OBD11 code erasure

[venge]

Hi

Sorry if this is a tad long winded but...

I purchased an OBD11 code reader several months ago which has proved to be a really good investment. However, I recently had a problem with the car going into 'restricted performance' and when checking the car with the code reader it gave 2 codes P0353 (which was coil C) and P1646 (which was the lambda sensor). Having replaced both the coil and the lambda sensor at great toil and loss of knuckle skin, I took the car out only to find when it got warm it went back into 'restricted performance' again. Having got the car home I plugged the OBD11 back in only to find it was showing the same 2 codes.

I wondered if I was supposed to delete the code following the replacement parts but when I checked the manual to find out how to delete the codes, it gives the following warning: -

Caution - Erasing the diagnostic trouble codes allows the scan tool to delete not only the codes from the vehicles on board computer, but also "Freeze Frame" data and manufacturer specific enhanced data. Further, the I/M readiness monitor status for all vehicle monitors is reset to Not Ready or Not Complete status. Do not erase the codes before the system has been checked completely by a technician.

My question is... Should the codes delete themselves after the replacement parts have been fitted and if not is it safe to delete the codes using the code reader??

[J44EAG]

In my experience codes do not erase themselves after new functional components have been fitted. i don`t own a code reader other than a diagnostic disc that worked best on an old Dell which was WindowsXP based, so now clear codes by the "Hard dump" method. That means disconnecting the battery (on an S-type) for twenty minutes. Radio code and clock need to be reset using that method. As i understand it, hard dumping can be used to clear codes on X308 and XK without problems.

If the code still shows after clearance, then it is likely the fault is still present.

Mike K

[venge]

Cheers Mike, will give it ago

Much appreciated

Phil

[ptjs1]

Phil,

There's a difference between the storing of error codes and the display of warning lights / messages. Many of the Jaguar error code systems work on a "3-times valid" system. This means that if an error code is generated which itself generates a warning message, the message will stay displayed all the time that the error is valid. However, if the error code is not generated on three successive on/off cycles of the ignition, eg if no error is seen the next three times that you run the car, then the warning message will extinguish. But the original error codes will remain in the system memory.

You need to delete the original codes using your OBDII reader. Then if the warning message comes back, read the error codes again. You may see a different code.

As you probably know, Jaguars are notorious for throwing dubious codes if the battery voltage is less than perfect. Make sure you definitely have a good fully-charged battery.

Good luck,

Paul

[venge]

Thanks Paul

Phil