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Dear Forum,
I have been receiving excellent advice and help from Cambo down in Oz, but I appear to have lost touch with him - Perhaps he is very busy or away? Or perhaps he has become fed up with my problem - I know I am!
see post: https://www.jaguarforums.com/forum/x...-209820/page2/
Anyway, I need to have my Jaguar emission-tested by 10th November or I will be fined for every month thereafter, irrespective of whether the car is on the road or not!
CAMBO POSTED: Next step is to unplug the harness at the ECU and look at the resistance between the two wires; the 5V sensor supply, and the signal return to the ECU. There should be no continuity between them when the ECU is unplugged. If there is, well that's your problem....
Okay (at long last I am at the ECU) Cambo, there is no continuity between the 5V supply and the signal return?
So, Pinpoint test G20688t7 - Check FRP Sensor Signal Circuit for high resistance - Is it greater than 5 ohms? Answer, no, 1.0 ohms. PASS G206886t8 - Check FRP signal circuit for short to high voltage - Is it greater than 3 volts? Answer, Yes, 5 volts FAIL G206886t9 - FRP Signal circuit to Ground - Is resistance less than 10,000 ohms? Answer, Yes, Was 5.01 ohms when ECU was plugged in; now shows no reading with ECU unplugged? FAIL
PLEASE, what should I try next? Ford here in Dubai want £100 for the OEM sensor; I've already paid £40 plus £25 shipping from the UK for what must obviously be a Chinese copy? Could it be this sensor at fault? Why blame this sensor when the signal circuit is high when it is disconnected? Could this be a short from supply pin 1 to Ground (with the signal wire picking up the 5 volts from Ground)? Should I try probing the ground pin at the sensor connector and the signal pin at the ECU connector for continuity? EDIT: CHECKED: NO CONTINUITY. Would that tell me? If so, what do I do, please?
Hello Meiron1. Thanks for you reply - I was starting to feel a little bit lonely!
No, the original (Ford) sensor is completely U/S. When the nipple broke off it came away with a chunk of the 'box' containing the sensor. It was all very brittle. I superglued it back and then sealed the join with epoxy, but the internal diaphragm had also been damaged.....I could blow straight through the sensor; obviously that is no use - Would release any pressure (and fuel) in the fuel rail directly into the inlet elbow via the vacuum hose! I am just going to have to wait to see if any of our 'Electro-Technos' will row to my rescue!!
Please see attached wiring diagram: If there is continuity between the Ground pin on my sensor connector and pin 019 at my ECU, does this mean that my sensor Ground is good? UPDATE: I have continuity between sensor pin 3 (connector) and pin 073 (ECU). I cannot find any continuity between 5V supply pin 1 (connector) and pin 012 (ECU) or between Ground? pin 2 (connector) and pin 019 (ECU). This is even more puzzling because when the ECU was connected I definitely had 5V at connector pin 1 (correct voltage) and 5V at pin 3 (too high, should not be more than 3V)?
I am stumped, please help!
Hello Meiron1,
Thank you but I have already bought a UK sourced Chinese copy of the Ford sensor fitted to my car and it does not work? https://www.britishparts.co.uk/jagua...pressure-p5020 Now, it either does not work because it does not work - because it is not a genuine Ford part or it does not work because the wiring to the sensor is faulty. My problem is twofold: 1. the wiring I have exposed (so far) appears to be pristine. 2. I am getting conflicting information from the Workshop Manual Pinpoint tests? My Fuel Rail Pressure Sensor (FRP) sensor connector pin 3 (sensor signal) has 5 Volts (should be no more than 3 volts) when sensor is disconnected but it is connected to the ECU and the battery is connected. My sensor connector pin 1 (supply) also has 5 volts when sensor is disconnected but it is connected to the ECU (and the battery is connected). When the ECU is disconnected, I have continuity between pin 3 (connector sensor wire) and pin 073 (ECU), but NO (apparent) connectivity between sensor connector pin 1 (5V supply) and pin 012 (ECU), despite the fact that there is 5V when the ECU and the battery is connected? PLEASE, I REALLY NEED SOMEONE TO EXPLAIN TO ME WHY I SHOULD SPEND ANOTHER £100 FOR A GENUINE FORD SENSOR TO (PERHAPS) SOLVE MY PROBLEM, GIVEN THE CONFLICTING PINPOINT TESTS?
Meiron1 - I welcome any help you can get me regarding the electrical questions here!
