Lingenfelter L460160000 Lingenfelter RPM-003 RPM Activated Switch Instructions v1.5 - Manual (Page 12)

Connecting and enabling a tachometer signal on an ECM
with no existing tachometer wire (GM E38, E67 ECM's)
On some vehicles (such as the 2010-2014 Camaro, 2007-2013 C/K Trucks, and 2009-2014 CTS-V),
the tachometer is not connected to the ECM by a direct tachometer signal wire. Instead, the
dash receives the RPM signal via some other method (such as serial data or CAN). In most
cases, however, the vehicle’s ECM has an unpopulated pin that can be used to communicate the
tachometer signal from the ECM to an external device, such as the RPM-003. The following steps
explain how to connect a wire to the correct pin on the ECM, as well as how to enable the ECM
tachometer output using EFILive Tune v7.5.
Populating the Tachometer signal wire on the ECM (GM E38, E67 ECM's)
1. Determine the correct ECM pin location for the engine speed (tachometer) output signal on your vehicle. A list of
tachometer signal pin locations for some GM vehicles has been provided on page 14.
2. Disconnect the ECM connector that houses the tachometer output signal terminal. Use a small flat head screwdriver to
open the wire enclosure on the back side of the connector. This exposes the wires as they come out of the connector.
3. If there is a terminal cover on the front side of the connector, use a small flat head screwdriver to remove it by prying up
on each end. You should now see the terminals of each wire, along with colored terminal plugs in pin locations that are
not currently populated.
4. Locate the ECM’s engine speed (tachometer) output signal pin location on the connector. Remove the colored terminal
plug from the connector with a small screwdriver.
5. Crimp a terminal (PN: 0334680003 -- for E38/E67 ECM's) to a piece of wire (long enough to reach from the ECM
to the RPM-003 harness), which will become your tachometer output signal wire. The terminal will lock into the
connector when oriented correctly, so make sure that you have the terminal correctly oriented before attempting
to insert the terminal into the connector.
6. Insert the terminal into the correct pin location from the back side of the connector. You should here an audible “click,”
which tells you that the terminal was inserted in the correct orientation and has locked into place.
7. Reinstall the terminal cover, close the connector wire enclosure, and reinstall the connector onto the ECM.
8. This wire can now be connected to the white Tach input wire on the RPM-003.
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E38 ECM E67 ECM
Connector C1 Connector C2 Connector C3 Connector C1 Connector C2