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JagLandyFord, Jaguar Technician
Category: Jaguar
Satisfied Customers: 87
Experience:  ATA Accredited Master Technician . Achieved Jaguar Master Technician in 2002 & 2007
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I have an engine management light come on and temperature

Customer Question

Hi i have an engine management light come on and temperature gauge shoot into the red on my xjr. Last week it was diagnosed by AA as temp sender which i changed but the same problem occurred today.
JA: Tell me a bit more about what's going on so he can help you best.
Customer: I just told you what is going on!
JA: Are you hoping to fix this yourself?
Customer: If possible
JA: Is there anything else the Jaguar Mechanic should be aware of about your Jaguar?
Customer: Nope except it is supercharged but not relevant to the problem i think
JA: Our top Jaguar Mechanic is ready to take your case. Just pay the $5 fully refundable deposit and I'll fill the Jaguar Mechanic in on everything we've discussed. You can go back and forth with the Jaguar Mechanic until you're 100% satisfied. We guarantee it.
Submitted: 1 year ago.
Category: Jaguar
Expert:  JagLandyFord replied 1 year ago.

Hi There,

If the Temperature gauge is going into the RED, and you have replaced the sensor - then this could be caused because the Instrument Pack Module (IPC) is not receiving the message from the Engine Control Module (ECM).

The temperature sensor sends its info to the ECM via hard wire.

The ECM then transmits this information on the communication wires (Corporate Area Network - CAN), to the IPC.

This leaves a number of potential causes:

  1. The hard wires from the Temp sensor to the ECM may have an intermittent break causing an open circuit - and therefore no info being sent to the ECM.
  2. The ECM has an intermittent internal fault.
  3. The ECM has a poor connection at the pins where the info is received back from the sensor or sent out on the CAN communication wires.
  4. There is an intermittent open circuit wiring concern between the ECM and the IPC on the CAN communication wires.
  5. There is a poor connection at the pins of the IPC for the CAN communications.
  6. The IPC has an internal fault.

To help determine this more clearly a fault code scan of the vehicle would be beneficial.

This would tell us:

  1. a code in the IPC is not receiving the info from the ECM
  2. or the ECM has a fault code stating it is unable to communicate with the IPC.
  3. or the ECM is not receiving the information from the temperature sensor.

If a code scan is not possible - then this would make the job slightly harder as continuity tests would need to be made between the ECM and the temperature sensor, the ECM and the IPC on the CAN wires.

CAN voltage checks, CAN resistance checks.

So for the moment the above information is a guide of the diagnostic route that could be taken.

I hope my advice has helped you understand the concern more clearly if not resolve it outright just yet.

Please 'Accept' my answer if this assists you to resolving your concern - this is the only way I will receive payment.

If the answer is not satisfactory - then please return for further assistance.

Please note - I may not be able to answer straight away myself - as I work full time during a normal working week. - However there will be other experts who will assist you further if this is the case.

Best Regards

Customer: replied 1 year ago.
Thanks for that. I will look at the wiring and connector from the new coolant temp sensor and see if looks faulty. If i can't see anything then it will need to go to a Jag specialist garage for a more thorough test.
Expert:  JagLandyFord replied 1 year ago.


You are very welcome.

Best Regards