Possible wiring/Ecu/Module problems (for the experts)
#1
Possible wiring/Ecu/Module problems (for the experts)
Hi guys I am new to this form. Hope you all are doing well. So I have a technical question. I currently have no communication from my obd2 port. It is a Jaguar XF 2.7d Premium Lux. What I have done so far is ive checked the resistance between pin 6 and 14 and its 60 ohm I've also checked both grounds to the port as well as the live and all seems fine. The voltage on the high side is 2.7v and low side 2.3v so that seems fine. I am suspecting a module on the high side bringing the canbus down. Reason for me saying High is that ECU, TCM and Transmission modules not available with some others. Now my question as a noob how would I be able to determine what is causing my issue without the ability to actually scan the car.
#2
Hi guys I am new to this form. Hope you all are doing well. So I have a technical question. I currently have no communication from my obd2 port. It is a Jaguar XF 2.7d Premium Lux. What I have done so far is ive checked the resistance between pin 6 and 14 and its 60 ohm I've also checked both grounds to the port as well as the live and all seems fine. The voltage on the high side is 2.7v and low side 2.3v so that seems fine. I am suspecting a module on the high side bringing the canbus down. Reason for me saying High is that ECU, TCM and Transmission modules not available with some others. Now my question as a noob how would I be able to determine what is causing my issue without the ability to actually scan the car.
#3
Well I have tried a few 2 cheap OBD2 scanners with Torque (lite) app on my phone. Then I tried a Hawkeye the mechanic I borrowed it from says that I should use the Discovery 3/Diesel one as the engines are the same and I should be able to read the ECU using it as he has used it before on Jags and was able to read ECU and transmission modules as they are the same.
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Hard to know if the two error are related, I'm assuming if the ECU is reporting low fuel pressure then the sensor must be working. I'd guess that without a functioning crank position sensor the ECU can't send the correct instructions to the high pressure fuel pump.
Reading the manual it appears you access the crank position sensor by moving the steering gear to one side, fairly straight forward other than the 100Nm of torque used to bolt the steering gear together, someone is going to get strong arms.
#14
Good morning guys. Okay so just an update. I got the ecu out had the resistor repaired. Put it back in and pop when I turned on the ignition. So I am now trying to figure out:
1. Is the ecu shorting out?
2. Is there a dead short somewhere in the car?
The resistor that fries is the injector control module as that is the only fault the ecu reads out. Any ideas or advice would be appreciated. This has my head confused now. A fresh mind could help me find the issue. Please
1. Is the ecu shorting out?
2. Is there a dead short somewhere in the car?
The resistor that fries is the injector control module as that is the only fault the ecu reads out. Any ideas or advice would be appreciated. This has my head confused now. A fresh mind could help me find the issue. Please
#15
Do you have a short on that circuit?
It appears you do so track down what's shorted out in that circuit before reattaching the ECM.
Do you have the pin out diagrams to check the ECM plug?
If nothing is shorted out then look to the ECM. But who fixed the ECM?
Did they do it right?
Did they check for additional damage to the ECM?
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It appears you do so track down what's shorted out in that circuit before reattaching the ECM.
Do you have the pin out diagrams to check the ECM plug?
If nothing is shorted out then look to the ECM. But who fixed the ECM?
Did they do it right?
Did they check for additional damage to the ECM?
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.
.
#16
Thanks for the reply. Much appreciated. Would the short be associated only with the injectors? As it is the injector driver that keeps failing. Some ecu guy repaired it. South Africa doesn't have that many guys who know ECU stuffs that much. He came suggested by a local mechanic. Ive spoken to him and he asked that I send the ecu back to him for testing.
Looks like he repaired the blown resistor and sent it back..
My biggest question is how can I locate the short? Can it be a component somewhere thats shorting? Since its the injector driver resistor blowing does that mean look only at the injector wires and injectors themself?
I dont have the wiring diagrams if anybody could assist me with a copy
Looks like he repaired the blown resistor and sent it back..
My biggest question is how can I locate the short? Can it be a component somewhere thats shorting? Since its the injector driver resistor blowing does that mean look only at the injector wires and injectors themself?
I dont have the wiring diagrams if anybody could assist me with a copy
Last edited by Merc007; 06-25-2020 at 11:35 AM.
#17
Have you done any searches?
I find the XF electrical diagrams here;
XF Electrical Diagrams
Might be worth a download and look?
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I find the XF electrical diagrams here;
XF Electrical Diagrams
Might be worth a download and look?
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