O2 sensor or wiring?

[q76767]

Can you copy and paste that code please ?

I would have expected 2 codes at least ?

This is with o2 sensor unplugged.

000054 - Oxygen (Lambda) Sensor B1 S2: Heating Circuit
               P0036 - 000 - Malfunction / Open Circuit - MIL ON
             Freeze Frame:
                    Fault Status: 11100000
                    Fault Priority: 0
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 244868 km
                    Time Indication: 0
                    Date: 2063.14.31
                    Time: 00:23:12

             Freeze Frame:
                    RPM: 844 /min
                    Load: 24.7 %
                    Speed: 0.0 km/h
                    Temperature: 68.0°C
                    Temperature: 51.0°C
                    Absolute Pres.: 1000.0 mbar
                    Voltage: 13.970 V


Readiness: 0010 0101

 

[Dr Sheldon]

This is with o2 sensor unplugged.

000054 - Oxygen (Lambda) Sensor B1 S2: Heating Circuit
P0036 - 000 - Malfunction / Open Circuit - MIL ON

In that case we have evidence that the 2 Heater Wires are intact !

But no code for the other half of that sensor


What about this code
004372 - Oxygen (Lambda) Sensor; B1 S2
P1114 - 000 - Internal Resistance too High

Does it stay away or return ?

https://imgur.com/a/7i8k7eM

Your area of interest are the 2 wires Red and Brown Pins 84 & 72 at the ECU.

These carry very little current so no need to go Mad putting a big load on them - If each can carry 1 amp then that will do.

The other thing to try as to join those 2 wires together with a paper clip or similar and see if we can raise a Code for Short Circuit /Low Resistance

 

[q76767]

In that case we have evidence that the 2 Heater Wires are intact !

But no code for the other half of that sensor


What about this code
004372 - Oxygen (Lambda) Sensor; B1 S2
P1114 - 000 - Internal Resistance too High

Does it stay away or return ?

https://imgur.com/a/7i8k7eM

Your area of interest are the 2 wires Red and Brown Pins 84 & 72 at the ECU.

These carry very little current so no need to go Mad putting a big load on them - If each can carry 1 amp then that will do.

The other thing to try as to join those 2 wires together with a paper clip or similar and see if we can raise a Code for Short Circuit /Low Resistance

with the red and brown wire joined no different codes pop up just the same P0036 open circuit for heaters. So that would mean one of my wires red or brown has a break somewhere between the plug and ecu? I can probe them at connector and ecu see which does not have continuity and whichever one does not splice in a new wire from ecu harness to o2 sensor plug?

this one does not return
004372 - Oxygen (Lambda) Sensor; B1 S2
P1114 - 000 - Internal Resistance too High

https://imgur.com/a/2dqxRYn

 

[Dr Sheldon]

I can probe them at connector and ecu see which does not have continuity and whichever one does not splice in a new wire from ecu harness to o2 sensor plug?

Yes !

Or find the break

 

[q76767]

Yes !

Or find the break

Pin 3 on car connector to pin 72 on ecu harness goes straight to 000 on continuity and pin 4 on car connector to pin 84 on ecu harness goes right to 000 on continuity. So it seems like the wiring is good?

 

[q76767]

This is where I had multi meter set

https://imgur.com/a/jgEqxaX

 

[davisev5225]

Pin 3 on car connector to pin 72 on ecu harness goes straight to 000 on continuity and pin 4 on car connector to pin 84 on ecu harness goes right to 000 on continuity. So it seems like the wiring is good?

I'd re-test using the "200 ohm" setting instead of 2000, and wiggle the harness around at various points while testing and watching your meter to make sure you don't have an intermittent issue such as a break that's still touching. Might also be worth removing the ECU harness and cleaning the contacts - I've had more than one instance personally of minor amounts of oxidization in the ECU harness connection causing "phantom" problems, despite it visually looking perfect. You might be running into the same issue here. O2 sensors run a signal voltage of less than 1V, so any tiny amount of resistance in the line can cause it to malfunction.

 

[q76767]

I'd re-test using the "200 ohm" setting instead of 2000, and wiggle the harness around at various points while testing and watching your meter to make sure you don't have an intermittent issue such as a break that's still touching. Might also be worth removing the ECU harness and cleaning the contacts - I've had more than one instance personally of minor amounts of oxidization in the ECU harness connection causing "phantom" problems, despite it visually looking perfect. You might be running into the same issue here. O2 sensors run a signal voltage of less than 1V, so any tiny amount of resistance in the line can cause it to malfunction.

Set on 200 ohm pin 3 on car to 72 on ecu gets 00.3 and pin 4 on car to ecu pin 84 gets 00.3-00.4. Tried wiggling harness no change in numbers

 

[stefdds]

Building on what has been mentioned above ; I think I would also disconnect the ECU completely from the harness and using the two pin locations mentioned above you can now test only the wiring (at each end) and Load them (safely, ie no ecu connected). You have access to both ends of those wires so using what ever method you can rig up put 12v thorough each of those wires , one at a time.
Place the DVM on each wire while you supply battery voltage to each wire. Measure battery voltage first so you have a number, then connect to each wire separately.. does that voltage number drop substantially ?

 

[q76767]

Building on what has been mentioned above ; I think I would also disconnect the ECU completely from the harness and using the two pin locations mentioned above you can now test only the wiring (at each end) and Load them (safely, ie no ecu connected). You have access to both ends of those wires so using what ever method you can rig up put 12v thorough each of those wires , one at a time.
Place the DVM on each wire while you supply battery voltage to each wire. Measure battery voltage first so you have a number, then connect to each wire separately.. does that voltage number drop substantially ?