Please, does anyone have any suggestions for me? Do I have a short between the Supply and Ground? So that when the ECU and the FRP Sensor are both connected and the ignition is on I get 5V between Ground and Supply and also 5V between Ground and Signal (should be no more than 3V); this could account for the excessive voltage at the signal pin (to Ground) and the zero continuity between ECU (pin 073) & Connector (pin 1) Supply Pins when the ECU is disconnected? Could it also account for the 'Less than 10,000 ohms between Signal and Ground (reading was 5,000 ohms - Well 5.01 ohms anyway). I really am shooting in the dark with this Auto Electric stuff!!
If so, what must I do about it, please?
Or do I simply need another Sensor - a Ford Sensor?
Hello Meirion1. Thank you. I've taken your advice and sent the vendor an eBay message, asking them if they would check whether the sensor is FoMoCo. They have not replied yet, but my wife is in the UK until 14th November and at my request she rang them for me and they will check and get back to her today. They will not be able to post it to me by Royal Mail International signed because there is no individual mail delivery system here in super modern Dubai! So, it's either another £25 or so for my wife to courier it to me or I wait until 14th November for her to bring it to me (I have to have my emissions test done before the 10th to avoid fines)?
Nevertheless, I still thank you for taking the time and trouble to post me. I have not received any further responses to my electrical questions and since I am operating way outside my own knowledge base when it comes to auto electrics, your post has decided me to abandon my clueless hacking of my wiring harness to pieces and wait for another new sensor with my fingers crossed!
Again, thank you.
your mistake was buying cheep .
don't bother with chinese sensors , your asking for trouble . the genuine ford ones are only $80 usd .
i bought one in august for the same issue . and is working perfect again .
there is a thread in the s type forum of all the cross reference ford /jaguar parts .
in that list is all the compatible ford fuel reg part no#s that work on the s/c jags .
they range from $80 way up . and the same part no# when searching jag regs are over twice the price .
you dont need to ask if its fomoco it clearly says it on the side of the part.
Datsports, thank you for your post.
I am forced to agree with you (see my thread number 5 above). I did not realise that the part I bought to replace the one in the photo was not a genuine Jaguar/Ford part until it arrived here in Dubai: (https://www.britishparts.co.uk/jagua...pressure-p5020). I have seen the Ford sensors you mention for $80 etc, but unfortunately I have not found one of them prepared to ship to the UAE!
However, I am not prepared to pay a further £100 to the Ford dealer here in Dubai for a genuine part that may still not work given the conflicting results I am getting from my pinpoint tests between the ECU and the Sensor Connector? I am hoping to buy a second-hand sensor which was (again, hopefully) removed from a Jaguar in the UK for £30 and have it brought to me by my wife, who is in the UK until the 14th. In the meantime, I need to decide if you are not just right, but so right that (in my absence of any clue regarding further checks on the wiring) I might just as well spend the next week buttoning back up my partially stripped wiring harness, and restoring the Cabin Air filter container box etc, etc, the Cowl Vent Screen and Wiper Arms etc, etc, reconnecting all the other sensors, injectors etc...….
And I still don't understand why any sensor, be it a FoMoCo or a FoLessCo is going to work when I have 5V in my signal wire when the sensor is disconnected? Perhaps when some kind soul of a Jaguar owner is next under their bonnet or hood (obviously not likely to happen very often) they could unplug the sensor and see how many volts they have between the blue Signal wire and the Ground wire (in the middle of the three)?
Datsports, I mean no disrespect to you whatsoever and I am grateful for your post, but your problem may have been good wiring and a failed sensor? Nevertheless, I will still take yours (and a number of other Forum Members) advice and buy another (but Ford) sensor!!
the 5v is required for the sensor to function . and is sent from the ECM . it will be sent with or with out the sensor plugged in .
correct i had no wiring issues , although the fault code for the dead FPR sensor or IP Sensor . in my case was P0191.
and the fault description in JTIS for all possible IP/FPR sensor issues (p0191,p0192,p0193) would most certainly have you looking at the wiring first .
and replace the part if necessary .
however i found it easier to just try a new part / used part first , in fact Cambo's old original one , if i remember it lasted about 3000km and died .
and threw the same code again . i thought i was in some trouble ,
but id already bought a new genuine ford one in the mean time , and 20mins later she was away again . has no problem now .
[QUOTE=Datsports;1984818]the 5v is required for the sensor to function . and is sent from the ECM . it will be sent with or with out the sensor plugged in .
Thank you Datsports.
Yes, I understand that 5v is required for the sensor to function. I have 5v between the supply wire and Ground with the sensor unplugged. My problem is that I also have 5v between the signal wire and Ground with the sensor unplugged (pin test says no more than 3v should be present)? Also, with the ECO unplugged, I have continuity in the signal wire but none in the supply wire? I believe I also have no continuity in the Ground wire, but I do not know whether or not I am testing it correctly - With one probe on the sensor connector's Ground and the other on pin 19 at the ECU - No continuity?
