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Discussion Starter #121
I got my car back from the repair shop with no charge for the inspection/test drive so I got my expected outcome.

Re: the possibility that the speedometer is wrong:
How does the speedometer determine the vehicle's speed?

Re: IMA Motor Rotor Position Calibration
What are the symptoms of an incorrect rotor calibration or position?
 

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Re: the possibility that the speedometer is wrong:
How does the speedometer determine the vehicle's speed?
As far as I know, most cars use a sensor on the transmission output to measure speed. I can't imagine why the CR-Z would be any different.
 

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Discussion Starter #123
As far as I know, most cars use a sensor on the transmission output to measure speed. I can't imagine why the CR-Z would be any different.
OK, so that Pick-Up Assembly/Transmission Speed Sensor in the Clutch Release assembly is indeed the Vehicle Speed Sensor. If it is reading the countershaft RPM per FARMERGILES, then am I correct in thinking a change in only the final drive gear ratio would not cause the speedometer to display a different speed?
 

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then am I correct in thinking a change in only the final drive gear ratio would not cause the speedometer to display a different speed?
Correct.
There is no comment in the manual about what happens if the rotor position calibration is not done.
I have bought a HDS from ebay so I will plug it into my car and check if I have any dtcs when the IMA warning light came on a couple of weeks ago. I will also see what ecus and options there are re the rotor position. Hopefully there will be notes available to help with the options.
 

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Discussion Starter #125
OK! So something else is causing the difference in the speedometer readings I'm seeing. Or the 70 MPH I consistently saw from when I bought the car up until the transmission was rebuilt, was somehow incorrect and now it's showing the correct speed of 75 MPH because it matches what other drivers see. "Curiouser and curiouser!"

I did a quick Google Search for "IMA Motor Rotor Position Calibration DTC" and found this:
It might help explain the IMA warning light in your car. My car doesn't have any warning lights though, and I expect if there were DTCs, that the dealer would have seen them when they ran the diagnostics.
 

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I think my IMA was due low 12v battery combined with very short journeys, low temps so seat heating on, and 3 engine starts in 10miles, with max speed of 40mph, plus some hills and junctions. It went off after the first restart.
It is hard to explain why your car appears not to have had the correct FD in the first place.
Have you had the car from new? (could a previous owner have had a replacement gearbox fitted from an older model?)
 

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OK, so that Pick-Up Assembly/Transmission Speed Sensor in the Clutch Release assembly is indeed the Vehicle Speed Sensor. If it is reading the countershaft RPM per FARMERGILES, then am I correct in thinking a change in only the final drive gear ratio would not cause the speedometer to display a different speed?
It doesn't read speed off the countershaft it reads it off a reluctor disc on the diff. The diff bolts to the crown wheel.

Secondly any change in final drive will result in speed difference.

This is why your travelling faster for a given rpm. The vss is reading accurately but the ratio has changed so the road soeed changes.
 

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Try this (found in a thread on an different Honda Hybrid forum where regen charging has stopped working).
Do it on a warm engine.
Disconnect the 12v battery for a couple of minutes.
Then restart and rev engine to 5000rpm for a few seconds. (hence warm engine)
Drive the vehicle.
 

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It was claimed it resets the ecus and clears any codes. The revving is to make sure the charge meter is calibrated.
Since it costs nothing and won't do any harm, its worth a try, although I doubt it will make any difference.
 

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All of these supposed resets are a waste of time and can clear actual codes that may have accumulated and can force other things to reset that would then need a specified process to re-calibrate. If the process is not in the Factiory service manual it is people making assumptions and trying feel good guessing.
 

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What harm would it do? None, same as replacing the 12v battery.
Its all very well having a negative view on these suggestions and others (eg full diagnostics, actuator tests and MCM & PCM firmware update, but at least I am attempting to help the OP.)
It's entirely up to him what he does.
 

