Yes it could take a few drive cycles.
Your son needs to get an OBD reader - they should be supplied with the car.
If he's got an Android phone the best cheap solution is an app called 'Torque' and an ELM bluetooth adapter off EBay.

 

With the battery off the PCM loses its codes. So if the MIL is on you have code(s). The OBD tools are so cheap you may as well get your own. Preferably one with "live data" as any DIY and you'll need that. Elm327 is great with laptop or Android, don't know about with an iCostly.

 

Codes and CEL status are stored in non-volatile memory so a hard reset doesn't erase them.
An OBD reader, of course, will.

 

Sorry but that is NOT true for S-Types for the PCM i.e. it's not true for the codes that can be read by an ordinary OBD tool. The MIL is set by the PCM, too, so it's not true about the MIL unless you have an autobox fault of the kind reported by the PCM.

Summary: it's not true. A hard reset will erase ALL codes normally readable.

 

I'll have to take your word for it - presumably you've done it and it works.
All I can say is the S type PCM has a 'keep alive' memory just like the XK ECM.
If it doesn't store codes there then - it doesn't !

 

LOL! My wife says..."Men must always feel that their right". Let's show her guys! "We're always right!".

 

True.
I'm going to quote JagV8 though

Also, it will only clear some module(s) - the ones with volatile memory (like the RAM in a PC). It won't clear all the modules with non-volatile memory (EEROM, flash, etc).

The PCM's KAM (keep alive memory) will be cleared (so the PCM will have to re-learn a lot of needed values such as how to idle smoothly and how to detect misfires and if it's already got misfires it will learn bad stuff as being normal!). The TCM (2003/3+ cars) isn't cleared and lots of other modules also aren't. You need a dealer-type OBD tool to clear those.

Jaguar Forums - Jaguar Enthusiasts Forum - View Single Post - how to hard reset

So there !!

 

The (PCM's) KAM is powered via the main car battery so is lost on a disconnect. It's not EEPROM or the like, just RAM.

 

This isn't a point-scoring session - I'd genuinely like to know the answer.
This is a 2005 car. If it behaves like the XK ECM then the codes + CEL are in non-volatile memory.
I'd guess this is an OBDII requirement.
In your other post you said
The TCM (2003/3+ cars) isn't cleared and lots of other modules also aren't. You need a dealer-type OBD tool to clear those.
Are the codes stored there in this car?

 

I wasn't point-scoring.

Almost all the modules keep their codes across a battery disconnect. The only one I am sure loses them is the PCM. Of course it will also clear the OBD monitors (and on our cars set P1000) so from an OBD view point the car would now fail emissions test. Any code will normally re-flag either immediately or after a drive cycle or two. If there are no codes then after a couple of drive cycles the OBD monitors have generally all had a chance to run (exception with very high altitudes and a couple of other pretty rare cases) and our cars will also set a P1111 (as a pending code). Which would be an emissions OBD pass.

TCM counts as part of powertrain so should pass anything serious to the PCM to flag and set MIL, as required by OBD regulations. The TCM can also store its own data and to get it or do other diagnostics you'd need a specialist tool.

(On the pre-2003 cars the TCM doesn't exist and the PCM does gearbox as well as engine.)

Otherwise, generally speaking, each module stores its own codes. Nothing mirrors the PCM so codes cleared are gone.

However, the Denso PCM does also have some non-volatile memory and keeps some history in there for Jaguar to access, including a sort of flight data recorder (in case of e.g. an accident; you get I think it's P1582 as well). None of this is seen via ordinary OBD.

Codes in other modules should not set the MIL unless required as part of OBD (which generally they're not). So you can have dozens of codes (unlikely) and not know, if they're in the other modules.

I'm really surprised if the XK is different but I don't know which years of the XK got which version of the PCM. (It's enough keeping track of the S-Type!)

 

I know you weren't - neither am I.
Brutal is adamant (IN CAPITALS) that on the XK/XJ series a hard reset only resets trims and driving adaptions like you say above but the codes and MIL status stay.
From what you say this series behaves quite differently.

 

I still say there's no inertia switch below the glove box.

 

Have you read the ******* manual?

 

Yes, it confirms both in the text and illustration that the inertia switch is not below the glove box.

 

Do S-types have a glove box ?

 

If Brutal says it, chances are high that he's right!

There is an OBD plan (if it got that far / maybe it was passed?) to make codes non-volatile and only self-clearing so maybe the XK/XJ are part way there?

"The good thing about standards is... there are so many to choose from."

If I could find the glove box I could get the handbook that tells where the glove box is.

 

I think you'll need to download a virtual glovebox from
www.gloveboxes'r'us.com
to break out of this Brutally vicious circle we're in.
Now, I'm going away to cook supper before I get a smack from Jim for threadnapping.
I really do enjoy this Forum.

 

Nah, Jim's quite hap - ouch!

 

JagV8...interesting you mention emissions. The car failed emissions in December and my son took it to the dealer. The car refailed emissions right after due to lack of info, so he got a 30 day permit. It passed last Wednesday, and went into limp mode on Friday. I am going to have him fax me the invoice so I can post the codes and repairs. Thanks again!

 

Another Update: Car was at an Indy on November 9, 2012 to replace a bad window regulator. Tech noted the CEL was on with codes P2135 Throttle Position Sensor and P0442 Evaporative Emission control system leak. I believe the Indy must have cleared the codes to help him pass emmissions testing.

But clearly, that is why the car failed emissions in December. The Indy actually referred him to the Dealer (?) and on Jan 4, 2013 they pulled the P0442 code, plus a P0456-Evap Emission Leak as well I believe. No mention in the dealer service invoice of the P2135 code.

After a smoke test, they found a vapor leak at the cannister by the evap valve, repaired it and cleared the codes.

After waiting for the computer to store enough data, he was able to get the car to pass emissions last Wednesday, but as stated earlier, it went into limp mode on Friday.

Now, I am curious about the P2135 Throttle Position Sensor since, after reading on this excellent forum, I believe a bad throttle body can also cause the car to go into Limp Mode and cause all the related faults etc. The dealer may have missed that since the Indy cleared that code back in November, but I would think it would have popped up again by January.

So...either 1) it was just the battery and now that it has been replaced, the CEL may go off after a few driving cycles or, 2) A bad throttle body still exists, so the limp mode issue may reappear again.

I will have him take the car back to the Dealer if the CEL is still on in the next few days.

If it is the throttle body, any thoughts on costs (not a DIY for me or him). Thanks again.