High Idle Kit, LB7 Duramax | 2001-2004

This high idle kit gives you full manual control of the elevated idle on the 6.6L LB7 Duramax in 2001-2004 Chevy Silverado and GMC Sierra 2500HD and 3500HD trucks. You set and adjust the idle with your factory cruise control buttons, so there are no extra switches to mount or hide in the cab. We put this kit together and back it with the same troubleshooting steps our own techs use, listed below, so you can get it working right the first time.

Note: This kit will not work on medium duty trucks, because they already have a built in high idle.

Features

• Controls the elevated idle with the factory cruise control buttons
• Works only in Park or Neutral; cruise control works as before while driving
• No extra switches to mount on automatic transmission trucks
• Installs with a wire and terminal at the ECM and a connection at the brake switch

Benefits

A higher idle helps the engine warm up faster in cold weather and increases output from the charging system. It can also reduce engine wear when the truck has to idle for long periods.

What's Included

• (1) 18 gauge light green wire, 5 ft, with ECM terminal
• (1) Expandable wire loom
• (1) Instant tap wire connector
• (1) Snap bushing grommet
• (4) 4 in cable ties

Before You Order

• Trucks with the ZF6 manual transmission need an added switch. See the Frequently Asked Questions below.

Frequently Asked Questions

Will this affect the factory cruise control?
No. All cruise control functions work as they did before while driving. The cruise buttons only control the high idle while the truck is in Park or Neutral.

I just installed it and it isn't working. What now?
The most common issue is the connection of the high idle wire to the brake switch. It may help to strip the insulation on the high idle wire and a portion of the insulation on the green/white wire at the brake switch, twist the wires together and tape them, or better yet, add a drop of solder and then tape it.

If you're sure the connection is good and clean, check the green/white wire for power. You should see 12 volts in Park or Neutral with the brake pedal released.

If there is no power on that circuit, check the 10 amp BTSI fuse in the under hood fuse block. If the fuse is good, use a test light or meter to make sure you have power on both sides of the fuse.

If there is no power to the fuse, check the reverse lights. With the key on and engine off, put the gear selector in Reverse and see if the lights come on. If not, check the 20 amp B/U LP fuse in the under hood fuse block and replace it if needed.

The high idle turns off right after I activate it. Why?
The truck may be sensing vehicle speed, which cancels the high idle. Start the truck, make sure it's in Park, and rev the engine slightly while watching the speedometer. If the needle moves, something is making the truck sense speed when it shouldn't, such as a wiring issue or a speed sensor problem.

Will this work with a ZF6 manual transmission?
Yes. The ECM pin installation is exactly the same. The kit uses the shift interlock circuit, the safety feature that requires you to press the brake to shift out of Park, to supply power to the high idle. Manual transmission trucks don't have this feature, so we recommend installing a switch from an ignition hot circuit to the end of the wire that would normally attach to the brake switch. The switch must be on to activate the high idle with the cruise buttons. It is very important to turn the switch off while driving, or engine RPM will be limited. The limited RPM won't hurt anything, but it will make the truck very frustrating to drive. You can also use the switch as a valet mode.

Will this work on my medium duty truck?
No. Medium duty trucks already have a built in high idle, so this kit will not work on them.

For warranty information, see our Warranty Policy.