Possible Solution to intermitent not starting
If you have the following symptoms , this might be a fix for you, and save you a packet of money!
1) Car will not start when turning the ignition key, and date/temp readings are ----- on the dash.
Waiting between 3 - 40 min for the temp reading to re-appear, with a beep, indicated the car can start again
Trying to start multiple times and fiddling with starter relays under the hood, on occasion seems to get the car going, but is nothing related to that, it's just co-incidence that it starts afterwards. Unless of course you have a bad starter motor relay or starter motor, but then you won't get the immobilizer effects kicking in.
I have found the fault is related to temperature, and just opening the windows or shielding the dash from heat can work.
You simply have to leave the ignition switch on, and when the temp read re-appears you are good to go.
2) You are driving and:
You hear the locks clicking
Entertainment system and aircon shutdown
Hazards come on
If you switch the ignition off it might not start
This fault can cycle intermittently on and off whilst driving
The fault gets worse over time, and with me being in a hot country South Africa, I noticed on a particularly hot day temps over 34Deg.C the faults completely disapeared.
The dashboard is terminated on the High Speed CAN bus, which seems to talk to other modules like immobilizer, entertainment, zircon etc, and the system goes in to lockdown mode, if communication is disrupted. The main symptom is that the dash no longer receives the outside temp reading, which is quite telling, I have no idea what part of the car sends the temp readings.
The diagnosis approach I used, once it was fairly certain the fault was intermittent, temperature related, and dashboard related, was to strip out the dashboard, remove its rear cover, then connect it back balanced over the rear of the steering wheel.
Just being more exposed to the air temperature, listened the symptoms . Using a can of Freeze use to isolate thermal related dry joints in electronics, spraying different places when the fault appeared, eventually lead to the corner of the MCU chip 64F2638F20 which is in a 128 pin Quad Flat Pack (QFP) format. Pins 37/38 HRxD1/HTxD1 seem to be the culprit, from where the bus emanated. Scanning the chip with a thermal infrared thermometer showed a distinct hotspot on this corner, no bought related to the power to drive the high speed bus. The obvious conclusion is that the thermal cycling of the part had causes a joint on one of these pins to fail intermittently, and a quick spray of freeze in this area, caused the fault to go away after about 15-30 seconds. Possibly because the high speed bus protocol had to re-establish itself.
I had some links but am unable to submit on a first post
So the fix, is to re-solder pins 37/38, which are on the lower RHS as you look at the QFP. They are covered in a conformal coating, which disintegrates with heat, so running the dry soldering iron over the pins, removes the coating, and then with a wetted tip. you can re-flow the two joints. I found i best to work through my iPhone with camera zoom at max, or there was no chance to get this right. Make sure you don't form a solder bridge between the pins.
This process of diagnostics, took several months, and having the can of freeze on hand, made the problem way less severe with a workaround.
I hope this can be useful to some of you, and I realize you may need to get the help of someone handy with a soldering iron and good eye sight. If not your local electronic repair shop, could also be contacted to reflow the joints for you.
I believe repacking the dashboard is in the region of $1,500 and requires specific programming, and transferring the milage back, so not really a weekend swap out. I also found the scrap people only wanting to sell all the other immobilizer components with the dash.