Is there a particular year and model car you are asking about, or should I guess at random? The post appears in XJ6, and I think that is meant for models older that X300.

Are you in the U.S?

 

P0727-Engine speed input signal missing. Meaning engine stalls, key still on, ECM still powered up, looking for that signal.....
P1775-MIL request from TCM. Usually related to stalling.

Causes.
No. 1 Stuck open EGR valve. Probably the most likely candidate.
No. 2 Crank Position Sensor. Commonly replaced for these codes, usually never fixes it.
No. 3 I've seen these codes pop up if the car runs out of gas, overheats, fuel pump fails, or anything that could cause that engine to stall.

The engine harnesses, to my knowledge, aren't available for the X300 anymore. You'd have to search the scrap heap to find one. Or steal it off your buddy's car.

 

Hey Po,

I didn't look at these code, I presume you are sure they are for a six?

Interesting about the fuel pump/ runs out of gas comment, I have never seen or read about DTC's being logged in either scenario for X300/ X308.

I had a no-start on an X300 not too long ago, the ECM had a pin rotted off and the connector was nasty. ECM is deemed as a "non-rebuildable core" in this case, harness hacking as you described would also have been necessary. The guy's car was wrecked, so he didn't want to pay me to get it running.

 

Yeah they aren't listed either in my factory dtc booklet. I know these codes well. They were common on the 300s 6 cyl. Well hang on a sec..... The 1775 is listed with the exact exp. I gave. The 727 is not listed in this book. I do have another source in which to check.

 

Anything that causes the engine to stall has the potential to cause those codes. Not always bit it has happened with me.

 

Roger that, thanks. Either way, our random guest needs another set of eyes to look at his car. Even if it needed a $2200 ECM and an $800 harness, he can buy a whole parts car for a grand and send that one to the crusher after he hacks off what he needs for his.

 

I thought you guys should know........."P" codes are not manufacture codes they ore OBDII Standard code which means that they never change in description. When a manufacture doesn't use the code in their diag trees it will show up as "undefined code".
I had a few of these where it turned out to be the Transmission selector switch that caused the P1775 code. No data exchange between ECM and TCM because of internal fault in the switch.

30 year "ASE" Master Auto & Master Truck Technician

 

Thanks for the lesson, I feel so embarrased about all those cars I have sent to the crusher since 1977. If only your guidance had saved me sooner....Nice font too, it looks so authoritative.

I have a proprietary WDS, I read Jaguar factory code descriptions (as opposed to generic P code descriptions) of any DTC's present, and I fix the car. Forgive me for not committing superfluous knowledge to memory.

But it's nice to see we have a new expert, feel free to offer your sage advice to the throngs of people here who need it. You can even do it in CAPS if you want.

 

Wasn't trying to flap my wings or ruffle any feathers. I started repairing Fiat and Triumph Autos in 1974....there were no scanners and very little Dealer Training Available. I have owned close to 67 cars and 33 Trucks in the 30 years of my life as a mechanic. I was only trying to help. Sorry if I stirred things up. CAPS is like shouting and I never do. May the peace that excells al thought be with you.

 

I don't read where I questioned your experience, or asked for a resume...I used to dyno test turbocharged Cosworth V8 IndyCar engines with Bobby freakin' Unser yelling in my ear, but it doesn't mean I can fix this guy's Jaguar over the internet. I thought that's what we were talking about.

 

Dude all that is very cool.............and no harm was intended.
I didn't start off on the right foot. New to this whole Forum thing and forgot my place. (4 teenagers, still married, still nagged and sometimes it rubs off)

 

There's lots of people here asking lots of questions. Most of them don't understand the answers, but you're welcomed to try helping as many of them as you think you can.

 

Thank you, I look forward to the challange.....Not perfect, but willing to try.LOL

 

I just had both these codes set on my 1996 4.0 XJS. Going to remove the EGR tonight and see if it is carbon'd up.

 

My 1996 XJ6 randomly dies (or sputters) at low speed, or accelerating from a stop. I have spent over $2,000 trying to fix it. New Fuel Pump, lots of short's fixed, still the same problem. It currently has a P1775 code. Haven't checked the EGR valve, or Transmission sensor. Would love some feedback.

 

The P1775 TCM code is set when the engine stalls. It is a result of the stalling, not the cause. Remove the EGR valve (just two bolts and a electrical connector) and see if the pintle valve is stuck and carboned up. It should move freely when pushing it in. If it is hanging up and doesn't close properly this could be your problem.

 

And lets not forget about the intermittent crank sensor faulure that happens when heated up that burned me on my own xj6 4 years ago. Would just stall after driving and no crank sensor code. When ohmed it out is was fine, until i heated it with a heat gun then it failed, replaced it and "my" car has been fine since. Just to throw that out there for those that have forgotten the issues on these 15 yr old cars

 

I replaced the spark plugs last night and vualla! No more stalling, or sputtering. It was the spark plugs the entire time. I'm an idiot.

 

Hey PoBoyBlues...........EGR valve was OK. I cleaned the Crank Sensor and it ran 20 minutes longer than it did previously. I'm replacing it tomorrow, I'll let you know how it works/doesn't work, Thanks for the help! Much appreciated!