P0140 - O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 2) : Advice please :-)

[Envy]

Hi All

My mate has a signum 2004 elegance 2.0t

He has had an off and on problem with the emissions light coming on. I cleared this a few times with the "cough cough" pretend Tech2 device but it would come back in a matter of seconds.

He took it to a garage and they found that the lambda sensor cables "I beleive the one behind the cat" had been cut or just had come apart in the middle.

They joined the wires somehow and wrapped it up with insulating tape.

I can clear the fault code now and it runs for about a day but then the fault comes back.

Im thinking dodgy repair (it does not look good) and some if not a few cables are coming apart slightly when flexing when driving.

Im going to get under it tomorrow and remove it and try soldering the wires then heat shrinking it and making sure its water tight etc.

If that does not fix it then its a new sensor but the price of these are rather high.

I was thinking of buying a non GM part and exchanging the end connector for the one he has at the moment.

What I'm asking is it worth it or am I asking for trouble going down this route.

Are the non GM sensors any good?

Will a wire repair be up to the job?

Will exchanging the existing connector onto a non GM part be any good?

Should we just bite the bullet and get a new proper one. If so does anyone have any good to links for this part at a good price.

Many thanks

Chris

[Critch]

Test O2 sensor with a multimeter.
I'd be suspecting its melted through from exhaust an shorting out signal wire

Also See what reading your getting at ECM

[Critch]

Taken from this page for you might help
http://www.obd-codes.com/p0140

This is a fairly specific problem and shouldn't be too difficult to diagnose.
First, start engine and warm up. Using a scan tool, watch the Bank 1, sensor 2, o2 sensor voltage. Normally the voltage should switch slowly above and below .45 volts. If it does, the problem is likely intermittent. You'll have to wait for the problem to surface before you can accurately diagnose.
However, if it doesn't switch, or is stuck then perform the following: 2. Shut off vehicle. Visually check the Bank1,2 harness connector for melting or chafing of the harness or the connector. Repair or replace as needed 3. Turn ignition on, but engine off. Disconnect the O2 sensor connector and check for 12Volts at the Heater Circuit supply and for proper ground on the heater circuit ground circuit. a. If 12V heater supply is missing, check the proper fuses for an open in the circuit. If heater circuit fuse is blown, then suspect a bad heater in the o2 sensor causing a blown heater circuit fuse. Replace sensor and fuse and recheck. b. If ground is missing, trace the circuit and clean or repair ground circuit. 4. Next, with connector still unplugged, check for 5 Volts on the reference circuit. If this is missing, check for 5 Volts at the PCM connector. If 5 Volts is present at the PCM connector but not at the o2 sensor harness connector, then there is an open or short in the reference wire supply between the PCM and the o2 sensor connector. However, if there is no 5 Volts present at the PCM connector, the PCM is likely at fault due to internal short. Replace PCM. ** (NOTE: on Chrysler models, a common problem is the 5Volt reference circuit can be shorted out by any sensor on the car that uses a 5 Volt reference. Simply unplug each sensor one at a time until the 5 Volts reappears. The last sensor you unplugged is the shorted sensor. Replacing it should fix the 5 Volt reference short.) 5. If all the voltages and grounds are present, then replace the Bank 1,2 O2 sensor and re-test.

[Envy]

Thanks very much Critch.

That gives me a lot to go on.

Will see what comes up tomorrow and report back here.

Thanks again matey, much appreciated