08 High Idle Issue

Many have experienced a higher than normal idle on the 08 bikes with the TBW (throttle by wire) throttles. Some feel it is a problem with the bike but the MOCO is working on a possible fix for this.

It is mainly brought about when the idle is elevated just before shut down such as rolling on the throttle when shutting down, sometimes without knowing or realizing it.
Using the kill switch to shut down when the idle is not at a normal idle will also promote this condition. The ECM remembers the last known idle speed just prior to shut down.

What seems to work for many to eliminate this problem which can also be found in the manual is this procedure below.
It is the same procedure for a replacement of the twist grip sensor as it is to eliminate the stored higher throttle value when shutting down and rolling on the throttle which is what is giving some this problem.

Whenever a new twist grip sensor (or ECM) is installed, place the engine run/stop switch in the RUN position and turn the ignition/light key switch to IGNITION and then back to OFF four times (without starting engine). Allow at least ten seconds to elapse between ignition cycles. As the ECM uses the first four ignition cycles to establish the optimum idle speed, there may be initial performance problems if the procedure is not performed, such as high idle or hesitation when the throttle is opened.

Here's a more detailed view of this.

Turn the RUN switch to RUN, do not touch the throttle.

Turn on the IGNITION SWITCH, wait for the CEL (Yellow engine light) to turn OFF.

Turn off IGN only, wait for 10 seconds and repeat this sequence 3 more times.

After this, go to your dealer and get the NEW ECM Flash installed in the bike.

What it does is keeps the ECM awake for an additional 10 seconds and gives the TGS (throttle grip sensor) time to settle into a ZERO state, and it is a should be covered under the warranty and a free ECM Flash.

If they aren't aware of the fix, refer them to HDNet, there is a document that details the warranty procedure. Tech Tip 380


Here's TT # 380 on the high idle issue.

TT380 – June 12, 2008 - High Idle Complaints on 2008 Touring Models
High Idle Complaints on 2008 Touring Models
Due to ’08 Electronic Throttle Control calibration strategy parameters and throttle grip sensor
variability some customers have experienced intermittent changes in idle RPMs. This
condition is caused by a change in the zero position stored to memory in the ECM, as
determined by the last four readings seen at key OFF. This cannot increase engine speed
while riding but would change the idle RPM, similar to adjusting the throttle stop screw on a
carbureted model.
To correct this condition we will be making several changes to the throttle grip sensor to
reduce voltage variances and also update the way the calibration’s strategy looks at and
records these voltages. Completion of these changes and test validation will take several
months.
In the interim we have released revised calibrations in the latest version of Digital Tech to
alleviate the high idle concerns for those customers experiencing the condition. The current
software version (1.004.001) and details of the changes can be viewed by selecting the
What’s New button on the home screen of DTII. This info is also on h-dnet under:
Service>Tools & Equipment Info>DTII>Version Updates-What’s New. The new calibrations
will leave the ECM powered up for 10 seconds after key OFF to complete housekeeping,
allowing the rider more opportunity to release the throttle grip, so the throttle control can
return to true zero before the ECM power is shutdown. This should eliminate rider induced
zeroing issues. Additionally, the new calibrations will be less sensitive to voltage changes due
to an increased dead-band in the operating strategy. Under certain conditions and riding
styles some customers may notice a slightly different throttle feel, or comment on reduced
engine responsiveness. This is due to the increased dead-band and will feel similar to a loose
throttle cable adjustment on non-ETC vehicles.
Therefore, we recommend only reflashing vehicles for customers experiencing the high idle
concern and wait for the next version calibrations before updating vehicles on a wider scale.
SE Race Tuner and SE Super Tuner calibrations have not been updated at this time, and
reflashing a stock cal over a Tuner cal may only temporarily alleviate the high idle, until you
reflash back to a tuner cal.
It is recommended anytime you replace ECM, TGS or Reflash the calibration to cycle the Ign.
switch 4 times, waiting 10 full seconds after keying off between cycles, to relearn zero TGS
position.
The following warranty credit procedures will apply to domestic dealers only:
Warranty credit will be allowed for reflashing the calibration at the usual rate.
For OE calibrations including CVO, file an MC claim using labor code 7804 for 0.2 hours
labor.
For SWR’ed P&A calibrations, file a PNA claim using labor code 8209 for 0.2 hours labor.
Non-registered P&A performance calibrations will require preauthorization for warranty credit.
NOTE: Labor code 8209 is a new code and may need to be downloaded into your system