inverter coolant pump + abs codes

Discussion in 'Generation 1 Prius Discussion' started by KarenA, Aug 2, 2018.

  1. KarenA

    KarenA Junior Member

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    Hi there!

    My 2003 Prius has thrown codes P3130 and P3125, which thanks to the great threads posted here I'm thinking is a problem with the inverter coolant pump. Coolant levels were at minimum, no turbulence in the reservoir, some small bubbles, The car starts fine, the battery and charging system seemed fine, but it doesn't seem to accelerate well -- the pedal is mushy when depressed. I virtually coasted it home for about 1/2 mile very slowly with everything off after the first sign of trouble (the dreaded triangle).

    I went back to the car see if I could get my Innova 3040c scanner to show me the 3-digit info codes. This time I saw the ABS warning light flashing and checked those out. Zounds! C1271-4 (Low output voltage of all four speed sensors); C1275-8 (abnormal charge in output signal of all speed sensors); C1281-4 (various pressure sensor, vacuum sensor, and position switch problems).

    I'm wondering whether my 20-second diagnostic tests of the charging system, when I had the car running up to 2000 rpms, was enough to cause heat damage. (Will kick myself forever if this is the case, but tell it to me straight anyway and maybe someone else will have fair warning). With 150K on my 2003, I'll probably have to get rid of this sweet little car if it's much more than a few hundred dollars to fix.

    Any ideas will be much appreciated :)
     
  2. Brian in Tucson

    Brian in Tucson Active Member

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    No turbulence in the reservoir it the clue. You need a new pump. You can get one at A mazon for $135. If you can do your own work, it's not a terrible job, hardest part is getting the hoses disconnected. If you can't, probably a couple of hundred in labor. Doesn't require any special tools.
     
  3. KarenA

    KarenA Junior Member

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    Thanks, I'm assuming that I need at least a new pump. It's the ABS codes that made me worried that I had done secondary damage.

    I found this guide on diagnosing and changing inverter pumps for the Gen I and Gen II Priuses that looks helpful. Can't vouch for it personally. It says:

    Sometimes there will also be a P3125, INF Code 264 – DC/DC converter malfunction, and a bunch
    of low-voltage-related codes in the ABS/VSC ECU, Transmission Control ECU, etc. Ignore these codes
    for now. When the inverter overheats, the DC/DC converter (part of the inverter) will stop working.
    The DC/DC converter charges the 12V battery, like a generator on a standard car, so your customer may
    report dimming lights, the Multi Function Display (MFD) screen flickering, or similar “alternator-like”
    symptoms. The car may even stall and require a tow. The DC/DC converter will probably work OK
    once the auxiliary battery is charged and the inverter cooling system problem has been corrected.​

    It would be good to know how quickly I can damage the inverter or what might stop working when the inverter pump isn't working. I'd hate to tow the car to a dealer only to have to tow it to a junk yard. (I could do the work if I had the space. The instructions say to remove the inverter drain pump in the transaxle, and I'd be doing that on the street. If I could just replace the pump cleanly and tow it to the dealer for a refill, that would be ideal.)
     
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  4. Brian in Tucson

    Brian in Tucson Active Member

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    Hard to know what your situation and capabilities are. I suspect that if you live on a neighborhood street as opposed to a busy thoroughfare that you could get by working in the street. I would say that you could drive it to a shop for the repair--a general mechanic shop could do the work. Or a Toyota dealer. Or an Indie hybrid shop. With all the taxis that are now Prius's, there's probably at least one available. The NY version of Luscious Garage maybe? The inverter takes care of itself, overheating it isn't good, but usually it shuts things down before it can burn up.

    When mine started to fail, it stopped running in Klamath Falls OR. Cooled down and then started. With all the annoying lights. I drove it on to Reno and parked it for the night. Next morning it started just fine and the lights had gone out, so I drove it home to Tucson. We're talking almost 1000 with a weak/bad pump! Lights came back at home and I replaced the pump. I think if you went out this morning, all the warning lights might have gone out.

