Took tje girl out for some air and the check engine lite came on. Did the key off 10 secs key on no fault code, only 2 positions on the key on, start. She did stall and i jad to floor tje pedal to clear the system and made it home, but i still can’t find an answer to the np fault code to troubleshooy further?any ideas?
Fyi I am still running on new fuel with sea foam after cleaning the tank and installing a new fuel pump and filter so that may be the reason for the stall problem but not for no fault code display.
Did you depress the VCM button with the key in ACC position?
Here is a page from ENGINE MANAGEMENT book I got from my copy of the Jaguar repair manual.
This is a .pdf copy from the green 3 ring binders from ‘back-in-the-day’.
bobXJ40VCM.pdf (690.7 KB)
bob
Yes, I stopped the engine, waited 10 to 15 secs, turned on ignition and puhed the vcm, it just continues the usual cycling of bulb failure, low washer fluid, etc.
No one mentioned to pushAND HOLD vcm. Now I get fault code 3 which should be failed coolent tep sensor, however dash temp gauge is reading normal.
David,
The cabin temperature gauge and the EMS temperature sensor are on different circuits served by different sensors so a working temp gauge on the dash does not mean that you don’t have a code 3 problem.
The temp gauge sensor has one Orange/pink wire, the EMS coolant sensor has 2 wires, Blue/violet and Black/yellow
Pardon my ignorance(or lack of knowledge) but what is an ems temp sensor and what is it’s purpose?
The EMS sensor is the engine management sensor.
The engine in the XJ40 has two engine temperature sensors, both mounted on the top of the thermostat housing at the front of the engine. One of these sensors is a brass coloured thing which has has one wire coming from it attached by a spade connector. This sensor works the temperature gauge on the dash.
The other temperature sensor has a rectangular top which has a two pronged plug attached to it. On my car at least, the plug is brown and the top of the sensor itself looks to be made of black plastic. This sensor is the one the engine management uses to determine the temperature of the car. It is entirely possible as Bryan says to have a faulty engine management sensor causing all sorts of running problems by misinforming the engine management of the engine’s temperature, but a working cabin temperature gauge sensor telling you (but not the engine management) what the real temperature is.
Yes I wondering why there was 2 sensors up there! Thanks for the info. Is there any way to check the ems sensor? Perhaps some info in the archives?
Thanks Bryan ,after checking the link I think I will just try to find a new one!