hi everyone.
i have Accord diesel 2.2 i-ctdi sport 2006.
the problem is speedometer doesnt work well.while gas pedal is fully pressed, speedo shows correct speed. when its released or running in neutral, speedo drops sometimes to zero, sometimes to higher value. it depends how fast im going. on motorway, 6th gear, speed around 80mph, speedo needle waves from 60 to 80mph. no warning lights or errors. also odometer do not count miles correctly. i mean when speedo shows 0, but im still driving, odometer do not count miles

theres two videos on youtube:
1st driving on street:
2nd driving on motorway:

 

The Honda shop manual for 03-06 Accords (V6 & IL4 engines) shows a self-diagnostic procedure for the gauge panel including odomenter/speedometer. It is too extensive to summarize. You will need a shop manual (assuming yours has same feature!) to follow the directions. You can purchase an e-manual from automanualsource.com (03-06 Accord) for $22.

good luck

 

had it cheched by one mechanic, he said its vehicle speed sensor on transmission. does this car has one?
still no fault codes.
who controls the speedo on this car? is it the same sensor for abs or sensor on transmission?

 

I looked at circuit diagram for gauge panel and source of speed signal is not identified. It may be the output shaft speed sensor in the trans, but not clear from shop manual (4-cyl Accord).

good luck

 

do you know where exactly this sensor is located?

 

No, I was looking at a 4-cyl gas shop manual.

good luck

 

On U.S. models (we have no diesel models), this is a description of the speedometer:

Speedometer
The speedometer is controlled by the power supply
circuit/controller area network controller built-into
the gauge control module. The power supply
circuit/controller area network controller receives
vehicle speed information from the ECM/PCM
through the fast controller area network transceiver
via the MICU system. The ECM/PCM receives
vehicle speed information from sensors within the
manual or automatic transmission.


The output shaft speed sensor is commonly used for the speedometer. It is highlighted in this parts diagram:



However, your issue can be due to something other than the speed sensor, such as a wiring issue or problem with the gauge control module, etc.

An issue with the output shaft speed sensor can set a powertrain trouble code.

 

thanks. will try to check for wiring and sensor on weekend

 

just to be more clear. is this the right part numer: 28820-PWR-013 for this sensor?
Aliexpress.com : Buy Genuine Transmission Speed Sensor/Pick up Sensor for Honda Accord/Civic/Element OEM# 28820 PWR 013 from Reliable sensor fuel suppliers on Seven Stars Auto Parts Store | Alibaba Group

 

Finaly fixed.
the problem was transmission output shaft speed sensor. Part number: 28820-PWR-013. Honda stealer was looking £80 for it, but I bought it from China for £20 including delivery and it worked. It wasnt easy to get to the sensor and take it out aswell as to put it back, because there is very limited space to work. I reached it from underneath the car.
so speedometer, odometer and cruise control working now as it should.
thanks for help.