Toyota Prius Forum : Toyota Prius Forums - View Single Post - Reoccurring EML issues
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post #1 of Old 10-19-2020, 07:52 PM Thread Starter
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Default Reoccurring EML issues

I have a Toyota Prius 2016 4th Generation (new shape).
I noticed the Engine Management Light kept coming on intermittently. Sometimes once a month, once a week or even after every couple of days.
I had it diagnosed it on a normal diagnostic machine from a local garage & the Fault code kept coming back as ignition coil plugs 1,2,3 & 4 (A,B,C & D).
I changed all 4 Ignition Coil plugs & All 4 Spark Plugs all brand new from Toyota original parts.
The EML came back on.
I then took it to straight to Toyota & their diagnostic machine also showed the same faults with the ignition coil plugs but as they had already been changed they recommended I change the cars Auxiliary battery & replace the hybrid battery filters as they were quite dirty - I got the work carried out by them.
The EML was STILL ON when I went to pick the car up from them.
Toyota are now saying that they have exhausted all avenues & they can only suggest itís 1 of 2 things - either the ECU has an issue/needs replacing or the wiring loom leading from the ignition coils to the ECU maybe faulty.
I got a local garage to check the wiring loom to see if there were any signs of any loose connections, cuts or any tampering but there is no sign of this at all, all the wiring looks genuine & clean & untouched/untampered with.
I find it hard to believe that there is an issue with the ECU & there is no way of testing the old ECU, there is no Auto Electrician in the country that will touch it as it is a hybrid & they simply donít have the software to test them. Toyota have also said they cannot test the old ECU & even if I replace the old ECU with a new one they will still not guarantee that this will solve the EML issue.
Please can anyone help me??
Do you have any suggestions ? Have you heard of or come across anything like this before with my particular car? It is really important I get to the root of this problem as I have already spent so much time & money on the car & it has still not sorted this issue out & my vehicle is used as a taxi so it is important for work purposes also.
Look forward to hearing from you.
Many Thanks in advance.
Andy is offline  
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