I need to pass smog in CA, the car currently sniffed clean but failed due to the check engine light. I have since replaced all four oxygen sensors with Bosch OE replacements.

I am getting the following codes:

P0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1)
P0152 O2 Sensor Circuit High Voltage (Bank 2 Sensor 1)

My question is if there is a diagram that shows where the plugs for the sensors connect in order to cross check my work in that regard.

Also where is Bank 1 vs Bank 2 in relation to the pre and post cat sensors?

 

BUMP

 

UPDATE:

I had my front/up stream sensors wires crossed. Since fixing my mileage (computer stated average) has gone over 30 MPG. How can this be? The car admittedly runs amazing now but that seems like excessively good mileage.

I am still getting P0152 & P01323 codes however. Someone please chime in with any input

 

I'm having the same issue; What does HIGH VOLTAGE mean and how can it be fixed?

I can't get this CEL to go away and it's preventing me from passing California smog.

 

I would infer you are referring to a OBD code for one of your Lambda sensors. If that is right, then you have a bad sensor, bad wiring, or a bad ECU, in that order.

If you would like better information, how about a better post of exactly what you have, what car, and what you want to know.

 

So, how did you decide your sensors were crossed? The circuits can be connected either way depending on the "orientation" completed with the dealer software!

 

SD96XJ6L,

To clarify one point in Ross' excellent suggestions, please post the exact and complete OBD fault code(s) you have scanned in your '97 XJ6L. The whole point of the codes is to reduce the amount of guesswork in the diagnosis.

Cheers,

Don

 

1997 XJ6 4.0L 118K miles

CODES ARE P0152 & P0132

The car has 4 new Bosch 02 sensors, new Bosch fuel pressure regulator, recently flushed injectors with new seals & baskets, brand new coil packs, brand new plugs and my computer is telling me I'm getting close to 30 MPG right now and the car is running like a Jaguar that has been caged for years, meaning it's running amazingly well I just can't figure out why I have these codes and need to pass smog here in CA

 

I looked up the wiring diagram. Not to self: remove one at a time.

 

The wiring diagram will not tell you which orientation has been taught to the ecu.

 

P0132 applies to the circuit for the upstream O2 sensor for bank 1 or A (cylinders 1, 2 & 3). P0152 applies to the upstream O2 sensor for bank 2 or B (cylinders 4, 5, 6). For both codes, the possible causes are the same:

HO2S disconnected
Cylinders 1, 2, 3 (A bank), upstream (1) idle > 25 seconds HO2S signal ground wire open circuit
HO2S sense wire open circuit or short circuit to B+ voltage
HO2S failure
HO2S heater malfunction (tip temperature too cold)

I am attaching the '96-'97 X300 DTC summaries manual for reference.

Given your symptoms and the fact that you have four new Bosch O2 sensors, a few questions and thoughts come to mind:

1. Did you purchase O2 sensors with the electrical connectors installed at the factory? The internet is full of reports of problems with the "universal" type sensors that require the user to install the connector.

2. Can you confirm that the Bosch O2 sensors are of the correct type, which I believe should be Titania and not Zirconia. Ross can confirm if I've got this wrong.

3. Have you confirmed that the electrical connectors for both upstream sensors are clean, free of corrosion, and connected firmly?

4. These are 4-wire sensors, so I don't believe they rely on a ground path through the exhaust, so corrosion in the exhaust port threads should not be your problem. The shields for all four sensor signal wires are grounded at the RH bulkhead ground stud. Whether cleaning the ground stud and wire ring terminals might help I don't know, but it would be worth a try.

5. The sensors connect directly to the ECM. If all else fails, it might be worth checking for corrosion or water ingress at the ECM connector.

You can check for the proper supply voltage for the sensor heaters at their electrical connectors (across the Purple/Brown and White/Green wires of the harness connectors for the upstream sensors). I believe the voltage should be 12V but it's possible it may be only 5V.

At the link below you can download the '97 X300 Electrical Guide so you can see the schematics for the O2 sensors on the pages for the Engine Management System.

http://www.jagrepair.com/images/Auto.../jagxj1997.pdf

Cheers,

Don

 

I'm not Ross but I can confirm this.
This is from the service manual:
"The sensors are of the Titanium Dioxide (TiO2) type, which have a tip, composed of an alumina substrate with a thick film titanium dioxide element. The TiO2 sensor does not require reference air to detect the oxygen content of the exhaust, so flooding or contamination of the sensor exterior will not affect sensor performance. The resistance of the sensor element varies greatly with the partial pressure of oxygen in the exhaust gas. This change in resistance is converted to a change in voltage output to the ECM via a constant voltage source and reference resistance. Whenever the air / fuel ratio passes lambda-1 (stoichiometric mixture), the sensor delivers a voltage swing, indicating whether the mixture is richer or leaner than lambda-1."

 

Thank you Don & Scarecrow,

Don, answers below in BOLD

1. Did you purchase O2 sensors with the electrical connectors installed at the factory? The internet is full of reports of problems with the "universal" type sensors that require the user to install the connector. Yes

2. Can you confirm that the Bosch O2 sensors are of the correct type, which I believe should be Titania and not Zirconia. Ross can confirm if I've got this wrong. Yes

3. Have you confirmed that the electrical connectors for both upstream sensors are clean, free of corrosion, and connected firmly? Yes

5. The sensors connect directly to the ECM. If all else fails, it might be worth checking for corrosion or water ingress at the ECM connector. Where is the ECM? I will check.

 

It is confusing when you start two threads about the same problem.

The high voltage indication indicates that the sensors are not pulling the sense circuit towards ground. That could be because the sense lead is not connecting due to the causes mentioned already OR the sensor is not functioning due to the heater circuit not working. I do not have the schematic in front of me, but if you read the voltages to ground on the four wires, for each of the two upstream sensors, I bet we can figure it out.


BTW, even though the codes do not indicate this problem directly, pay heed and understand what I told you in the othe rpost about re-orientation of the ECU.

 

How do I measure the voltages exactly? I have a digital multimeter. Now what? haha

thanks again

 

Probe the back of each conductor in the connector with the red lead while the black lead is connected to a good ground point.

 

I stupidly mixed up the downstream O2 wires, and the car had a weird idle misfire and would throw a random misfire code. I used my OBD2 scanner to see the live data and saw the fuel trims were reading 50+ for bank 1 and -50 for bank 2 at idle. Oops, problem easily solved by swapping connectors back.

The O2 sensor banks refers to either cylinders 123 or 456. Sensor 1 is your upstream O2 (before the cats). Sensor 2 is downstream (after the cats). So both your upstream O2 sensors may be toast. I believe the downstream sensors are the ones that the ECU uses for the main fuel data.

 

I didn't realize you had two threads and replied to the other one.

 

SD96XJ6L,

I have merged all posts on this topic to this thread to reduce confusion and duplicate replies.

Cheers,

Don

 

I tested the two front oxygen sensors. They both ready roughly 6 volts.