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Jared D
Jared D, ASE Certified Technician
Category: Toyota
Satisfied Customers: 1863
Experience:  Shop Supervisor at County Fleet
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2005 prius with 80K miles - has codes c1259, c1310 and c1378

Customer Question

2005 prius with 80K miles - has codes c1259, c1310 and c1378 - the car will not start - the light on the power switch stays orange - the hybrid battery and aux battery are new
JA: Just to clarify, what are the exact lights you're talking about?
Customer: red triangle and the brake lites and the orange lite on the power button showing that the car is not ready
JA: Are you fixing your Prius yourself? What have you tried so far?
Customer: yes - I will be fixing for a friend so I don't have the car yet - have not found much on google
JA: Anything else you want the mechanic to know before I connect you?
Customer: nope
Submitted: 11 months ago.
Category: Toyota
Expert:  Jared D replied 11 months ago.


The codes you list indicate a major problem with the hybrid battery pack. The usually mean the battery needs to be replaced. They could also indicate a bad hybrid ECU. How much diagnosis/repair do you plan to do yourself?

Expert:  Jared D replied 11 months ago.

Do you have access to a Techstream totoya scan tool?

Customer: replied 11 months ago.
the hybrid pack was rebuilt and an additional pack from another vehicle was tried as well - same codes with both - I do not have a tech stream - do u know how I could get one - here is a link the the exact same prob n another prius -
Customer: replied 11 months ago.
I have read online that c1259 and c1310 can both be set when the car is n a no start condition which it is - the only code left is c1378 which is discribed here: think there is prob a simpler solution as this car had no issues before the batteries were replaced and runs great when I get is started
Expert:  Jared D replied 11 months ago.

A Techstream is about $2000 used and will likely not have the latest Toyota updates since they are around $1000 per year as well.

Some of the functions can be performed with a Snap on Solus or equivalent but you won't be able to do everything a Techstream will.

The C1259 and C1310 usually only set with a communication fault between the regen braking module and the HV battery. So when you read that c1259 and c1310 set whenever there is a no start condition that is probably backwards. The no start condition is likely a communication problem with one or more other modules, which in turn sets the c1259 and c1310.

The C1378 indicates a voltage supply problem to the brake control system.

The brake control power supply is in the right side of the trunk by the 12 volt battery. At the brake control power supply connector B18 pin 8 Blue(L) wire, check for 12 volt battery voltage.

At B18 pin 5 Black wire, check for 12 volts with the ready light on.

Check B18 pin 14 White/Black wire for ground.

Verify that at B18 pin 12, a Black wire and pin 13 Pink wire, there is a 12 volt square waveform when the ready light is on.

Expert:  Jared D replied 11 months ago.

I think you will find a voltage supply issue, a bad connector, or a blown fuse somewhere. It's just a matter of finding where it is.

Customer: replied 11 months ago.
can u send me a picture of the connector with the pins labeled so I can check the above pins - also do I check with the connector unpluged or still plugged in from the back side - I have a 12v probe and understand the diff between a test light and a probe - thanks so much - peace, peter
Expert:  Jared D replied 11 months ago.

This diagram shows how to run the test:

Customer: replied 11 months ago.
apparently these were not the codes because they r not coming back - I am not getting any codes - just goes to problem on display and the red triangle and the brake light with ! in center - it will not go into ready mode and it is not setting any codes
Customer: replied 11 months ago.
here is an identical problem - let me know how to proceed - there r no codes stored
Expert:  Jared D replied 11 months ago.

I'm confused about where we sit on this. The gas engine won't start and the electric motors won't run, but there are no trouble codes? The post you attached about the identical problem lists several trouble codes and a number of battery checks and disconnects performed by the owner. You don't have any trouble codes and have yet to check the individual cells of the HV battery right?

Customer: replied 11 months ago.
the hybrid battery is rebuilt - the aux batt is new - there r no codes and the car can only b started by disconnecting the battery for a couple minutes and then it will start once, but not after u shut it off - please read the chat I sent u as it has all the details
Expert:  Jared D replied 11 months ago.

You are telling me that you are having the exact same problem as the people in the forum links you keep sending me. They have trouble codes- you do not. They have attempted multiple checks on the hybrid battery- you have not. It seems to me that the problem you have has only slight similarities to the chat you sent in that it won't start.

Your question has dropped to my timed out list.