1997 XJ6 - P1775 & P0727 Fault Codes

The car will run fine, but occasionally it will drop down to 500 rpm or stall out when I come to a stop. Then codes P1775, & P0727 will appear. It won't start back up for a few minutes, but when it does the check engine light, the tranny fault light is on and the car goes into limp mode. I have since parked it only to test drive it for a month. After being parked for an hour the tranny fault light turns off. Half of the time she starts as normal, but after running for 10 miles or so the idle drops to 500 rpm at idle. Half of the time she won't start unless I depress the gas pedal and she dies as soon as I let up on the gas. Is there a possibility that it is the CPS or am I being overly-optomistic? Could it be something else? Thanks for taking the time to read my post. Any feedback, intructions, diagrams and/or photos are greatly appreciated. S. D. Ketchum

Hello Ketch22,

My 1995 xjs coupe (4.0) is having the same problem. Only difference being I am also pulling P0420 and P0430 codes and the car doesn't go into limp home mode... just shuts down on occasion at idle then generates P1775 and P0727. How did you rectify this situation? Thanks in advance.

[CrustyMarine]

I'm haveing the same problem...............error code P0727? I checked the EGR and it was OK. I'm replacing the Crank Sensor tomorrow.......any other suggestions anyone? Thanks!

[xjrguy]

Originally Posted by CrustyMarine

I'm haveing the same problem...............error code P0727? I checked the EGR and it was OK. I'm replacing the Crank Sensor tomorrow.......any other suggestions anyone? Thanks!

Sometimes P0727 isn't much help on these cars. What that means is it saw no engine speed while it saw road speed. Meaning any stall will usually set P0727. If you have P1775, that only means the TCM sent a request to the ECM to turn on the Check Engine light and alert the driver.

However, a crank sensor failure causing a stall can be the culprit.

Good luck!

[genoaz]

had the same problem, was leave a hamburger joint from the drive up window, all of a sudden check engine i think came (cant remeber exactly) and the tranny default came on, engine died, coasted to a stop , heart skip a beat there, was way far from home, ok, let it set for awhile check a few things ,, got a drink scratch man head, then started right back up, drove home no lites no nothing........ok, so the only thing i did the next day after getting home was take egr valve back out,(installed a new onebut) i didnt have the right stuff to clean the 2 holes the egr valve covers,,bought a round bristle bottle washer type brush the get deep down into holes, sprayed all the gunk with throttle body cleaner and brushed the heck out of the holes, also felt like there was a big wad of stuff, final brush broke thru. been running like Top since, so the story here is clean the dang holes as far inside as you can get.

geno
1995 xj6 185k on her

[bookem]

Is there a gasket under the EGR valve. I plan to take mine of an clean it but don't want to start without neo.g able to finish.

[xjrguy]

Originally Posted by bookem

Is there a gasket under the EGR valve. I plan to take mine of an clean it but don't want to start without neo.g able to finish.

Yes, there is a gasket. P/N C2A1231

Cheers,

[etaent]

Originally Posted by Ketch22

The car will run fine, but occasionally it will drop down to 500 rpm or stall out when I come to a stop. Then codes P1775, & P0727 will appear. It won't start back up for a few minutes, but when it does the check engine light, the tranny fault light is on and the car goes into limp mode.

I have since parked it only to test drive it for a month. After being parked for an hour the tranny fault light turns off. Half of the time she starts as normal, but after running for 10 miles or so the idle drops to 500 rpm at idle. Half of the time she won't start unless I depress the gas pedal and she dies as soon as I let up on the gas.

Is there a possibility that it is the CPS or am I being overly-optomistic? Could it be something else?

Thanks for taking the time to read my post. Any feedback, intructions, diagrams and/or photos are greatly appreciated.

S. D. Ketchum

Ok so i had the same exact problem with a 96 xj6. I changed the egr valve, nothing. I changed the Idle air control valve, nothing. I changed the air filter and cleaned the MAF and nothing. I changed the TB but kept the original Throttle position sensor, and still nothing. So i got a new TPS and nothin! It wasnt until Brutal suggested that after installing the new tps i need to turn the mechanical screw that controls the air gap of the butterfly in the TB. Presto! Car is running great! so i would change the tps and goto the dealer and get an engine setup done after. Its worth every penny!