I need some help with an O2 sensor issue.

Replaced Bank 1 upstream sensor because I was getting code P0130.

During this process 2 of the wires broke off the connection. There just was not enough wire material to work with in the space allowed.

I created a new wiring loom with a connector sourced from a salvage yard.

I have used 18 gauge wire.

Pin #1 goes to connector C0635 at the ECU to #9 cut and spliced in
Pin #2 goes to connector C6035 at the ECU to #15 cut and spliced in
Pin #4 goes to connector C0635 at the ECU to #19 cut and spliced in

Pin #3 goes to connector C0203 and attaches onto wire #14

Code P0134 per Rave is LH Bank open circuit.

I have switched the left and right bank O2 sensors after installing the new wiring loom with the same results so I know it is not the O2 sensor.

I did check continuity on all the wires on the loom before I installed them.

Has anyone had something similar?

2003 North American Discovery 2

Thanks,

 

I suppose the next step is checking continuity between C0203-14 and C0573-3. As well as C0203-14 and C0378-7 (aka C0392-7).

 

I realized today I am fortunate to be able to to check continuity with my wiring loom and the spices I have made.

So with the new wiring loom I have continuity with all 4 wires from the connector that goes to the sensor and the connector that plugs into the ECU.

I have also checked for voltage with the key in the run position.
#3 is getting strong voltage. (because of this I believe the continuity between C0203 and the fuse box is good)
#1 is earth
#2 is getting the 1/2 volt from the ECU
#4 is getting the 1/2 volt from the ECU

There is another thread that speaks about P0134 and the purge valve. That will be my next step before replacing the spark plugs and wires.

Again, I have swapped the O2 sensors so they are not this issue

 

P0134 shouldnt be set by a purge or evap fault, its a dead ringer for a bad O2, related wiring issue. Evap wont be tied to that at all

From Alldata:

DTC P0134
Lambda sensor upstream catalyst bank 1 Drive cycle C:Signal missing.

Possible causes by suggested order of priority:
^ Oxygen sensor heater not functioning correctly.
^ Open circuit C635/15 (O) to C644/2 (O).
^ Open circuit C635/9 (RB) to C644/1 (RB).
^ Connector(s) C644,ECM C635 (B).
^ Oxygen sensor damaged or surface contaminated.

Oxygen Sensor Heater Not Functioning Correctly.
CHECK THE FOLLOWING:
^ Oxygen sensor heater fault flags are set.
INFORMATION
^ If the oxygen sensor is not at the correct operating temperature the sensor may appear faulty to the motronic diagnostics system. This fault should be diagnosed by exploring the oxygen sensor heater faults which will be set if this fault is present.

Open Circuit C635/15 (O) to C644/2 (O).
OPEN_CIRCUIT
^ Check resistance > 1M Ohm

Open Circuit C635/9 (RB) to C644/1 (RB).
OPEN_CIRCUIT
^ Check resistance > 1M Ohm

Connector(s) C644,ECM C635 (B).
CONNECTOR
^ Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.

Oxygen Sensor Damaged Or Surface Contaminated.
CHECK THE FOLLOWING:
^ Remove the oxygen sensor and examine the side internal to the exhaust system and the side outside the exhaust system. Both sides of the sensor should be free from contamination. Gas must be able to be absorbed by both sides of the sensor.
^ Also check the sensor for any mechanical damage or cracks.
INFORMATION
^ If the oxygen sensor shows signs of damage or contamination that cannot be cleaned it should be renewed.

 

Llamasayswhat,

Thank you for the help.

I will check the resistance. I did use 18 gauge wire, maybe that is the issue.

I had checked continuity between C6444 and C635 but had not checked resistance.

I'm just now learning via Youtube how to check resistance on some sample wires with my multi-meter.

I have the setting at 200 Ohms. Is this the correct setting?

I am getting way over 1 for the gauge wire the Discovery 2 originally uses. Not sure what gauge it is but is is definitely small than 18 gauge.

The 18gauge sample wire I used is getting resistance lower than 1.

I will check the loom I made. Hope this is the issue and I'll just have to find the gauge wire the Discovery 2 originally had. I had chosen 18 gauge because that's all the auto repair store had.

Thanks again,

 

Here is the update on my 2003 D2 still getting P0134 code. This code is the lack of voltage reading from the left bank upstream O2 sensor.

Backstory, wires going into the connection broke entirely off during a change of the O2 sensor since it was giving me P0130 code.

Here is what I have done.

Replaced the entire engine wiring harness I got from Will the Roverguy

Replaced the O2 sensor, have a Walker, Bosch and switched the one from the right side with no success with any.

After the wiring harness I switched 2 wires going into C0635 going into the ECU. I switched #15 and #16. These are the 2 wires that run from reach front O2 sensor and give the ECU voltage reading. When I did this the left bank showed voltage and the right bank was stuck in the open loop mode showing 450mV. Because of this I believe the ECU is good.

Any ideas?

 

So you are saying when you switched, the wires, the voltage followed the wires ie voltage on the right consistently, no voltage on the left. You previously switched the sensors left to right, and the voltage stayed with the wires. All there is to the circuit is the sensors and the wires. If the ECU can see the switch, it has to be one of those two items, you just need to determine which one.

 

Here is the latest with my O2 sensor issue for Bank 1 upstream.

I am getting voltage readings but they are not the same as Bank 2 upstream.

Bank 2 up is a variable voltage reading that swings from .03 and goes to .850 or so. I believe this is correct.

Bank 1 upstream is giving a voltage reading but hovers around plus or minus .25 (so it would be around .540 to .565)

I began driving it yesterday and each test ride got better. The first test ride the readings went from .450 and moved to 1.125 within five minutes and then the check engine light came on.

The second test drive it took longer to get to 1.125 and the check engine light came on. By the 6th test drive it would not go above the .800's and would be fine although it would idle very rough.

This morning the first test drive threw a code P0130. I decided to switch from the Walker O2 sensor to the Bosch. The first test drive with the Bosch went fine and the voltage stayed in the .600's. The second test drive threw the code of P0134.

I believe the voltage reading not showing big swings and staying close together is the clue to solving this issue. The ODB2 reader has a graph with the voltage reading. It's almost flat with bank 1 but bank 1 it is an up and down line.

When I did swap the wires for the signal wire going into the ECU bank 1 showed the same graph with the voltage reading up and down and the voltage with big spread of low to high.

Any help is appreciated.

Thanks,

 

Try swapping the bank 1 upstream with the bank 2 upstream. If voltage changes its bad sensor, if it looks same wiring is wrong.

 

Post a screenshot of the graphs.