Talon Won't shift over 6k rpm

[Jefferson87]

Just went to pick up my x4 that's been at the dealer a month getting a new I4wd module and sub transmission.

They go to do a test drive and it won't shift at all over 6k rpm, in any mode. 2 dash marks come up on the display. Shift fine under 6k.

 

[HondaTech]

Have them check codes.

Is it reading consistent speed?

 

[Jefferson87]

Have them check codes.

Is it reading consistent speed?

They've been on it for a couple hours. I tried resetting the ECU. swapped ecu's with another good unit. I'm assuming the speedo was correct. He didn't mention it.

 

[PaulF]

The VS Sensor that feeds the speedo does NOT control anything concerning the DCT. It only feeds the speedo and Power Steering.

The Talon has 6 speed sensors and 2 of them control the DCT shifting.

The Rear VS Sensor is on the front of the sub trans.
The Fron VS Sensor is located on the front diff right in the middle above the ring gear.

If either of these 2 are not working, it will not shift correctly. Possibly the one on the SubTrans got broken or left unplugged.

 

[Jefferson87]

The VS Sensor that feeds the speedo does NOT control anything concerning the DCT. It only feeds the speedo and Power Steering.

The Talon has 6 speed sensors and 2 of them control the DCT shifting.

The Rear VS Sensor is on the front of the sub trans.
The Fron VS Sensor is located on the front diff right in the middle above the ring gear.

If either of these 2 are not working, it will not shift correctly. Possibly the one on the SubTrans got broken or left unplugged.

This is my guess. Weird that it worked fine for ~30 mins of testing and only has an issue above 6k.

 

[PaulF]

This is my guess. Weird that it worked fine for ~30 mins of testing and only has an issue above 6k.

It is not really that weird if you look at the DCT tune. Shifting tables are all based on RPM vs. OSS vs. TPS and if the one of those is missing (my guess is the rear OSS), it can't/won't shift as expected.

 

[906UP]

I don't think you can blame Honda for this one, it worked when you brought it in, doesn't work after the dealer techs worked on it.....hmmm

 

[PaulF]

Here is another tidbit. If you do an IGR on machine with a DCT, you MUST adjust/calibrate the Front and Rear VS Sensors or it will not shift properly or into 6th gear. It is because the RPM/OSS/TPS are not in close enough mesh and the PCM can't interpret the inputs properly.

 

[Jefferson87]

I don't think you can blame Honda for this one, it worked when you brought it in, doesn't work after the dealer techs worked on it.....hmmm

Not blaming honda, or anyone.

Here is another tidbit. If you do an IGR on machine with a DCT, you MUST adjust/calibrate the Front and Rear VS Sensors or it will not shift properly or into 6th gear. It is because the RPM/OSS/TPS are not in close enough mesh and the PCM can't interpret the inputs properly.

They actually put on a set of stock tires just to make sure. The machine doesn't know the tires are bigger, so I don't see what they were thinking there. The IGR I get, because it's f***ing with the relationship between the sensors on the transmission and the wheels.

I think you are probably right, that it is something with the sensor on the transmission. They just had it out, so maybe it got dirty or didn't seat all the way.

 

[PaulF]

I think you are probably right, that it is something with the sensor on the transmission. They just had it out, so maybe it got dirty or didn't seat all the way.

Another common issue with any type of automotive plug is that the connectors are not seated/clicked all the way in the plug housing so they work once during initial assembly but then don't make contact when plugged back in again because the connector/wire get pushed out of the connector a little bit. The hard part on those is it "looks" all plugged in but it really isn't.

 

[Jefferson87]

So would troubleshooting be as simple as unplugging 1 sensor, going for a drive, if no change. That's the sensor that is causing issues?

Or will it being completely unplugged cause a different issue?

 

[PaulF]

So would troubleshooting be as simple as unplugging 1 sensor, going for a drive, if no change. That's the sensor that is causing issues?

Or will it being completely unplugged cause a different issue?

Maybe and maybe. The problem with that is an intermittent or improperly reading sensor will not act the same as a completely broken or disconnected sensor. A disconnected VS sensor will trigger a dash light, set a code and not shift at all and stuck in 1st gear so according to your symptoms, I don't believe it (or any of the sensors) are completely disconnected or bad (but manuals have been known to be wrong before). My experience tells me a sensor is sending bad/inaccurate data to the ECU.

They are a Honda shop and should have the MCS. If it were me and I had the proper tool(s) I would connect the MCS and start comparing sensor data against known good data (like a properly shifting machine).

 

[Jefferson87]

Maybe and maybe. The problem with that is an intermittent or improperly reading sensor will not act the same as a completely broken or disconnected sensor. A disconnected VS sensor will trigger a dash light, set a code and not shift at all and stuck in 1st gear so according to your symptoms, I don't believe it (or any of the sensors) are completely disconnected or bad (but manuals have been known to be wrong before). My experience tells me a sensor is sending bad/inaccurate data to the ECU.

They are a Honda shop and should have the MCS. If it were me and I had the proper tool(s) I would connect the MCS and start comparing sensor data against known good data (like a properly shifting machine).

I'm not familiar with an mcs.

They seem to be over their head on the is machine. I think their techs have all been just bike guys for 35 years and now they are having to deal with these things.

 

[snuffnwhisky]

Make sure the rear VSS is hooked up. If it is, unplug it and replug. Also look for any damage to the wire or connector. They would have disconnected it to pull the subtrans out. Its right beside the dip stick for the subtrans. Check the other connections in that area also.

 

[Jefferson87]

Make sure the rear VSS is hooked up. If it is, unplug it and replug. Also look for any damage to the wire or connector. They would have disconnected it to pull the subtrans out. Its right beside the dip stick for the subtrans. Check the other connections in that area also.

View attachment 183791

I'm guessing the rear vss is the one I tied my reverse light trigger kit into? If so, that means there is 2 connections now. I never had an issue after I installed it, but maybe the tech didn't see the 2nd connection.

 

[snuffnwhisky]

I'm guessing the rear vss is the one I tied my reverse light trigger kit into? If so, that means there is 2 connections now. I never had an issue after I installed it, but maybe the tech didn't see the 2nd connection.

The VSS is completely separate from the reverse trigger. The Rear VSS is right beside where the front driveshaft goes into the sub transmission.

 

[Jefferson87]

Well they got it figured out, it was one of the connections on the sub transmission.

 

[906UP]

Well they got it figured out, it was one of the connections on the sub transmission.

Good now go beat the s*** out of it!!!

 

[Jefferson87]

Good now go beat the s*** out of it!!!

Right, so I can have it at the shop for another month?

 

[NTCPrezJB]

Right, so I can have it at the shop for another month?

If it does need to go back to the shop....I'd suggest a different shop.