P1646 Code
#1
09-08-2015, 02:20 AM
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P1646 Code
Hi Guys .Im a newby here .Hopefully you can help me.I have just acquired a 2002 X-Type Jag Its a lovely car and has only done 50.000 miles.It has been laid up for 6 months .I am getting a code P1646 on my friends diagnosis computer .Its telling me its a heated oxygen sensor control module Bank 1 open or shorted.It drives well but this code thing is worrying and I am not good with car mechanics.Any Ideas .How much is a replacement .Im in the UK.Thanks in advance Steve
#2
09-08-2015, 04:37 PM
Fill in the exact details here for your car or ring them, you need the upstream sensor, which is usually more than the downstream ones
Lambda Sensor | Quality Lambda Sensors For Cars Of All Makes & Models
Denso or Bosch, though not the Bosch one listed here
Avoid universal ones, it is a part which goes rarely so fit the best possible
You could also ask here if someone can recommend a fitter in your location
X-Type
Lambda Sensor | Quality Lambda Sensors For Cars Of All Makes & Models
Denso or Bosch, though not the Bosch one listed here
Avoid universal ones, it is a part which goes rarely so fit the best possible
You could also ask here if someone can recommend a fitter in your location
X-Type
#3
09-08-2015, 07:18 PM
stevie: Pictures with locations of all 4 oxygen sensors are in this thread: https://www.jaguarforums.com/forum/x...-where-129374/
The error code P1646 is telling you to replace the upstream oxygen sensor on Bank 1, the firewall side. It's easy to see, but not so easy to reach with a socket and breaker bar.
To locate this sensor, open the hood and stand by the left front wheel - the UK passenger side. Look for two electrical connectors mounted on the firewall next to the power brake booster, towards the center of the car. One is light grey, the other black. These are for the upstream (grey) and downstream (black) oxygen sensors. Trace the wires from the grey electrical connector down between the engine and the firewall to the upstream oxygen sensor. This sensor needs to be replaced because it has an electric heating element (like a toaster) that goes back with age.
The Bosch replacement part # is 15627:
The Denso replacement part # is 234-9029: _
To remove and install the sensor, you'll need a special 7/8 inch socket, like a spark plug socket, but with a slot cut for the sensor's wires: _
This post also has pictures of the special socket: https://www.jaguarforums.com/forum/x...0/#post1059714
In the US, we often borrow special tools like this from the local auto parts store. Hopefully you can borrow one as well.
As I mentioned, this sensor is easy to see, but not so easy to reach with a socket and breaker bar. This post describes one way to reach it: https://www.jaguarforums.com/forum/x...1/#post1247370
If you have any questions, let me know and I'll try to walk you thru it. It's not that difficult, but does take some patience and persistence
Good luck.
The error code P1646 is telling you to replace the upstream oxygen sensor on Bank 1, the firewall side. It's easy to see, but not so easy to reach with a socket and breaker bar.
To locate this sensor, open the hood and stand by the left front wheel - the UK passenger side. Look for two electrical connectors mounted on the firewall next to the power brake booster, towards the center of the car. One is light grey, the other black. These are for the upstream (grey) and downstream (black) oxygen sensors. Trace the wires from the grey electrical connector down between the engine and the firewall to the upstream oxygen sensor. This sensor needs to be replaced because it has an electric heating element (like a toaster) that goes back with age.
The Bosch replacement part # is 15627:
The Denso replacement part # is 234-9029: _
To remove and install the sensor, you'll need a special 7/8 inch socket, like a spark plug socket, but with a slot cut for the sensor's wires: _
This post also has pictures of the special socket: https://www.jaguarforums.com/forum/x...0/#post1059714
In the US, we often borrow special tools like this from the local auto parts store. Hopefully you can borrow one as well.
As I mentioned, this sensor is easy to see, but not so easy to reach with a socket and breaker bar. This post describes one way to reach it: https://www.jaguarforums.com/forum/x...1/#post1247370
If you have any questions, let me know and I'll try to walk you thru it. It's not that difficult, but does take some patience and persistence
Good luck.
