Traxxas TQi Radio Systems
Before attempting to program your VXL-8s, it is important to make sure your TQi
transmitter is properly adjusted (set back to the factory defaults). Otherwise, you
may not get the best performance from your speed control.
The transmitter should be adjusted as follows:
1. Set the throttle neutral switch to the 50/50 setting. This adjusts the
transmitter’s throttle trigger throw to 50% for throttle and 50% for braking and
reverse. Experienced users may wish to use the 70/30 setting if more broad
proportional control is desired in forward than with braking and reverse. This
might be desirable in a racing environment where reverse is disabled.
2. Set the throttle trim control to the middle 0 setting.
3. You are now ready to program your speed control.
Aftermarket (Non-Traxxas) Transmitters
The following instructions are provided as a general reference only for those who
are using non-Traxxas transmitters. Consult your transmitter’s instructions for
information on how to change the settings.
1. Set the High ATV (adjustable travel volume) or EPA (end point adjustment) to the
maximum setting. This is the amount of servo throw at full throttle.
2. Set the Low ATV, EPA or ATL (low side only trim adjustment) to the maximum
setting. This is the amount of servo throw at full brakes or reverse.
3. Set the throttle trim to the middle (neutral setting).
4. Set the throttle channel reversing switch to either position. Do not change the
switch position after programming.
5. Set the trigger throw adjustment to 50% throttle and 50% brake (either
mechanical or electronic).
6. Set the exponential setting (if equipped) to the zero or fully linear setting.

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Troubleshooting Guide

This guide describes possible speed control problems, causes, and simple solutions.
Check these items before contacting Traxxas.
Steering channel works but the motor will not run:
• The speed control has thermally shut down. Allow the speed control to cool down.
Use a milder motor or a smaller pinion gear. Check the drive train for restrictions.
Check the motor connections. Check the motor.
• Make sure the speed control is plugged into the throttle channel of the receiver.
Check operation of the throttle channel with a servo.
• Bad batter(ies) or motor. Check the operation with known good batter(ies) and
motor.
• VXL-8s: Possible internal damage. Return the VXL-8s to Traxxas for service.
Motor runs backwards:
• Motor wired backwards - Check the wiring and correct.
Motor runs as soon as the battery is plugged in:
• Internal damage; return VXL-8s to Traxxas for service.
VXL-8s will not go into programming mode:
• Make sure the VXL-8s is plugged into Channel 2 (the throttle channel) on the
receiver. If it is plugged into the battery terminal, it will not go into programming
mode.
• Be sure the VXL-8s is turned off before trying to program or select a profile.
• Unplug battery, reconnect, and repeat programming instructions.
• Check if transmitter is turned on.
Receiver glitches/throttle stutters during acceleration:
• The receiver or antenna is too close to power wires or the batteries.
• Bad connections. Check the wiring and connectors.
• Motor worn. Replace the motor.
• Excessive current to motor (over-geared motor). Use a smaller pinion gear.
• Battery voltage low. Recharge and/or verify charged status.
• Disconnected brushless motor lead. Reconnect according to appropriate wiring
diagram.
Model runs slowly / slow acceleration:
• Check the motor and battery connectors.
• Check to see if the VXL-8s is in Profile #3 (50% throttle).
• Bad batter(ies) or motor. Check the operation with known good batter(ies) and
motor.
• Incorrect transmitter or speed control adjustment. Refer to the Transmitter Setup
and VXL-8s Setup Programming sections.
• VXL-8s is in Thermal Shutdown Protection. Allow to cool and check for proper
gearing.
• VXL-8s has entered Low-Voltage Protection.
Model will not go in reverse:
• Make sure the throttle trim is in the correct position (LED on VXL-8s should be lit
solid at neutral throttle).
• Check for correct VXL-8s profile (Profile #2 does not have reverse).