    Replacing the pump requires removing the driver's side head light, which requires undoing the the front fascia/bumper on that side. Then it's a tight fit with your hands to get in and replace the pump. Nice if you have backup, you might need to take a run to the autoparts store to get some coolant hose. Often, not enough coolant is lost to make any difference, bleeding that system isn't necessary quite often. Use the correct coolant, tho. Don't use the green stuff. If it's all that's available, Prestone Dexxcool will suffice. Or VW coolant (which is the proper color.) If there's a Toyota or Indie toyota/prius shop around, buy your coolant from them.
     
  5. Brian in Tucson

    Brian in Tucson Active Member

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    The pump isn't in the transaxle. There is a drain plug that's inbetween the transaxle and the motor. Don't drain the system! Or the transaxle!
     
  6. ChapmanF

    ChapmanF Senior Member

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    Ok, that would be a weird thing for the instructions to say, as Brian noticed:

    So I went and read the guide. Seems like a simple typo ... the guide said to remove the inverter drain plug (not pump) in the transaxle.

    I think Brian's advocating to just use a couple hose-clamp pliers and clamp off the hoses before removing the pump, losing as little coolant as possible, then just top up again after changing the pump.

    If for any reason you do want to drain the inverter coolant, you should be aware that there are two drain plugs down there, and they are both the same size and shape in Gen 1, and one will drain the coolant (yay!) and the other will drain the transaxle oil (boo!). So you'll want to be sure which is which. (To make matters worse, both fluids are red, though of course you can tell the difference because the coolant is red and watery, and the oil is red and oily.)

    In Gen 1, the oil drain plug is located in a black steel pan at the bottom of the transaxle. The coolant drain plug is located right in the aluminum housing of the transaxle itself.

    Whether you drain it, or just let in a small amount of air at the pump hoses, there is an air-bleeding procedure that is a little bit fiddly for Gen 1.

    -Chap
     
  7. KarenA

    KarenA Junior Member

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    This all sounds great -- I can clamp off the hoses and not worry about draining the coolant. It also sounds like this is a purely mechanical job -- I've been reluctant to mess with the hybrid engine even for simple issues. Thanks for clarifying this.

    Yes, that was a typo -- I meant plug, not pump.

    Also good to know that I most likely didn't fry the inverter.

    A local dealer told me that changing the pump would be a 6-hour job. This seems way out of range of what folks are saying here, so I'd just as well do this myself. Though it seems like a good idea to take it somewhere afterwards to replace the coolant as part of the 150K mile maintainance.

    Do you have any recommendations for the replacement pump? It's $170 from the dealer, and I understand that it's been redesigned for the Gen I. I like to go with quality parts, but if it wouldn't make a difference, I'd get an OEM equivalent and save some money.

    I love Luscious Garage, which is where I took my car when I was in SF. But then I moved cross-country and independent hybrid shops are few and far between.
     
  8. Brian in Tucson

    Brian in Tucson Active Member

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    The oem pump is available from Am azon for $135.
     
  9. mroberds

    mroberds Member

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    The dealer may be quoting you the full "book time" for all the steps of the operation, including replace and remove bumper cover, R&R headlight, R&R pump. You definitely need to R&R the headlight and pump, but you might be able to "cheat" a little on the bumper cover.

    The first time I tried to replace the inverter coolant on my '01, I was having trouble getting the air bled out of the system, and I took out the headlight with intentions of fooling with the coolant pump. If I remember right, I didn't have to take the entire front bumper cover off; I took out the fasteners starting at the right front wheel well and working forwards and to the left; by the time I got to the middle of the car, the outside end of the bumper cover was sagging down enough under the headlight that I could get a socket on the lower headlight bolt. (I ended up not doing anything with the pump at that time, other than admiring it.)

    The only other advice I have on this job is that after ~15 years, the plastic tabs on the top of the headlight assembly that are bolted to the upper radiator support (body-color piece of metal) may be a little brittle. I took the bolt out of one of mine but the plastic tab stayed stuck to the metal, and when I tried to pry it up, I put a crack in the tab, from the bolt hole rearward. I didn't have to replace the headlight because of this, but I figure you should know. If you have a choice of unbolting these tabs when it's warm (like, under a dark-green hood in the sun all afternoon) and with something wider than a regular screwdriver (like a putty knife with masking tape on it, or a plastic drywall knife, or maybe even something like an old expired credit card or gift card), do that.