I guess I am just going to have to be patient and wait for my trouble and strife to return to me clutching a Ford sensor!
Datsport, when you next talk to Cambo, please thank him from me for all his help and above all, for his patience!!
ok understood , no continuity is not good .
but , if your not sure of your tests , or procedure , then it would not hurt study some more and to go over your work .
(i.e correct pin outs for you specific car / different multimeter and so on ,from the start) .
whilst you are waiting for your correct part .
i would not trust that chinese part , let alone for trouble shooting . i've learned that lesson
i just looked at cambo's post 25 in the other thread . i think you have miss interpreted the test he instructs to carry out .
regarding continuity .
especially after reading this again ;
with the ECO unplugged, I have continuity in the signal wire but none in the supply wire
im sure your not on the same page .
sit back and wait for a correct part for a start . you've done your self no favors persevering with the inferior sensor .i think
ok understood , no continuity is not good .=left but , if your not sure of your tests , or procedure , then it would not hurt study some more and to go over your work .=left (i.e correct pin outs for you specific car / different multimeter and so on ,from the start) .=left whilst you are waiting for your correct part . =left i would not trust that chinese part , let alone for trouble shooting . i've learned that lesson =left Cambo knows he's Appreciated round here . .
i just looked at cambo's post 25 in the other thread . i think you have miss interpreted the test he instructs to carry out .
regarding continuity .
especially after reading this again ;
im sure your not on the same page .
sit back and wait for a correct part for a start . you've done your self no favors persevering with the inferior sensor .i think
Thanks Datsports - I am going to wait for the Ford sensor.
Just to let you know, I switched my multimeter to continuity (the little sound signal wave-like symbol) and put one probe on ECU pin 073 (signal) and the other on sensor connector pin 3 (signal) and got a beep and screen shows 0.000. I repeated this for ECU pin 12 (supply) and sensor connector pin 1 (supply) and got no beep and screen shows 1; that is how I am reading no continuity on supply; yet (as we already know) if I reconnect the ECU, I get 5v at both supply to Ground and Signal to Ground.....Go figure? Could it be that the (no continuity) supply is leaking to Ground and as a result, when measured at the sensor connector you get 5v from Ground to Supply and also 5v between Ground and Signal? Or (more likely) am I completely wrong?
I'll wait for the Ford sensor!
Datsports, Did as you suggest in your thread 13. Took into account what you told me in your thread 14. I have no continuity between ANY of the sensor connector pins with the ECU disconnected; correct me if I am wrong (probably) but what both Cambo and you are saying is that despite ANY other Pin Test test readings I have got, this means that there cannot be ANY short circuits between the ECU and the Sensor Connector? Correct? Despite the fact that I have no continuity between the ECU supply pin and the connector supply pin? If so, it just proves to me that (despite the Pin Test failure readings I have had) I need to get better at LISTENING to what you guys are saying, instead of just going off on one!
yes i believe cambo's instructions were to prove there are no ( crossed wires) or shorts between any wires .
and it now sounds like there is not any .
were as to check no wires are broken -
a fool proof test even with out a diagram or pin out . would be to test continuity by probing 1 wire at a time at the sensor loom plug.
and with the other probe check every ECM plug pin . separate test per sensor wire .
there should only be one pin at the ECU plug at a time with continuity . any more than one would show a short . any less than one would show a break .
Hello Datsports,
Firstly, I have bought the second hand Ford FRP Sensor you kindly provided the link for and my wife will bring it to me on 14th November. Now that I have actually done what I was told, we know that none of the three FRP sensor wires are crossed! As you suggested (told me to go back through everything) I am going to continue to try to find out why (given the above) my FRP circuit has exceeded the correct signal wire voltage (5v should be less than 3v) and failed the signal wire to ground resistance tests (5,000 ohms instead of 10,000 ohms). Also why there is no continuity between the ECU power supply pin 12 and the connector supply pin 1, even though there is 5v at the connector pin when the ECU is connected and the ignition on? I notice from the wiring diagram that the FRP sensor shares its power from pin 12 on the ECU with the power pins for the MAP Sensor and the Throttle Position Sensor, both of which are accessible. If I check the continuity between their supply pins and pin 12 on the ECU, I should find continuity? Am I correct? If I do find continuity for those sensors, yet none for the FPR Sensor, could that point to a broken FRP supply wire, between the connector and the splice where these sensors are joined together? Up behind the engine, I think? What to do you think?
11-02-2018, 03:41 AM
Fuel Rail Pressure Sensor
