of the findings when I have
it installed.

regards

Tommo

[tommo]

Reporting back! have replaced 2 sensors front and back Tested the supply coming to the sensor heaters and

found a live on both sockets but could not find an earth . I did this test using a car bulb, with reference to both poles of the battery.

The ignition was fully on but the engine was not running.Where does the earth come from? or are they grounded by

the ECU?

[Juggers2k]

Reporting back! have replaced 2 sensors front and back Tested the supply coming to the sensor heaters and

found a live on both sockets but could not find an earth . I did this test using a car bulb, with reference to both poles of the battery.

The ignition was fully on but the engine was not running.Where does the earth come from? or are they grounded by

the ECU?

It's possible the ground is broken unless the engine is running - otherwise the coil would be draining the battery while the ingition is turned on.
Try starting the engine and measure again.