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I would be looking at the troubleshooting chart that you are using as I think it is taking us all down the wrong path. You have essentially a 2003 jaguar X-Type. yes, you may have gotten some of the beauty upgrades, but the electronics are from a 2003. Again, the Pin 24 for your ECM is a 12 VDC input from fuse F37 (not F36). You MAF sensor has 2 circuits inside of it. 1 is a temperature sensor. So, if you measure from pins 19 to 71 (connector disconnected from the ECM, you should get a value of under 10,000 ohms, but not less than 50 ohms. This is nothing more than a "thermistor" (fancy resistor) that changes resistance based on temperature. You can do a second check by measuring pins 4 to 5 on the MAF itself to make sure the values are the same (should be very close). Pin 1 of the MAF should have 12 VDC on it any time the key is in the RUN position. This is getting power straight from the fuse box. If you measure Pin 2 of the MAF to Pin 45 on the ECM (can also use Pin 46, wire splits and goes to both pins, would be a good check to check both), you should get under 5 ohms. If not, you have a wiring problem with that wire. Finally you should be able to measure between Pin 3 of the MAF to Pin 4 of the ECM. That again should be less than 5 ohms. If not, wiring problem.
With these checks, we can rule out the ECM as being "the problem". Lets see what we have here and then we can move on to the next issue.
sounds good will do that tm and lyk. just to confirm when cheching for ohms one led on the pin and the other on ground right?
Also all the pins starting with 19 to 71? or only those two?
Help, no, you are going to measure through the MAF sensor. So, you are going to have the red lead on Pin 19, the black lead on Pin 71.
When measuring the second wire (power to the MAF), you are going to put the red lead on Pin 2 at the maf (sensor disconnected) and the black lead on pin 45 (or 46) at the ECM.
Help, no, you are going to measure through the MAF sensor. So, you are going to have the red lead on Pin 19, the black lead on Pin 71.
When measuring the second wire (power to the MAF), you are going to put the red lead on Pin 2 at the maf (sensor disconnected) and the black lead on pin 45 (or 46) at the ECM.
I get the second part. There is no pin 19 or 71 ik of on the maf sensor?
I don't see an electrical guide specific to 2003 but looking at 2002.25 and 2004 I see the MAF temperature sensor, aka Intake Air Temperature Sensor, in both cases connects to pin 71 and pin 19 of the ECM. Leave the MAF sensor plugged in, unplug the ECM, and measure resistance from ECM connector pins 71 to 19. From thermo's post above "you should get a value of under 10,000 ohms, but not less than 50 ohms". The resistance depends on temperature so if you put your hands on the MAF sensor assembly to warm it up the resistance will go down if it is working.
alright I get what you guys are saying, but for mine I just changed the year from 2004 to 2003 jaguar on all data and the I see pin 71 going to MAF sensor and pin 19 but it branches out to so many other things would one of them not working cause false readings?
to test but multimeter on 20k ohms and then on lead on pin 19 and the other on 71 with MAF Sensor plugged in.
Pin 19 is Ground. It shares a common Ground with all of the sensors that use the same power supply from the ECM. If the MAF Ground is ok none of those other sensors matter for this measurement.
Think about it like this: Left high beam head light, rear right tail light, interior dome light, etc all get positive voltage from the battery and are grounded to the chassis. One light can go bad and not effect the rest. You can test one light at a time without worrying about all the lights having a common ground. This is the same thing except the power and ground are from the ECM, not directly from the battery. Cars do this because sensors need very steady power to work properly, not battery voltage that goes up and down.
Pin 19 is Ground. It shares a common Ground with all of the sensors that use the same power supply from the ECM. If the MAF Ground is ok none of those other sensors matter for this measurement.
Think about it like this: Left high beam head light, rear right tail light, interior dome light, etc all get positive voltage from the battery and are grounded to the chassis. One light can go bad and not effect the rest. You can test one light at a time without worrying about all the lights having a common ground. This is the same thing except the power and ground are from the ECM, not directly from the battery. Cars do this because sensors need very steady power to work properly, not battery voltage that goes up and down.
hmmm okay I get it now iam do the tests @Thermo told td or tm and will update u guys
HELP, a few things for you to consider. First off, when measuring resistance and you see "1" in the left most digit, that is telling you that the resistance is more than the current scale. So, you need to turn the dial to a high scale to get a reading. If you are on the highest scale and still have a "1' in the left most digit, then that is normally greater than 20 megaohms (20 million ohms) and in most cases can be considered an open in the wiring.
Watching the first video (the MAF sensor check from the ECU), what you saw is expected, so we know the temperature reading is getting to the ECU. So, we can check that off as possible problem.
For the second video, did you have the key in the RUN position (engine not running)? You do not say what the state of the key is and would explain the readings that you got.
As for the 3rd video proving the ground wires are good, the beeping tells me the wires are good.