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viper1996 (09-16-2021)
#4
09-09-2015, 07:06 AM
Join Date: Sep 2015
Location: Wirral
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#5
09-09-2015, 08:09 AM
Stevie: This oxygen sensor may be easier to replace on your UK car than our US cars. The brake booster is on the driver's side: the left side of our US cars, and the right side of your UK car. So you have more open space on the left side of your engine compartment to remove & replace the upstream Bank 1 oxygen sensor.
#6
02-16-2017, 08:02 AM
Hi Guys .Im a newby here .Hopefully you can help me.I have just acquired a 2002 X-Type Jag Its a lovely car and has only done 50.000 miles.It has been laid up for 6 months .I am getting a code P1646 on my friends diagnosis computer .Its telling me its a heated oxygen sensor control module Bank 1 open or shorted.It drives well but this code thing is worrying and I am not good with car mechanics.Any Ideas .How much is a replacement .Im in the UK.Thanks in advance Steve
P1646 indicates some problem leading to bad readings from the bank 1 upstream (upper, before the cat) oxygen sensor. It could be a problem with the sensor, the wiring, or even the fuse which supplies current to the heater in it. Are you getting any other codes as well ?
Bank 1, on the sideways-mounted V6 engine, is up against the bulkhead. You will see the two electrical connectors for the bank 1 sensors pretty much amidships on the bulkhead just slightly to the left (looking forwards) towards the brake servo.
Do avoid cheap replacements at around £30 or so. Good ones, up to Jaguar standards, will cost you between £70 and £90 depending on supplier. I learned this the hard way !
The original Denso sensors use a pale grey plug for the upstream sensor and a black plug for the downstream sensor. Some of the cheap replacements use a darker grey plug and can be mis-identified by the supplier. The original plugs are subtly different, and shouldn't fit wrongly, but they can be forced (but don't !).
Fitting will involved removing the inlet manifold as it kind of 'folds-over' the bank one cylinder head. While that is off, you might as well get the spark plugs changed (use very good ones) as well and also the gaskets/o-ring seals on the manifold. You will need the correct tool to remove and re-fit the oxygen sensor, but it is not really expensive and should serve you all your motoring life. My set of 3 only cost me a tenner off e-bay !
Good luck with this - do take the time to check the connectors & fuses before you start dismantling things !
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bbzee (05-23-2017)
#7
07-10-2018, 01:05 AM
I received a Denso downstream oxygen sensor from Amazon with only 19, not 21.3 inch!
[QUOTE=dwclapp;1304406]stevie: Pictures with locations of all 4 oxygen sensors are in this thread: https://www.jaguarforums.com/forum/x...-where-129374/
The error code P1646 is telling you to replace the upstream oxygen sensor on Bank 1, the firewall side. It's easy to see, but not so easy to reach with a socket and breaker bar.
To locate this sensor, open the hood and stand by the left front wheel - the UK passenger side. Look for two electrical connectors mounted on the firewall next to the power brake booster, towards the center of the car. One is light grey, the other black. These are for the upstream (grey) and downstream (black) oxygen sensors. Trace the wires from the grey electrical connector down between the engine and the firewall to the upstream oxygen sensor. This sensor needs to be replaced because it has an electric heating element (like a toaster) that goes back with age.
The Bosch replacement part # is 15627:
The Denso replacement part # is 234-9029: _
To remove and install the sensor, you'll need a special 7/8 inch socket, like a spark plug socket, but with a slot cut for the sensor's wires: _
This post also has pictures of the special socket: https://www.jaguarforums.com/forum/x...0/#post1059714
Dyson, the harness of the Denso downstream oxygen sensor just received from Amazon measures only 19 inch, what should I do? (I am still in NY)
The error code P1646 is telling you to replace the upstream oxygen sensor on Bank 1, the firewall side. It's easy to see, but not so easy to reach with a socket and breaker bar.
To locate this sensor, open the hood and stand by the left front wheel - the UK passenger side. Look for two electrical connectors mounted on the firewall next to the power brake booster, towards the center of the car. One is light grey, the other black. These are for the upstream (grey) and downstream (black) oxygen sensors. Trace the wires from the grey electrical connector down between the engine and the firewall to the upstream oxygen sensor. This sensor needs to be replaced because it has an electric heating element (like a toaster) that goes back with age.
