Error code 1554 - help please!

Interesting, welcome to the club!

Which one? I was looking the completed sales and didn't see one with that code.

Now a code usually has "P" or "C" prefix. Regardless, the most common power steering problem are 'dirty' torque sensors. As a work-around, you can pull the fuses that feed the power steering ECU. But you will have a "PS" error and with the code and error display, it may be difficult to pass any vehicle inspection.

I would recommend:

• Prius maintenance manuals - used ones come available on Ebay from time to time: Volume I - diagnosis; Volume II - repairs and; electrical diagrams to find signals and pins. A new set will cost ~$300 or you can try the subscription, TIS service (Google it up.) Warning, do not get suckered by the "CD" manuals . . . junk and likely copyright violation.
• Scanner - a ScanGauge (see thread) can handle the hybrid vehicle and battery codes (see the thread.) I rent a Graham miniscanner that also provides engine codes but some of them will come from the scangauge, default emissions report. There are more capable scanners starting at $400 to $1,200-1,500 plus your laptop with a USB interface. Standard, over the counter scanners are inadequate.

Anyway, let us know more details and welcome to the club. There is a lot to learn about the Prius and folks where are pretty easy about sharing our 'lessons learned.'

One last question, is this going to be your primary ride or do you have a backup? What sort of cars have you been used to? The reason is driving a Prius like an ordinary car is OK but learning out to drive efficiently pays great dividends.

Bob Wilson

 

David, Bob Wilson knows his stuff on Prius classics.

Can you confirm whether your car is a Japanese only import Prius (1997-2001) or the gen 1 2001-2003 model which was sold to both the USA and Europe. An easy way to tell would be the rear number plate - is it long or square? Long = European car and square is likely to be an import.

 

You'd have to ask the seller if that was the case, why s/he didn't fix the fault so that this would not have to be listed as an issue.

You didn't answer the previous question about whether the car is the newer NHW11 model that was available for export, or the older NHW10 Japan domestic market model. (One clue to differentiate NHW10 is that it lacks the trunk-mounted spoiler and of course, all instrumentation is in Japanese.)

If the latter, and there is any way for you to void the purchase agreement, you should do so and run away as fast as you can. NHW10 is not a practical car to own since repair documentation, diagnostics and parts are essentially non-existent outside Japan.

 

Thanks for the link, it appears that this is an NHW11. Regarding the DTC that the car logged, I no longer own the Toyota repair manuals for this model.

If you don't receive other advice that will help to pin down the problem, you may wish to subscribe to the Toyota Europe techinfo site so that you can download repair manual info: Toyota Service Information Good luck with your purchase.

 

Hi David,

Given the caveat, "Buyer beware," I think you potentially have a good car. It would be nice if you could take a drive in it and I'll try to list things below. The link to the car is fine and the code makes sense:

C1554/54 - EMPS (Electric Motor Power Steering) Relay Circuit

The trouble areas:

• EMPS ECU (unlikely)
• EMPS relay (likely)
• EMPS relay circuit (unlikely)
• hide noisy torque sensors (possible)

So first, let's look at the fuse boxes. When you open the bonnet, there is a notch shaped fuse box on the left (Engine Room R/B No. 3) that holds the EMPS relay:

The relay of interest is identified in the above cover, lower right hand side. Notice the "HTR3 Relay" just above it . . . identical specifications. Hummmmm, yes?

So looking down at the fuses and relays:

The big hummer relay at the lower left is the main EPS power relay. His buddy to the right is the identical, electrical, HTR3 relay, an electric heater element in the dash. So let's see, heat or power steering . . . hummmmm.

You notice there are two heavy duty fuses in the upper left. The second one from the left is the fuse for the relay. This would probably be the least expensive fix. The fuse to the left, the upper left, is HTR3's fuse . . . power steering or electric heater . . . hummmm.

Now inside the cabin is a fuse box in the USA models located to the left of the driver's left knee. I don't know where it is in the UK cabin. Regardless, there is a column of small fuses and the right-hand side the third one down, 7.5A ECU-B, provides power to the ECU.

Now all we are doing is identify the likely parts that may have caused the C1554. But the more important question is "Why these?"

