Engine Starting Problem

My advice is that you perform the necessary maintenance on your Prius so that it will be reliable and you don't have to jump the battery constantly, leave the heater on in an effort to force the engine to run, etc. You should not embark on a winter road trip with a car in such poor condition. This could become very hazardous to your personal safety if the car is stalled in a dangerous area.

1. Replace the 12V battery. Stop messing around with a near-dead battery. The various Prius ECUs require clean power. Who knows what glitches have been introduced by your many efforts to jumpstart and charge the battery (I assume that you have not disconnected the battery cables before charging.) When replacing the battery, allow all ECUs to power down. Do not connect an auxiliary power source in an effort to keep ECU memory alive.

2. Buy a can of throttle body cleaner. Remove the air cleaner assembly and clean off the black gunk in the interior of the throttle body and on the throttle plate. Rotate the spring-loaded shaft to view the underside of the throttle plate. Use the minimum liquid necessary to do the cleaning. When you are done you should see shiny metal parts.

If it is too much effort to remove the air cleaner assembly, make sure that you do not contaminate the mass air flow sensor with the cleaner liquid.

3. Check engine oil viscosity (which should be 5W-30) and fill level (which should not exceed top dimple on dipstick).

4. If you still have problems with the engine failing to start, replace the iridium spark plugs if they have more than 60K miles. Buy the correct NGK or Denso plugs as specified in the owner's manual which should cost ~$50-$60 for four plugs at your Toyota dealer. Look at the engine air filter and replace if you don't see light when you hold the filter up to the sun.

5. If you still have problems, find the engine ECU located behind the glove box and determine the part number. If lower than 89661-47054, buy that part number from a salvage yard, might cost you $300 or so.

6. Check fuel pressure which should be 43 psi at idle speed (assuming you can get the engine to start.) If low, remove the circuit opening relay, apply 12VDC to the coil terminals, and measure resistance across the switched terminals, using a digital multimeter. Replace the relay if resistance is greater than 0.5 ohm. If fuel pressure is still low, replace the fuel tank.

For more info, do a search for TSB EG011-03 which I previously posted.

 

You've posted in the wrong forum. Maybe a moderator can move this to the Gen 1 forum.

 

Lights/dash come on and then the "Main" light flashes

Try to get the engine code(s) read , some auto places eg Autozone will read trouble codes for free; and report back, that should help isolate the cause.

 

You are right, the presence of that icon on the MFD means that the traction battery has died. Maybe this is because the battery was drained after numerous attempts to spin the gasoline engine. The car probably still has the underlying problem that causes the engine to exhibit no-start issues.

How many miles on the odometer?

How much fuel is in the gas tank?

For future reference in case you get that far, the correct iridium spark plug is NGK IFR5A11 or Denso SK16R11.

At this point, you'll probably need to tow the car to your local Toyota dealer for assistance. Note that a new battery will cost ~$3K including labor time. I am assuming that a project to DIY install a replacement salvage battery would not be of interest to you. If I am wrong, do a search on that topic for recent examples of such work.

 

How would i get the codes read/how to get to them?
Order a scangauge from priuschat website, glad I did.
Everyone should have one of these driving a prius, the car is sorely lacking in gauges.
PriusChat Shop : ScanGauge II Scan Tool + Digital Gauges + Trip Computers [ScanGaugeII] - $159.95

There is always next time, and this may help others, understand you are probably in a hurry to get your car fixed.

 

Patrick is right on the money with the ideas like spark plugs, throttle body and new 12v battery. :thumb: My car runs 100% better after new plugs and throttle body cleaning.
One thing I learned painfully (expense + stress) is that the Gen 1 software "protects" the car by not allowing the engine to start when the main traction battery is low. I was able to to charge the traction battery (after I had a fresh 12V batt) by running the engine with the a/c on max, with the factory scan tool plugged into the car watching the battery ecu / live data. The factory scan tool also has a feature to charge the traction battery, but I have never used it, nor know how to use that feature.

Hope that info helps.

I seriously doubt most main traction batteries that are replaced are really all bad. The factory scan tool allows you to monitor every cell in the battey and get a feel for the condition. There is also a comparison between the best and worst cell which is used to determine overall condition. How many Toyota techs know or are willing to share that information?