Dash Warning lights - how to test?

Hello to All,

First Post. I recently purchased a 2008 Prius base model. The car starts and drives fine. The 12v battery remains at 14v even with the headlights on. The Cruise Control engages and holds the set speed.

Howver, the READY light has never illuminated, nor has the CRUISE indicator ever lit when the cruise control is engaged.

The speedometer/odometer/trip and gear indications work fine - the board/display providing those functions was said to have been replaced previously.

Turn signal, parking brake, and door open indications all work.

So I appear to have some problem with at least some of the warning illuminators to the right of the speedometer module. I do see the Headlight indications, and I have a occasional MIL light which I have traced to a coolant control valve, which I intend to replace shortly.

I think I recall reading that ALL warning lights are illuminated briefly during the transition to READY, but I do not observe that on this vehicle.

Has anyone experienced these symptoms and resolved the issue?
Is there any way to force illumination of all of the Warning indicators to verify the lamps/leds/etc. themselves?

I am concerned that some critical warnings such as low oil pressure may not be functional.

Blake in Arizona

 

Good Morning to All,

Thanks for the replies. None of my warnings illuminate in IG-ON. I am told the Combination Meter has been replaced on this vehicle. That makes me wonder if perhaps a connection to Warning Panel was disturbed during that process. I can see the headlight and MIL indications (although not at when transitioning to IGN ON), so the panel has at least some function.

I will try to acquire Techstream/cable. Seems to be several options - if there is any updated HW/SW to simplify installation on Windows 10, I would appreciate a pointer. I do have some old Win7/8 computers that I can use if necessary.

I suspect the Determination/Detection circuits are working - If the Prius was not actually in READY, I'm sure it would not start - All posts I have searched for no READY indication state the the vehicle will not start. So my current theory is a bad warning board and/or faulty connections to this board (I am assuming it is a circuit board, but I don't know).

I watched several videos of Combination Meter Replacement, hoping to get a glimpse of the Warning indicator board, which is just to the right of the CM and closer to the driver. However, I was not able to get a good look. I also searched Toyota parts diagrams to find same, but was unsuccessful. Any pointers to that information or P/Ns would also be appreciated.

I understand the cautions about Oil Pressure. I checked the Oil level in the car at purchase - It is clean and full. I do not rely solely on warning lights to make sure a car is healthy.

The car is drivable as is, but everything else on the car is working, and these issues will continue to bug me until resolved.

Thanks again,
Blake in Arizona

 

Thanks for the reminder about 12v battery check. With everything off it shows 12.6, drops to 12.2 with headlights on. I think that should be good enough?

I read the entire thread on the CM, but still don’t understand if it drives the warning/info lights to the right of the fuel gauge (ABS,VSC, etc.), and if there is a separate electrical connection that drives these. I would like to have a better idea before tearing apart the dash (the CM thread does have pretty good info on how to do that.

Thanks to all,
Blake in AZ

 

Adding more information discovered at another Prius sight.

The warning light panels to the left and right of the combination meter appear to be driven by the combination meter itself. Reviewing the CM thread here, these ribbon cables are clearly shown (and in fact detached/reattached during CM repair). So it now appears obvious in retrospect that the ribbon cables attach the CM to the back of the Warning modules, which contain LEDs. Since LEDs are quite reliable, I suspect a bad ribbon cable or cable connection. Another possibility might be a bad CM itself, but all the indications on the CM Itself are fine, so I’m thinking CM is OK.

Maybe the CM repairman just failed to seat the ribbon cable properly…

I think I have enough info to justify tearing apart the dash when I get the time to do so.

Thanks for all the help.

Blake in AZ