The key not being found is interesting to me. I will need to go back and re-read some of the posts and see how that plays in to this. If all that you have at the moment is the car not starting, then that would be the case and the MAF sensor is not. The car should still run even with the MAF sensor disconnected as the computer will look at other values and calculate the MAF information.
I am on travel and am working long hours, so, please give me a few days to get some time to review this and see what I can find. Between the key not being seen and R4 being hot, I think we have some intersting information to be working with.
The key not being found is interesting to me. I will need to go back and re-read some of the posts and see how that plays in to this. If all that you have at the moment is the car not starting, then that would be the case and the MAF sensor is not. The car should still run even with the MAF sensor disconnected as the computer will look at other values and calculate the MAF information.
I am on travel and am working long hours, so, please give me a few days to get some time to review this and see what I can find. Between the key not being seen and R4 being hot, I think we have some intersting information to be working with.
Hmm okay sounds
As for the key it was in 2 position
key on engine off
The meter giving you a value for a fraction of a second while switching between scales is just internal changes inside your meter. Ignore that.
The reading of 2.7 on ECM pins 71 and 19 with your meter set to 20k Ohm scale is telling you the resistance is 2.7 kOhms. As thermo pointed out it should measure between 50 Ohms and 10 kOhms so that is good.
When the reading is changing between 2.72 and 2.73 ignore that. It is changing by a fraction of a percent. No DIY multimeters are that accurate.
In the 1st video you seem to be looking for the same 2.7 kOhm at the MAF sensor connector. The 2.7 kOhm came from the sensor itself, once you have pulled off the connector you no longer have that sensor in your circuit. It is important to know (and to let us know) which connectors are on and which are off when you make a measurement. For example in that first video the measurement of resistance at the MAF connector pins 4 and 5 is only measuring the resistance between 2 wires not connected to anything if the ECM connector is still disconnected. If the ECM connector is on the ECM then you are measuring the resistance of something internal to the ECM which is not important.
In the final video you are concluding the ground at the MAF is not working because there is no continuity from pin 3 to the battery negative. Pin 3 goes the the ECM pin 44. I'm not sure why you are looking for connection to ground there. I just checked mine and there is no connection to ground and my MAF is working fine.
Disclaimer: I am looking at my Model Year 2005 car and wiring diagram so maybe not the same as yours.
Last edited by dh53; Apr 11, 2024 at 12:17 PM.
Reason: add disclaimer
The meter giving you a value for a fraction of a second while switching between scales is just internal changes inside your meter. Ignore that.
The reading of 2.7 on ECM pins 71 and 19 with your meter set to 20k Ohm scale is telling you the resistance is 2.7 kOhms. As thermo pointed out it should measure between 50 Ohms and 10 kOhms so that is good.
When the reading is changing between 2.72 and 2.73 ignore that. It is changing by a fraction of a percent. No DIY multimeters are that accurate.
In the 1st video you seem to be looking for the same 2.7 kOhm at the MAF sensor connector. The 2.7 kOhm came from the sensor itself, once you have pulled off the connector you no longer have that sensor in your circuit. It is important to know (and to let us know) which connectors are on and which are off when you make a measurement. For example in that first video the measurement of resistance at the MAF connector pins 4 and 5 is only measuring the resistance between 2 wires not connected to anything if the ECM connector is still disconnected. If the ECM connector is on the ECM then you are measuring the resistance of something internal to the ECM which is not important.
In the final video you are concluding the ground at the MAF is not working because there is no continuity from pin 3 to the battery negative. Pin 3 goes the the ECM pin 44. I'm not sure why you are looking for connection to ground there. I just checked mine and there is no connection to ground and my MAF is working fine.
Disclaimer: I am looking at my Model Year 2005 car and wiring diagram so maybe not the same as yours.
@dh53 When I was checking the ports on the MAF to the ECM the ECM and MAF are both disconnected meaning like when I have to check wire from MAF to ECM both are unplugged.
and as for pin 3 on MAFS idk why I said ground that was my mistake sorry. Mine also goes to Pin 44 on the ECM
after i found out that the keys were not being recognized I called a locksmith and he said he got the keys to program but the car still didn't start gave the same codes and also showed security invalid.
Today I had someone else come and program the ecm and he could not get it it was connecting fine it just kept saying no calibration file for thos variant
That is the same problem I ran into when I was tring to program the car myself
He then tries to program the imbolizer and it just won't detect the keys i took some pictures i will add at the end. But it just does not find them.
He know is saying that there is smt wrong with the imbolizer and that i need to get a instrumental cluster.
I do have a old version of sdd v130 and abit older that runs on xp and windows 7 but the dongle i have does not work with that OS
Do you know if the ring around the ignition key is working properly? It is an antenna that picks up the number from the keyfob. If that is not working correctly, that will cause the loss of data and the key not being seen by the PATS module/instrument cluster.
Do you know if the ring around the ignition key is working properly? It is an antenna that picks up the number from the keyfob. If that is not working correctly, that will cause the loss of data and the key not being seen by the PATS module/instrument cluster.
