P1646 confusion
#61
04-28-2015, 07:06 AM
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Last edited by RJ237; 04-28-2015 at 07:08 AM. Reason: information error
#63
04-30-2015, 01:20 AM
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#64
04-30-2015, 07:45 AM
P1646 $1647
Thanks for the insight guys...appreciate it. Given this car has two fuel pumps I am curious what the symptoms are when the secondary pump fails. The car drives well when I get on it, and I can't sense a lack of preformance, only a slight roughness when idling and a small amount of vibration otherwise. Thought I might spell out the steps taken thus far as I may have missed something. Any insight is appreciated.
1. Got MIL light after starting (car was not started for two days prior). Did not get "Restricted Performance" message.
2. Got P1646 on scanner..no other faults. Care drives well even when I get on it. Seems the car is idling a bit rough.
3. Pulled relay. Got the restricted performance message.
4. Replaced relay, same P1646 on scanner. That's wher I am at now.
So does anyone have an idea what to expect with a secondary fuel pump failure that I can detect? Did I miss something? Pulling the tank seemd like a pretty big mistake if I am wrong.
1. Got MIL light after starting (car was not started for two days prior). Did not get "Restricted Performance" message.
2. Got P1646 on scanner..no other faults. Care drives well even when I get on it. Seems the car is idling a bit rough.
3. Pulled relay. Got the restricted performance message.
4. Replaced relay, same P1646 on scanner. That's wher I am at now.
So does anyone have an idea what to expect with a secondary fuel pump failure that I can detect? Did I miss something? Pulling the tank seemd like a pretty big mistake if I am wrong.
Hey guys These faults are nothing to do with fuel pumps faults or relays.
Had this problem myself.
The p1646 is the left bank (Driver side) upstream (one at the top behind the rad tank with black connector) O2 sensor fault. The p1647 is the heater failure on the same sensor. Generally the heaters fail In the O2 sensor.
Shame really as the heater section is only really effective for the first few minutes. Kind of acts as an old chock did and makes it run rich until its warmed up. Then the ECU continues to monitor the current on the heater side. When its zero a fault is flagged.
You can confirm this by checking the circuit on two of the four pins on the O2 sensor at the connector. Cannot remember the wire colors or pins but its in the manual. I think its the black wires there should be around 4ohm resistance. If its open the heater had died generating the fail.
Thats why it runs a little frrough at ststartup and idle and fine other time.
#65
04-30-2015, 07:58 AM
Veteran Member
On a 2002 and earlier XKR, well, it depends. Read the whole thread if you have one of these cars.
Last edited by WhiteXKR; 04-30-2015 at 08:04 AM.
#66
09-07-2015, 09:25 AM
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P1646 code Jag X Type
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
#67
09-07-2015, 09:06 PM
Veteran Member
It would be best that you ask your question over at the X-Type area.
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
#68
09-27-2017, 03:03 PM
Today I was working on a 2002 XK NA and came to this topic and to confuse you guys even more I had to share this with you.
The car came in with the check engine light so I hooked up my laptop with IDS (which is included in the latest version off SDD) and came to fault code
P1646 - Secondary fuel pump relay
Because it is not a S/C car and not a common fault (a relay as a fault code) I was suspicious! Then I hooked up my WDS and I saw:
P1646 - heated oxygen sensor control module Bank 1 open or shorted
So it is not only us who can't figure the logistic of fault codes, even the original Jaguar diagnostic computers can be wrong.
I unplugged the upper lambda sensor from bank 1 (right hand) and couldn't measure any resistance over the heater wires, will replace the sensor next week.
The car came in with the check engine light so I hooked up my laptop with IDS (which is included in the latest version off SDD) and came to fault code
P1646 - Secondary fuel pump relay
Because it is not a S/C car and not a common fault (a relay as a fault code) I was suspicious! Then I hooked up my WDS and I saw:
P1646 - heated oxygen sensor control module Bank 1 open or shorted
So it is not only us who can't figure the logistic of fault codes, even the original Jaguar diagnostic computers can be wrong.
I unplugged the upper lambda sensor from bank 1 (right hand) and couldn't measure any resistance over the heater wires, will replace the sensor next week.
#69
09-28-2017, 01:36 AM
Veteran Member
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