Warning light, 10 codes, any thoughts?

One possibility that can cause multiple random codes (and not be too expensive) is a weak 12v battery. Check the 12v battery voltage when the car is off and again in ACC mode. If it is below 12v, that may be the cause.

JeffD

 

the last three are strictly from someone trying to start the car without the smartkey (or without the car detecting smartkey). these are "communication stop" codes. these are called soft codes- they will set a dtc in memory but will not light any kind of light because, well, they're insignificant.

the 1421 is also a soft code. that was a solar sensor circuit.

this sounds very, very much like a 12v electrical system issue. a lot of electrical stuff, a low voltage concern, wiring, etc. first things first, replace the 12v battery. monitor voltage output to the 12v with a meter on the battery terminals.

instead of going through all those diagnostics, get a new 12v and have them clear the codes.

 

C2318 "Low Voltage Error" is reported by the transmission control ECU and triggers when the available voltage drops to 9.3V or less for more than one second. It would be very reasonable to first suspect the 12V auxiliary battery, especially if the battery is original equipment.

If the battery is not the problem, P0A93 "Inverter Cooling System Performance" might point to an overheated inverter assembly resulting in a failed DC to DC converter. Hence the 12V bus voltage would fall below the normal 13.8V, again causing the other DTCs.

 

During much of last year, my car had a whole litany of codes set
across various ECUs that came from playing around and having
various parts disconnected at times. I didn't clear them --
I left them there as a good exercise for the tech-training effort,
telling the students to go pull all the codes and then I could
explain every one of them and even recreate a few.
.
But in a total unknown situation, where stored codes could
reflect unrelated stuff that happened months ago, f'geddaboudit.
SOP is to record and then clear the codes, go for a test drive,
and see what returns to indicate any CURRENT problems.
.
Stored codes also gradually disappear, as there's logic to remove
them if the original problem doesn't recur in something around
40 "trips". Note that the MIL isn't on that whole time, as there
is different logic to clear *that* after only 4 reboots if a
problem cause isn't found. History codes just sort of hang out.
.
_H*

 

Hi Hobbit,

I'm assuming the OP was not experimenting with the vehicle as you do.

Suppose the tech spends 15 minutes retrieving codes and drives around 30-45 minutes. No warning lights come on. Then the service writer explains to the customer that s/he is being charged for one hour of diagnostic time but the car is NTF...

If the customer is expecting warranty coverage for the repair, I suppose s/he then has to wait for another episode of warning lights before any action will be taken?

In this particular case the problem seems to be 12V bus-related given the low-voltage DTC. I've seen instances where posters related that the 12V battery was suspected, tested, found to be good, and restored to service. Then a few days or weeks later the problem reappeared and the battery had to be replaced, solving the problem. What would cause this - an intermittent short in a cell?

If this particular situation happened to me I would be inclined to purchase & install a new 12V battery.

 

more realistically the tech spends 10 minutes waiting for a scantool, 2 minutes clearing codes, and takes the car on his usual test drive loop. unless he cuts a corner and just starts the car and lets it run. but chances are he will not be paid for his time if there is no repair to do so he does end up getting the short end of the stick.

if no codes come back, yes.

 

Hi Galaxee,

I could see that this would really upset the tech, especially if the customer was charged but the tech doesn't get his/her cut.

 

fairly standard operating procedure, really.
diag techs don't make it long in the field before they leave for something that pays more than minimum wage.

 

Thanks. I've noticed the occasional post about a difficult intermittent problem (ranging from HID headlights to sudden unexplained acceleration) and lack of support from the dealership. Your comments help explain why intermittent problems are not welcome there.

Hence the customer must live with the problem until it becomes obvious and demonstrable.

 

well... i've made a couple posts on diagnostics and such, and what it comes down to is that it's pretty tough to sort out some of the intermittent or small issues. mentally a fun challenge, but does not put food on the table, that's for sure.

a lot of the time, if the problem is not present right in front of the tech, there is no way to diagnose it. so they send it back out rather than sit around tapping their foot waiting for the problem to recur. that's called a cnr or could not replicate. no sense standing around doing nothing (getting paid nothing) when one can be earning a paycheck with all the other work that's waiting to be done.

the system is all wrong, but it's not going to change.

 

Changing the temp sensor was the appropriate response to DTC P1116. The alternative would be that the engine coolant system is clogged.

Which cooling pump was replaced: the inverter coolant pump or the engine coolant pump? If it is not obvious when you look at the service invoice, please let us know the part number. Given the DTC P0A93 that you provided I would expect the inverter cooling pump to be replaced.

If you have a digital voltmeter, I suggest measuring the voltage either across the 12V battery terminals; or (perhaps easier) at the positive jump start terminal located in the main relay/fuse box near the inverter, to a bare metal ground. See what the voltage is when the car has been IG-OFF 10 minutes or more. If it is below 12.4V, the battery is getting marginal or needs to be recharged. You would expect to see 12.6V or better if the battery is strong.

Then see what the voltage is when the car is READY. It should be ~13.8V and hold steady, showing that the DC to DC converter is working. Try turning on the headlights, ventilation fan to max speed, rear hatch defroster on, and set the cabin air temperature high (to turn on the PTC electric heaters and maximize electrical load.) The 13.8V reading should hold steady.

The nice long drive, as you mentioned above, should be a good test as well. Good luck, hope that your car is restored to full health.

 

Thanks, here is the part description per Champion Toyota Gulf Freeway's parts website:

Cooling - Radiator and components - Motor assy - W/pump
W/pump - Inverter 2004 - 2008

MSRP: $110.63, their price $84.08

Hence this pump is for the inverter and transaxle coolant loop, which corresponds to your DTC. Hope that this solves your problem.