"I always unplug the OBD reader". Your test is with the OBD connected? as that's what I'm referencing. I didn't however check after 30 minutes, I just left the OBD connected whilst the ignition was off and car locked.
Emira JB4 Tuning Now Available for I4 & V6 Cars!
- Thread starter GRP
- Start date
@virtualmacho according to gpt:
JB4 users report:
JB4 users report:
- Increased parasitic draw via OBD
- Alarms / comfort access / wake-ups overnight
- Issues appearing once the battery is a few years old
- Problems disappearing when:
- JB4 is unplugged or
- Battery is replaced and/or
- JB4 OBD power is switched off or interrupted
I have an OBD split cable with one branch always connected to the JB4. My bluetooth OBD dongle on the other branch is always unplugged unless I am logging data because I know there is parasitic draw as the LED indicator is lit.
My JB4 unit is always connected to the OBD port, and I cannot connect to it from tha app a few minutes after leaving the car and locking the door.
Interesting, so not just the JB4 plugged in.. it's routed which might auto-turn-off. let me check
You are right. I failed to connect to the Bluetooth after 4 minutes.
However the board might still be live for the OBD. Which could mean there is slight parasitic drain. That in conjunction with a 3+ year battery could be the issue I’m facing.
I have a new battery I might just throw it in…
Yes, I'd do the same. You're going to need to replace the battery anyway.
What a PITA.
If only someone would come up with a real solution so your car behaves exactly like OEM just with more power.
Until then, I’m out.
This is not with everyone. I left my car under a cover in cold NY for over a month several times and it started right up no hesitation. Jb4 connected and all. Its not the JB4. His car has some other issue.
In the case of the AMG powered unit. Would it help cooling by removing the engine cover to allow the fresh air to escape easily through the glass factory. Or, does the cover provide better transition/direction of airflow in the engine bay?
Thanks for your thoughts on this query.
Hi everyone,
I wanted to ask if anyone here is running a JB4 tune on the Lotus Emira V6 Automatic (IPS/DCT) and what your experience has been so far.
I installed JB4 recently, and after only the second drive, my gearbox suddenly developed a serious issue — one solenoid completely stopped working, which caused the car to lose forward gears. Reverse still worked, but the transmission basically failed.
What makes this even more concerning is that the car has only around 2,000 km mileage, so it’s basically still new.
In the end, I had to replace the entire gearbox with a new unit, which was obviously a huge and unexpected repair.
So I’m wondering:
I’d really appreciate hearing from others, because I don’t want to risk damaging the new gearbox.
Thanks in advance!
I wanted to ask if anyone here is running a JB4 tune on the Lotus Emira V6 Automatic (IPS/DCT) and what your experience has been so far.
I installed JB4 recently, and after only the second drive, my gearbox suddenly developed a serious issue — one solenoid completely stopped working, which caused the car to lose forward gears. Reverse still worked, but the transmission basically failed.
What makes this even more concerning is that the car has only around 2,000 km mileage, so it’s basically still new.
In the end, I had to replace the entire gearbox with a new unit, which was obviously a huge and unexpected repair.
So I’m wondering:
- Is anyone else using JB4 on the V6 auto?
- Have you had any transmission or solenoid-related issues?
- Do you think JB4 could affect gearbox pressure/heat or trigger failures like this?
- Any advice before I consider reinstalling it again?
I’d really appreciate hearing from others, because I don’t want to risk damaging the new gearbox.
Thanks in advance!
I’ve put about 5000 mi on the JB4 in my V6 auto with no issues.
So sorry to hear of your situation. I believe many are concerned about that extra power when unleashed. Associated members have made a good point previously that there will always be extra strain on components, when increasing engine output.
In my case (2.0 T) I am still installing a JB4 but have resolved never to use the car for standing start “drags” (something I am loath to do with any vehicle). Even on a standard vehicle, the initial force exerted, plays on my mind. Rolling starts (50 km/30 mph), I personally have no qualms about.
Were you engaging in an inordinate number of “standing start drags” prior to the severe damage occurring? If so, perhaps this may be something to consider.
Thanks for your message — totally understand the point about additional strain when increasing engine output.
In my case, during the first ~1500 km I was actually very careful and tried not to exceed 4,000 rpm at all. That said, this is still a sports car, and giving throttle from a normal intersection start seems completely reasonable. The car had only done around 2,000 km in total.
Right after installing the JB4 and driving just a short distance, I started to notice a strange feeling — almost like the gearbox was “tightening up” or hesitating, not shifting properly or on time.
After roughly 10 km, the car suddenly stopped moving forward completely. Only reverse gear was still working.
The worst part is that Lotus refused to cover it under warranty because the JB4 was installed. The gearbox cannot be removed without taking the engine out, so the repair became extremely expensive. The total cost was around €20,000 (about $24,000 USD).
I contacted the JB4 team, sent them the details, and explained that Lotus specifically blamed the device — but their response was essentially that they cannot help and that it is my problem.
So unfortunately, in my experience, the issue appeared immediately after installing JB4, and the consequences were very serious.
In my case, during the first ~1500 km I was actually very careful and tried not to exceed 4,000 rpm at all. That said, this is still a sports car, and giving throttle from a normal intersection start seems completely reasonable. The car had only done around 2,000 km in total.
Right after installing the JB4 and driving just a short distance, I started to notice a strange feeling — almost like the gearbox was “tightening up” or hesitating, not shifting properly or on time.
After roughly 10 km, the car suddenly stopped moving forward completely. Only reverse gear was still working.
The worst part is that Lotus refused to cover it under warranty because the JB4 was installed. The gearbox cannot be removed without taking the engine out, so the repair became extremely expensive. The total cost was around €20,000 (about $24,000 USD).
I contacted the JB4 team, sent them the details, and explained that Lotus specifically blamed the device — but their response was essentially that they cannot help and that it is my problem.
So unfortunately, in my experience, the issue appeared immediately after installing JB4, and the consequences were very serious.
unlike the manual trans(which user controls) the Automatic transmission *RELIES ON AND REQUIRES* Accurate information from the ECU side (engine) in order to calculate torque, solenoid pressures, shift timing, etc. The JB4 Spoofs sensitive data and likely the TCM is getting *inaccurate* data, which in turn the TCM calculates wrong pressures, wrong shift timing, wrong torque controls to match engine torque, etc. The loss of your transmission is not surprising. Very unfortunate. Sorry to hear.
That was a nice summary. That's why I'm waiting for yours. We await your dyno results!
Tell Lotus Miami to hurry up and get us our Emira
Ouch! That really is a huge hurt. My condolences.
I guess in the case of JB4 and the AMG (2.0 litre) installed in our Emira’s, the engine comes detuned below what is installed in Mercedes cars e.g. 45s. Knowing that this engine can and does produce the equivalent hp and torque to the 45s Merc, does add confidence to fitting the JB4 to our 2.0 T engines.
Interestingly, a Lotus dealer I know of, is supplying and installing JB4 to the 2.0 T’s. I asked how this would affect any warranty claims…….. the answer: it is easy to remove without trace. My lips are sealed from this point forward.
LOL, no trace............. Did they forget the ECU data logs
Even with my clone ecu, if Lotus really wants to.dig deep, they will find the evidence. This kinda rumor has been going on for so long...
Autosport designs in new york has a 2026 V6 and a turboTell Lotus Miami to hurry up and get us our Emira
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