    If you look around a little, a few dealers will discount parts online. One near me sells the pump for $127, plus an estimated $19 shipping to 10101 (NYC). Since the dealer is just across town, I have figured out that it works to order and pay online, and put "do not ship - will call" in the online order instructions. I then walk into their parts desk a few days later and get my stuff. (If I just walk up to the parts desk and buy something, without having already ordered it online, they charge list price. Very strange.)

    I hope this helps!
     
  10. KarenA

    KarenA Junior Member

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    Update: The new inverter coolant pump is working great. Here's what I learned as a newbie, all to be taken with a grain of rock salt:

    1) I should have disconnected the negative terminal of my 12v battery (10mm socket). By the time I finished the job, the already-old battery had to be replaced.

    2) I shouldn't have let the car sit for so long (weeks) without being driven. Once I got it working again, I got a P3009 HV voltage leak code that I had never seen before. (Still sorting that out). That was when I saw all the warnings about how the HV battery can be damaged by inactivity.

    3) replacing the inverter pump is very doable if you know what you're doing.

    4) all the advice that I saw said to use a 24mm socket to remove the coolant drain plug. It had too much play on mine. What finally worked was a 15/16" 6-sided mid-depth socket. I only found one for a 1/2" drive. Advanced Auto, PepBoys, and probably other stores rent free 1/2" torque wrenches. I also used penetrating oil to loosen the plug. Someone suggested using a breaker bar, but that didn't seem prudent.

    5) It seemed worth it to get a new gasket for the drain plug, that I used only when I put the plug back at the end of the job. One retailer told me to use anti-seize grease on the plug and another told me not too. I followed the latter's advice.

    6) There's a lot of talk about removing the front bumper. All I had to do was remove the two 10mm bolts and the one center push plug on the top (which is right next to the hood latch). Raising that top piece gave me the room I needed to remove or replace the headlamp assembly. The driver's headlamp assembly had 3 connections (2 that rotate and 1 plug that gets pulled out). It also has 2 (IIRC) 10mm gray bolts. I broke that center push pin for the bumper when I removed it, so I got a new one with the gasket.

    7) It was better to drain the coolant rather than try to clamp off the hoses. More than 1/2 gallon of coolant drained into a shallow laundry pan. While I was having trouble with the drain plug, I tried my Plan B -- plastic hose pinch-off pliers instead. But once the pliers were in place, I didn't have room to access the hose clamps on the pump. It would have also been a mess, I think.

    8) The pump is bolted with two 10mm sockets and has a connector that pushes out. Even though I had drained the coolant, I used the hose pinch-off pliers to minimize any spillage. The band hose clamps were difficult to get off. What worked for me were WD-40 and long-reach angled needle-nose pliers (much cheaper and more versatile than the hose clamp removal tool). I caught what little spillage there was when I got the hoses off with a little plastic cup. Putting the hose clamps back in the same indentations on the hose sounded like good advice.

    9) Make sure to have the drain plug + new gasket properly torqued before refilling the coolant. I also made sure that the nipples would be easy to unscrew before filling the hoses with new coolant. A 10mm socket wrench was all I needed, but if it's tough, I was told to hold the stem with a 14mm crescent wrench. Bleeding is very easy; no bleeding tube is necessary. I just filled the reservoir to the top. loosened both nipples and closed them as soon as coolant started to come out. Topped off the reservoir again. Started the car and topped off as it ran. Repeated a couple of times. I also heard that temperature changes while letting the coolant sit overnight makes the bleeding easier. It seemed to work. Just keep a close eye on the coolant level for the next few trips.

    10) As I was figuring out how to do this, I saw lots of people writing that the pump is so likely to go bad that it should be replaced preventatively. That seems like a good idea in retrospect. Mine went at 150K miles. I got my genuine Toyota part from a dealer on Amazon.

    Hope this helps someone, and good luck!
     
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