Hi everyone, this is my first post on the forum, but I've been using all the valuable information on it for the last month or so.

We bought our lovely 2004 (54) 2l diesel Jag estate from a private seller around 2 months ago. Within a couple of weeks it suddenly lost power, although no warning lights were showing on the dash. Usual scenario, sometimes it was fine, sometimes no power until restart. I'm going to keep this short so you don't have to read loads of stuff that is normally associated with these symptoms.

1st step, changed fuel filter (from ebay, non oem, yes, I know...) no change.

Cleaned out egr valve, checked hose between egr and MAP sensor, cleaned MAF sensor. No change.

Bought elm obd bluetooth scanner and downloaded OBD doctor to my phone, p0235 showing. One thing I noticed, when the fault was occurring, the live data would show MAP pressure around 105kpa, and would not go much above that figure. When the fault was not occuring, the reading would go much higher, as you would expect.

Removed MAP sensor. It was covered in black 'stuff', carefully cleaned it with Isopropol alcohol until the red bulb was red again. Refitted and the car was fixed. Yipee!

Went on holiday to Cornwall, covered around 600 miles and suddenly the problem was back, but once again was fine after a re-start.

Got home ordered a new MAP sensor, fitted it today, went for test drive, constant p0235 fault and no power. Check of Live data shows constant 250kpa - it does not move at all, even with the engine off but ignition on, still 250kpa.

Thinking it was a faulty new sensor, re-fitted old sensor, still showing 250kpa constant. Fitted new sensor again. Got the raving hump and came indoors!

Is this a wiring fault? Is there a massive hole in a pipe somewhere?

I'll be going out to look at it this afternoon. I'll check for free running of the turbo vanes, check the wiring at the Map plug, and look for split/loose pipes in the system.

A couple more questions if I may. How do I check the wiring at the MAP sensor plug? I take it I'll be looking for a constant +5v from one pin, a ground from another pin, some sort of voltage from the signal pin, and is the 4th pin a constant +12v? Which pin is which?

Also, when the car is idling, should there be at least some pressure in the intercooler hoses? When I was squeezing the hoses yesterday there was no pressure at all that I could feel.

It's a lovely car, but it's proving to be high maintenance so far, having also needed 2 new injectors (and another fuel filter, Delphi this time) also in the last few weeks.

With this constant 250kpa reading I'm stumped.

Please, help!

Thanks

 

Woes, I think you are on the right track. What I would recommend you do is to look at the wiring and see if all the insulation is there and then to see if the wiring makes any sudden bends (would indicate a broken wire inside the insulation). Next, remove the plug and see if the pins inside the plugs are nice and shiny or if they have a dull/rusty look to them. It may be something as simple as the connector has some corrosion inside of it leading to a high resistance.

With the indications that you have, I am thinking it has to do with the MAP sensor or the associated wiring. The only other possibility is that the ECU is failing and it just so happens that it is failing in the part that senses the intake pressure, leading to the signs that you are getting. But, because the symptoms changed when you put the new sensor in, I would start at that end first.

If you need more help, let me know.

Also, if you would, stop by the New Member Section and give us a quick intro. As you have seen, we are a friendly bunch that likes to share information and as a result, we also like to get to know one another. This will also give you a chance to learn who the movers and shakers are around these parts.

 

Thanks for your reply Thermo, I'm working on it at the moment (greasy hands as I type!)

The turbo vanes are moving freely, and I can't find any split or loose pipes on the intercooler or anywhere else.
I've removed the plug from the map sensor and am getting the following results with a tester:

Ignition on but car not running.

I'm calling pin 1 the closet pin to the drivers seat
Pin 1: ground
Pin 2: nothing
Pin 3: Initially I got a 5v reading, but having repositioned the plug for better access, now I'm getting nothing
Pin 4: nothing

Does the car have to be running to get a full set of readings from each pin?

It's starting to look like a broken wire or two at the plug. The pin receivers in the plug itself are bright and shiney. God knows how I'm going to get to the plug wiring to fix it!

Anymore help greatly appreciated.

 

Woes, the wire that is white with a green stripe should be getting 12 VDC to it whenever the car is in the RUN position. That would appear to be where you problem is stemming from. Once you figure that out, the rest should start making more sense.

 

You sure about that 12v Thermo? JTIS figures for the 2.2d are:

Pin 1 White/Green - T-MAP SENSOR PRESSURE SIGNAL, NOMINAL 0 – 5 V: VOLTAGE INCREASES AS MANIFOLD ABSOLUTE PRESSURE INCREASES
Pin 2 Yellow/Green - T-MAP SENSOR POWER SUPPLY: NOMINAL 5 V
Pin 3 White/Green - T-MAP SENSOR TEMPERATURE SIGNAL, NOMINAL 0 – 5 V: NTC SENSOR – VOLTAGE DECREASES AS TEMPERATURE INCREASES
Pin 4 Brown/Green - Ground

Those readings require the engine to be running and the T-MAP to be connected so you need a needle point on your meter lead to penetrate the insulation to take a reading.

 

My own searching reveals the same as astromorg's post but with Pin 4 (my pin 1 above) being the ground, which matches my finding for ground in my own testing.

I'll get to have another look at the car on Wednesday morning, I'll be checking for continuity on the wires from to ecu to the map plug, the pins of the ecu itself (corrosion etc) and ultimately the 5v output from the ECU as that's what appears to be missing at the moment.

 

You're right about Pin 4 Woes! An error in the cut-and-paste! Previous post edited to avoid future confusion!

 

Astromorg, I was just going off of the JTIS drawing. Maybe I was looking at the wrong component. If both of you found the same info, then I would go with that. I don't tend to work with such small diesels. Most of my experience has been on V16's that are used in train locomotives (I like the real power). Working at a power plant, we don't have a need for the small diesels.

 

Just finished fixing the car. The problem was the wires at the plug on pins 1 and 2 were broken under the insulation, proved by checking for continuity between the plug pins and ecu. Had to remove the under shield to gain access to the plug from below the car, then crimp in new wires.

The turbo is back and all fault codes are gone, hooray!

Thanks very much for your help guys

 

Thanks for posting the result.

I've added 'RESOLVED' to your thread title to help anyone searching for info on the same issue in future.

Don't forget to post some info about yourself and your vehicle in New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum forum. We like to get to know members around here!

Graham

 

Hi mate I've got the same problem as you had can you please tell me where the sensor is please mate thanks