The Bosch replacement part # is 15627:
The Denso replacement part # is 234-9029: _
To remove and install the sensor, you'll need a special 7/8 inch socket, like a spark plug socket, but with a slot cut for the sensor's wires: _
This post also has pictures of the special socket: https://www.jaguarforums.com/forum/x...0/#post1059714
Dyson, the harness of the Denso downstream oxygen sensor just received from Amazon measures only 19 inch, what should I do? (I am still in NY)
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#8
07-10-2018, 04:56 AM
When quoting only part of a post, take care not to remove the End QUOTE code.
Graham
Last edited by GGG; 07-10-2018 at 04:58 AM.
#9
11-21-2019, 07:51 PM
Hi Stevie,
P1646 indicates some problem leading to bad readings from the bank 1 upstream (upper, before the cat) oxygen sensor. It could be a problem with the sensor, the wiring, or even the fuse which supplies current to the heater in it. Are you getting any other codes as well ?
Bank 1, on the sideways-mounted V6 engine, is up against the bulkhead. You will see the two electrical connectors for the bank 1 sensors pretty much amidships on the bulkhead just slightly to the left (looking forwards) towards the brake servo.
Do avoid cheap replacements at around £30 or so. Good ones, up to Jaguar standards, will cost you between £70 and £90 depending on supplier. I learned this the hard way !
The original Denso sensors use a pale grey plug for the upstream sensor and a black plug for the downstream sensor. Some of the cheap replacements use a darker grey plug and can be mis-identified by the supplier. The original plugs are subtly different, and shouldn't fit wrongly, but they can be forced (but don't !).
Fitting will involved removing the inlet manifold as it kind of 'folds-over' the bank one cylinder head. While that is off, you might as well get the spark plugs changed (use very good ones) as well and also the gaskets/o-ring seals on the manifold. You will need the correct tool to remove and re-fit the oxygen sensor, but it is not really expensive and should serve you all your motoring life. My set of 3 only cost me a tenner off e-bay !
Good luck with this - do take the time to check the connectors & fuses before you start dismantling things !
P1646 indicates some problem leading to bad readings from the bank 1 upstream (upper, before the cat) oxygen sensor. It could be a problem with the sensor, the wiring, or even the fuse which supplies current to the heater in it. Are you getting any other codes as well ?
Bank 1, on the sideways-mounted V6 engine, is up against the bulkhead. You will see the two electrical connectors for the bank 1 sensors pretty much amidships on the bulkhead just slightly to the left (looking forwards) towards the brake servo.
Do avoid cheap replacements at around £30 or so. Good ones, up to Jaguar standards, will cost you between £70 and £90 depending on supplier. I learned this the hard way !
The original Denso sensors use a pale grey plug for the upstream sensor and a black plug for the downstream sensor. Some of the cheap replacements use a darker grey plug and can be mis-identified by the supplier. The original plugs are subtly different, and shouldn't fit wrongly, but they can be forced (but don't !).
Fitting will involved removing the inlet manifold as it kind of 'folds-over' the bank one cylinder head. While that is off, you might as well get the spark plugs changed (use very good ones) as well and also the gaskets/o-ring seals on the manifold. You will need the correct tool to remove and re-fit the oxygen sensor, but it is not really expensive and should serve you all your motoring life. My set of 3 only cost me a tenner off e-bay !
Good luck with this - do take the time to check the connectors & fuses before you start dismantling things !
#10
04-13-2021, 12:29 PM
Senior Member
lower radiator hose help
My 1989 XJS fuel inj. blew a hose,, it's the driver side lower hose. Is it a stinker to replace? I'm pushing 83 and getting down there is very hard, 100 miles away from Jag dealer, dealers hear just shake their heads.
Any tips, advice or help appreciated.
Thank,
Dick Campbell (DickC)
Any tips, advice or help appreciated.
Thank,
Dick Campbell (DickC)
#12
11-23-2023, 02:48 PM
P1646 Code
stevie: Pictures with locations of all 4 oxygen sensors are in this thread: https://www.jaguarforums.com/forum/x...-where-129374/
The error code P1646 is telling you to replace the upstream oxygen sensor on Bank 1, the firewall side. It's easy to see, but not so easy to reach with a socket and breaker bar.
