2001 prius will not start and run , problem/solution

This Roy from Canada -- During a private conversation I asked for help and got it from 3 prongpaul and john britprius. They thought the problem/solution would be helpful to others and should be in the open forum and I agree. This is a copy of some of that conversation

(a) Question

Problem: Started car yesterday in early mornig, car started ok and drove 1/4 mile then triangle came on, drove back home 1/4 mile on battery to my garage.

1) Put on minivic and got P3191,P3101 and P1127.
2) Cleared codes with minivic and started again in park -engine runs 10 seconds and quits.
3) Cleaned throttle throat lubricated butterfly valve - reset codes - engine runs 10 seconds quits in park but will keep running in neutral, hv battery runs down from daylight running lights so had to recharge with my high voltage charger to 60% SOC (as shown by minivic).
4)Added fuel injector cleaner to gas tank and ran engine for 1 hour in neutral.
5) Put car in park engine runs ok until the car starts to charge the hv battery, it will run 10 sec and engine cuts out only when the car starts to charge the hv battery. Codes 3191 and 3101 keep coming up.
6)My computer with minivic died so I can not use it to troubleshoot at this time.
7) If I manually open the throttle I can get it to charge the battery in park a few seconds longer by increasing engine speed of the engine then it will sputter and quit with the triangle coming up.
Note -- I can get the engine to run continuously in neutral with no triangle coming up.


(b) Answer

If engine only "runs" for 8-10 seconds it never actually started, even though it sounded like it did.

First thing is try swapping air cleaner/MAF with known good one from your other gen1

Then remove throttle body completely from car and do a more thorough cleaning, including puddles as bottom of intake manifod, or swapping it with known good throttle body. P3101 and P3191 are usually throttle body related.

Will engine run continuously if you burst starter fluid into throttle body every few seconds?

Are you sure no P3009 error?

Unlikely to have 4 bad fuel injectors but could be bad fuel. (starter fluid will help diagnose) Did anybody fill up with diesel or E85 by accident?


(c) Answer

Hi Paul - the ice is running all I have to do is put the shifter to neutral before the 10 seconds and the ice will keep running. If I shift back to park the car will run until the battery calls for charging then it dies, the car will run for hours in neutral ( I left running for 1 hour after I put the injection cleaner in it)


(d) Answer

Hi Paul - I have changed the throttle body and the CPU and the problem still exists. I have my mini vic working now.
In my service manual It indicates code 1127 is an open in the circuit that is provides a voltage to the engine cpu from a fuse called "THRO". I have checked the fuse and it has continuity. With the mini vic I have noticed that when the display shows the battery charging the minivic shows the battery is not charging in that it has a positive current not a negative current, and the battery keeps running down its "state of charge". The manual indicates a voltage should exist at terminal BM in the connector going to the CPU of 9 to 14 volts - I do not have a voltage on the connector when I disconnect it from the CPU with the key turned on or off. I am going to send you a copy of the service manual - go to page 275 to see the circuitry ---- see what you think.

(e) Answer

Do you get voltage if you backprobe the connector still connected to the ECU? Use a pin with aligator clip if necessary to get a good connection if you don't have backprobe like this Amazon.com: Electronic Specialties 142-5 Flexible Silicon Back Probe Pin: Automotive

If no voltage, something is wrong with the wiring harness.

To confirm faulty harness, temporarily run a jumper from + battery to terminal BM using backprobe method, see if car starts/code goes away.

(f)Answer

I backfed the circuit and the car starts,runs in park and the mini viv now matches the display in that it shows charging and a negative current is shown on the minivic.I cannot take it for a drive yet as I want to find the break in the wire.I have yet to find the where the break is in the harness, I will check each end of the wire at the connection points with my ohmmeter to start. I do not yet Know the routing of that cable


The car is now running OK. I have left some of the conversation out and only provided the points that led to the solution of the problem which was a broken wire feeding power to the engine cpu to operate the throttle motor. This is apparently a rare problem.

I thank threeprongpaul and johnbritprius for their help as I would not have solved the problem without it.

Roy from Canada

 

Hi Chap - no I do not have that manual.How do I get a copy?

Roy

 

Thanks Tom

Roy

Thanks for the help Chap - I have a toyota service manual that I can send to you if you email me at [email protected].

 

Thanks Chap == I did not know there was a volume just for diagrams at Toyota.
Thanks for the information I will pay $15 for 2 days access.

Roy

 

I will send you the manual and you can compare or use both- email me at [email protected]

Roy from Canada