The NHW11 model (2001-03) Prius are known to have a weakness in the steering assembly, the torque sensors. They get 'noisy' which causes the power steering to vibrate or oscillate. The permanent cure is to replace the steering assembly which is easily $1,200 (estimated.) One could get a salvage steering assembly but that has risks too . . . especially where there may not be a lot of choices.

Now you have a decision which I can and others can outline but you have to decide which direction to go:

1. Hack-it :: we can freeze the EMPS interfaces so the PS light and error codes are gone but the car is always in manual steering mode. But this is a sophisticated, new technique and though we can describe the general parameters, you have to look at your own skills and resources (including clever friends) if you want to try it.
2. Spoof-it :: a very sophisticated technique, the input is fed to a filter that 'takes out the noise'. This is a very sophisticated, new technique and unless you feel comfortable engineering auto-filters and possibly even a digital filter, we're talking bleeding edge (and I mean it in every way it can understood in any variation of English.) I would consider it a challenge . . . and a lot fun (folks will tell you that my concept of fun is not quite ordinary.)
3. Replace-it :: About the cost of the car if the link is accurate.
4. 12V-nonsense :: Without going into the details, there have been reports that a weak or failing 12V battery can cause a number of mysterious symptoms. I remember one report that replacing the 12V battery cured the twitchy steering . . . It has a 50 A. fuse so do not dismiss this hypothesis (or necessarily share it with the seller.)

The link shows the car is licensed to April 2011 . . . so unless there is some re-registration inspection, I think you have time. What we don't know, is whether you feel technically up to working on the car if the steering torque sensors turn out to be bad and it doesn't trace to the 12V battery.

Now there are some other cautions we need to go over:

• transaxle oil - this model needs an initial change schedule of ~30,000 miles (~50,000 km).
• traction battery - left unrun, the older traction batteries can suffer self-discharge, worse if via an electrolyte leak. Repairing a traction battery is not a trivial task but it can be done. We have at least one, known traction battery refurbishment company and reports of others. Fortunately, there is a bright German fellow who has replaced failed modules in the past. Also, we are gaining more battery insights over time.
• misc. inverter coolant pump, inverter coolant replacement, brake fluid replacement (due to humidity), transaxle failure (known but rare risk), wheel alignment

For the price, I think the car is a reasonable risk PROVIDED it is not critical to your employment and you feel handy with car tools. We can help you hack through low-cost options while you build up skills and reserves. We can also discuss how to handle the car to maximize vehicle life and minimize risk to the systems. BUT THERE ARE NO GUARANTES . . . this is the Internet and I could be:


Bob Wilson

ps. Driving check-list:

• speed related hum even in "N" - this is the signature of a failing transaxle . . . +$2,000 . . . walk away. Get the car up to a reasonable speed, say 80 km/h, and shift into "N". Listen for a hum that varies by the speed . . . the transaxle MG2 stator has burnt windings. It can be replaced but check "orange4boy" postings to see what is required.
• left or right turn 'noise' - potentially a bad wheel bearing
• clicking noise acceleration and coasting - potentially CVT drive is bad
• max AC - does it blow cold air (assumes AC is standard in UK version)
• tires - don't care, you're going to put better ones on after a four-wheel alignment and reading the wear pattern
• 12 V - age?

 

It is Thursday so I'm wondering if the OP backed out of the deal. Buying a used car is never easy and there are risks. I didn't want to scare him off but I also wanted to make him aware of what these risks may entail.

I went back to the link and noticed some type of holder or cradle on the dash. My first thought was cell phone cradle?

Bob Wilson

 

Hi Bob. How do you do this please? My gen 1 has been throwing faulty torque sensor codes so I have decided to pull the EMPS relay out and just drive it with"Armstrong Power Steering" activated instead. When I do this and erase the torque sensor codes I get a C1552 PIG power supply code which I can't seem to erase. I'd like the checking system to ignore that and let me go on my merry way without a PS and warning ! on my dash all the time. Any help much appreciated. I've tried pulling the 10-pin plug out of the EMPS ECU but that throws up other codes...