To locate this sensor, open the hood and stand by the left front wheel - the UK passenger side. Look for two electrical connectors mounted on the firewall next to the power brake booster, towards the center of the car. One is light grey, the other black. These are for the upstream (grey) and downstream (black) oxygen sensors. Trace the wires from the grey electrical connector down between the engine and the firewall to the upstream oxygen sensor. This sensor needs to be replaced because it has an electric heating element (like a toaster) that goes back with age.
The Bosch replacement part # is 15627: Amazon.com: Bosch 15627 Oxygen Sensor, OE Type Fitment: Automotive
The Denso replacement part # is 234-9029: Amazon.com: Denso 234-9029 Air Fuel Ratio Sensor: Automotive_
To remove and install the sensor, you'll need a special 7/8 inch socket, like a spark plug socket, but with a slot cut for the sensor's wires: Amazon.com: Lisle 12100 Oxygen Sensor Socket: Automotive_
This post also has pictures of the special socket: https://www.jaguarforums.com/forum/x...0/#post1059714
In the US, we often borrow special tools like this from the local auto parts store. Hopefully you can borrow one as well.
As I mentioned, this sensor is easy to see, but not so easy to reach with a socket and breaker bar. This post describes one way to reach it: https://www.jaguarforums.com/forum/x...1/#post1247370
If you have any questions, let me know and I'll try to walk you thru it. It's not that difficult, but does take some patience and persistence
Good luck.
The error code P1646 is telling you to replace the upstream oxygen sensor on Bank 1, the firewall side. It's easy to see, but not so easy to reach with a socket and breaker bar.
To locate this sensor, open the hood and stand by the left front wheel - the UK passenger side. Look for two electrical connectors mounted on the firewall next to the power brake booster, towards the center of the car. One is light grey, the other black. These are for the upstream (grey) and downstream (black) oxygen sensors. Trace the wires from the grey electrical connector down between the engine and the firewall to the upstream oxygen sensor. This sensor needs to be replaced because it has an electric heating element (like a toaster) that goes back with age.
The Bosch replacement part # is 15627: Amazon.com: Bosch 15627 Oxygen Sensor, OE Type Fitment: Automotive
The Denso replacement part # is 234-9029: Amazon.com: Denso 234-9029 Air Fuel Ratio Sensor: Automotive_
To remove and install the sensor, you'll need a special 7/8 inch socket, like a spark plug socket, but with a slot cut for the sensor's wires: Amazon.com: Lisle 12100 Oxygen Sensor Socket: Automotive_
This post also has pictures of the special socket: https://www.jaguarforums.com/forum/x...0/#post1059714
In the US, we often borrow special tools like this from the local auto parts store. Hopefully you can borrow one as well.
As I mentioned, this sensor is easy to see, but not so easy to reach with a socket and breaker bar. This post describes one way to reach it: https://www.jaguarforums.com/forum/x...1/#post1247370
If you have any questions, let me know and I'll try to walk you thru it. It's not that difficult, but does take some patience and persistence
Good luck.
Curley
#13
11-23-2023, 02:54 PM
P1646 code
I have the P1646 code. I replaced the upstream O2 sensor. Then, I replaced it again with an expensive one,($200). I then replaced all the relays in the trunk. And STILL, that code comes right back. This is a 2000 XJ8 VP. Aside from starting a big fire under it, What is left or what can I do to get rid of this code? I just don't get it.
PLEASE HELP.....
PLEASE HELP.....
#15
11-24-2023, 08:20 AM
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Curley, did you erase the codes following the sensor replacement? The codes will remain in the car and will leave the dash light on for a number of starts after the condition has cleared.