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Lets agree to disagree but as has been discussed here it is the Final drive ratio that is probably now wrong since the transmission repair. These resets can cause other things Like I said to become mis-calibrated. If there is any benefit it will be short lived and not actually resolve the issue. It will be a temporary solution and not actually solve the problem. I am all for diagnostics if they are related to the issues and are warranted by the processes in the Factory Service manual not just resetting things and testing things because you can. Just because you can does not mean you should. There have been hundreds of postings on this forum where someone ( I even used to say it myself) says to disconnect the battery and reconnect it for X issue. These resets can cause harm if something gets set wrong like a Crank position sensor or IMA rotor etc. there are specified processes for calibrating these and other items. If battery is dead yes replace it and pray everything will be ok (If you do not have car checked and re-calibrated)but disconnecting the battery and resetting will be a temporary fix not a solution. The solution is proper diagnostics and replacing what is proved damaged or wrong.

The issue is the transmission and brake regeneration nothing else and it is throwing no codes.

Even if there are no codes data is collected that might help diagnose and repair the issue clearing everything loses all data the car may have collected that may speed repair.

If it is fixed by this resetting then I will admit I am wrong but there is no way that a simple reset will solve this issue without replacing a hard part.

It will not help the OP what will as it is a very specific issue is proper diagnostics by a knowledgeable shop who listens. Not forum members who think they may have a possible understanding of what is wrong. This needs knowledgeable professionals not speculation voodoo processes and shot gun approaches that can make it even harder to fix..

What harm would it do? None, same as replacing the 12v battery.
Its all very well having a negative view on these suggestions and others (eg full diagnostics, actuator tests and MCM & PCM firmware update, but at least I am attempting to help the OP.)
It's entirely up to him what he does.
 

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When Honda's software engineers were programming the DTCs and warning light illumination they would not include faults that cannot be anticipated, such as the wrong FD being fitted. This means the fault, although present does not cause a DTC, nor freeze frame data, as well as no warning lights or messages, making diagnosis very difficult.
But by doing an ecu reset ( a battery disconnection doesn't usually clear DTCs on newer vehicles), maybe the fault will be cleared, if only temporarily. If the regen charging works normally for a short time, it suggests that the various sensors are working.
I would be wary of changing the FD due to the expense, until I had ruled out all other possibilities.
 

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I am done with this topic the OP has been given advice and has a few solutions that have been suggested. At this point he has the details of the issue. A suspected reason why the car is doing what it is doing and at this point if he wants to fix it he has no choice but to pay a good technician to resolve it. It all goes back to a transmission replacement and all issues relate to that so it is a transmission issue. The shops that worked on it do not want to accept responsibility and they just want him to go away. If he wants it fixed it needs to be restored to factory specificatoins by a certified knowledgeable mechanic who is certified in transmissions. If they were a Honda Specialist that would be best.
 

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Discussion Starter #137
If disconnecting the 12 V battery could fix the regen issue, then that should have happened when I got a new 12 V battery last May. Even if the CHRG meter or IMA battery charge level meter are not displaying properly, I can tell by the lack of performance off the line that the IMA battery is at a low charge level much more often than before the transmission was repaired.

My plan is to find a mechanic or shop that will teardown the transmission and can hopefully identify the countershaft and final driven gear by part numbers. Since those gears will be exposed, I'm thinking of double checking the current final drive gear ratio by asking for photographs of the final drive and final driven gears so that their respective number of teeth can be counted.
 

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Zippy, you should take a look at the IMA data you can read with a Honda HDS diagnostic tool on this thread.
When I have my HDS working I will record the same data so you have something to compare yours with. (Peter's has the older NIMh batteries so his data can't be compared to yours.)
In the PGM1 data, you can see that there is engine rpm, vehicle speed, and countershaft rpm.
 

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Discussion Starter #139
How is the countershaft RPM value obtained? If the VSS measures the reduction gear in the differential, does that mean the countershaft RPM is derived/calculated and not directly measured? Or is there another sensor somewhere in the drivetrain that supplies the information for the countershaft RPM?
 

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The workshop manual says it measures the countershaft rpm as does the ecu data. Tank says the sensor reluctor is attached to the diff/crown wheel, ie on the FD side of the pinion. If the workshop manual is correct (more likely not) then the speed would not change otherwise it would change if the FD has chnanged.
If you compared VSS and countershaft rpm you would see if the FD had been changed. I should be able to tell you what the relationship is on my 2013 car so you can compare it with yours.
 
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