During the test above I had ecu disconnected completely. So basically put 12 volts to one end of wire and measure what it is by time it reaches other end seeing if it drops running through the wire?

 

[davisev5225]

Set on 200 ohm pin 3 on car to 72 on ecu gets 00.3 and pin 4 on car to ecu pin 84 gets 00.3-00.4. Tried wiggling harness no change in numbers

Those are reasonable numbers for an unloaded wire. Time to load test per @stefdds' recommendation. If that also passes with no significant voltage drop (a couple hundredths of a volt drop is fine, but if you lose more than a tenth of a volt, then you've got issues), then it's time to load the parts cannon again. Advance Auto is probably fine, but I'd still recommend FCP Euro or Europa Parts.

This should be the correct part for your downstream sensor:

Oxygen Sensor (16136, Latest Revision)

Brand new, Genuine Bosch OEM oxygen sensor. Exposure to carbon, soot, harmful gases, antifreeze, chemicals, and thermal and physical shock will shorten the life of an oxygen sensor. A worn sensor could result in reduced gas mileage, poor engine performance, and/or emissions test failure. That's...

www.europaparts.com

 

[q76767]

Those are reasonable numbers for an unloaded wire. Time to load test per @stefdds' recommendation. If that also passes with no significant voltage drop (a couple hundredths of a volt drop is fine, but if you lose more than a tenth of a volt, then you've got issues), then it's time to load the parts cannon again. Advance Auto is probably fine, but I'd still recommend FCP Euro or Europa Parts.

This should be the correct part for your downstream sensor:

Oxygen Sensor (16136, Latest Revision)

Brand new, Genuine Bosch OEM oxygen sensor. Exposure to carbon, soot, harmful gases, antifreeze, chemicals, and thermal and physical shock will shorten the life of an oxygen sensor. A worn sensor could result in reduced gas mileage, poor engine performance, and/or emissions test failure. That's...

www.europaparts.com

No Voltage drops at all when putting power to ecu side harness and then checking down under car at o2 sensor harness plug. So has to be either a bad ecu or a faulty o2 sensor?

 

[davisev5225]

Use some contact cleaner and a nylon brush to carefully clean the plug and socket at the ECU end of the harness, then reassemble. I'd say it's safe to try the "parts cannon" again and try one more O2 sensor, it is significantly cheaper than trying to replace the ECU.

Oxygen Sensor (16136, Latest Revision)

Brand new, Genuine Bosch OEM oxygen sensor. Exposure to carbon, soot, harmful gases, antifreeze, chemicals, and thermal and physical shock will shorten the life of an oxygen sensor. A worn sensor could result in reduced gas mileage, poor engine performance, and/or emissions test failure. That's...

www.europaparts.com

 

[Dr Sheldon]

Let us play this the easy way.

Those wires do not need to be load tested - They need to carry very little current, and very little Voltage !!

And then putting 12v into one end and measuring 12v at the other is NOT Load testing Neither is it VOLT DROP testing.

Those testing tips above are not correct and prove less than nothing !! - You have gained a false Positive there - that could have made the job harder for you.



Furthermore the fact that the ECU can identify the descriptive faults below would be very "sexy" with a broken wire !!

000320 - Oxygen (Lambda) Sensor B1 S2
P0140 - 000 - No Activity

004372 - Oxygen (Lambda) Sensor; B1 S2
P1114 - 000 - Internal Resistance too High

I would fire 0.5 volts up the sensor wire into the ECU and compare what I have in the MVB for it.

You can buy a O2 Sensor Simulator - I use one for this type of failure diagnosis !! That way you can confirm or deny ECU health

 

[EuroX]

Check to see if wires are shorted to each other for o2 sensor either isolate the o2 sensor and check or check at ecm connector and trace backwards.

 

[q76767]

Check to see if wires are shorted to each other for o2 sensor either isolate the o2 sensor and check or check at ecm connector and trace backwards.

I don't belive they are shorted to each other as when I was shooting power down one of them the other didn't have power. I would think if shorted together they'd both get power.

 

[q76767]

Let us play this the easy way.

Those wires do not need to be load tested - They need to carry very little current, and very little Voltage !!

And then putting 12v into one end and measuring 12v at the other is NOT Load testing Neither is it VOLT DROP testing.

Those testing tips above are not correct and prove less than nothing !! - You have gained a false Positive there - that could have made the job harder for you.



Furthermore the fact that the ECU can identify the descriptive faults below would be very "sexy" with a broken wire !!



I would fire 0.5 volts up the sensor wire into the ECU and compare what I have in the MVB for it.

You can buy a O2 Sensor Simulator - I use one for this type of failure diagnosis !! That way you can confirm or deny ECU health

I can order a simulator probably good to have. How would I send 0.5 volts through the sensor wire? Sorry what does MVB stand for?

 

[q76767]

I put another Bosch in I picked up locally, says Bosch on it. I let it idle and turned on and off a handful of times over past couple hours and the code for no activity intermittent came back!

 

[davisev5225]

I put another Bosch in I picked up locally, says Bosch on it. I let it idle and turned on and off a handful of times over past couple hours and the code for no activity intermittent came back!

Just checking, did the code come back, or did you mean to say it did not come back?

 

[q76767]

Just checking, did the code come back, or did you mean to say it did not come back?

It did come back still has an issue