If this still leaves you with the error codes, you then have a wiring problem. I would first start with accessing the plug to the upstream sensor and sticking 2 sewing pins in beside the red wire with a blue stripe (pin 1) and the white wire with a green stripe (pin 2). With the engine running, measure with a multimeter the 2 sewing pins. The pins should be inserted until you feel them hit something solid (this should be the wiring). The multimeter should jump up to something around 11-12 VDC. If it does, then we know the heater circuit is working. If it is down around 0 VDC, then most likely you have either a failed wire or the ECU is toast. Assuming you have 0 VDC, you will need to go to the ECU and repeat the check on the same colored wires, but now Pins 1 and 8 respectively. If you still get 0 VDC, then you have a bad ECU. If you are getting 11-12 VDC, then you have a bad wire. If you have a bad wire, measure between the ECU and the O2 sensor plug on the same color wire (each end of the red wire for example). If you get 0 VDC, then that wire is good. If you get 11-12 VDC, that wire is bad. Repeat for both the red and white wires. I doubt it is the white wire as it feeds all 4 O2 sensors, but it could be the last few feet where it breaks off and heads to the upstream sensor.
If the heater side checks out good, then you will need to pull the plug for the ECM and find pins 4 (red wire) and 10 (yellow wire). Do a resistance check between the 2 pins. Set the multimeter to the 2K scale. If you get a reading of a few hundred ohms, the sensor and wiring is good and your problem is the ECU. If you get an indication of "OL" (or whatever your meter says when it is a very high resistance), then you have a bad wire. This is where you will have to go to each end of the wire, do a resistance check and you should get either a very low resistance (under 5 ohms) or a very high resistance (OL on the meter). The wire that says OL is your bad wire and will need to be repaired.
If you need assistance in how to repair a wire, let me know. I have to do this on a routine basis at my work and I will give you some helpful pointers to get something that will be a repair to outlast the car. the big key is getting a good seal on the new wiring where you are joining the 2 wires together. You let water get inside the joint, you will be back at this in another few years.
If this still leaves you with the error codes, you then have a wiring problem. I would first start with accessing the plug to the upstream sensor and sticking 2 sewing pins in beside the red wire with a blue stripe (pin 1) and the white wire with a green stripe (pin 2). With the engine running, measure with a multimeter the 2 sewing pins. The pins should be inserted until you feel them hit something solid (this should be the wiring). The multimeter should jump up to something around 11-12 VDC. If it does, then we know the heater circuit is working. If it is down around 0 VDC, then most likely you have either a failed wire or the ECU is toast. Assuming you have 0 VDC, you will need to go to the ECU and repeat the check on the same colored wires, but now Pins 1 and 8 respectively. If you still get 0 VDC, then you have a bad ECU. If you are getting 11-12 VDC, then you have a bad wire. If you have a bad wire, measure between the ECU and the O2 sensor plug on the same color wire (each end of the red wire for example). If you get 0 VDC, then that wire is good. If you get 11-12 VDC, that wire is bad. Repeat for both the red and white wires. I doubt it is the white wire as it feeds all 4 O2 sensors, but it could be the last few feet where it breaks off and heads to the upstream sensor.
If the heater side checks out good, then you will need to pull the plug for the ECM and find pins 4 (red wire) and 10 (yellow wire). Do a resistance check between the 2 pins. Set the multimeter to the 2K scale. If you get a reading of a few hundred ohms, the sensor and wiring is good and your problem is the ECU. If you get an indication of "OL" (or whatever your meter says when it is a very high resistance), then you have a bad wire. This is where you will have to go to each end of the wire, do a resistance check and you should get either a very low resistance (under 5 ohms) or a very high resistance (OL on the meter). The wire that says OL is your bad wire and will need to be repaired.
If you need assistance in how to repair a wire, let me know. I have to do this on a routine basis at my work and I will give you some helpful pointers to get something that will be a repair to outlast the car. the big key is getting a good seal on the new wiring where you are joining the 2 wires together. You let water get inside the joint, you will be back at this in another few years.
#16
11-24-2023, 11:10 AM
#18
11-24-2023, 08:58 PM
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Curley, when you say "right" side, are you saying that as you are standing in front of the car, the O2 sensor on your right side? If so, then you replaced the wrong sensor. Being british in design, the "right side" is actually on your left side (passenger side) as you are standing in front of the car.
Follow this link and see post #2. Cylinder numbers system - Jaguar Forums - Jaguar Enthusiasts Forum
Follow this link and see post #2. Cylinder numbers system - Jaguar Forums - Jaguar Enthusiasts Forum
#19
11-27-2023, 02:04 PM