Warning Lamp Circuit

421

TM 9-2320-312-24-2

Troubleshooting Section

If the Customer Parameter for Engine Monitoring

i01611513

is programmed to "WARNING", "DERATE", or

Warning Lamp Circuit - Test

"SHUTDOWN" the lamp will turn on when a warning

condition exists. The lamp will be turned on

SMCS Code: 7431-081

continuously while a warning condition exists.

System Operation Description:

If the Customer Parameter for Engine Monitoring

is programmed to "DERATE" or "SHUTDOWN",

Use this procedure under the following situation:

the lamp flashes whenever Engine Monitoring is

derating engine speed, vehicle speed, and power.

Use the following information in order to determine

if the warning lamp is operating incorrectly:

If the Customer Parameter for Engine Monitoring is

programmed to "SHUTDOWN", the warning lamp

The following background information is related

will continue flashing after the derate mode until

to the following procedure:

the engine is shut down. Refer to Troubleshooting,

"System Overview".

Warning Lamp Operation

Electrical Connection of Lamps

A warning lamp is required if the "Engine Monitoring"

feature is used. The warning lamp indicates an

One terminal of the lamp must be connected to

active problem with one of the monitored conditions

battery voltage through the vehicle wiring. The

such as high coolant temperature. A flashing

other terminal is connected to the ECM at the ECM

warning lamp indicates that the engine is derating

vehicle harness connector J1/P1 at terminal 29

power. The warning lamp will turn on for a minimum

(warning lamp).

of two seconds after the engine has started.

The ECM provides a path to ground in order to turn

With SEP00 software and newer software, an

the lamp ON.

option is available for the "GM Truck Manufacturer"

configuration that allows the output for warning lamp

to be configured as an output for a warning lamp for

high coolant temperature. The "Engine Monitoring

Lamps" parameter must be programmed to the

"Warning Lamp" option for standard operation of

engine monitoring. If the "Engine Monitoring Lamps"

parameter is programmed to the "HIgh Coolant

Temp Warning Lamp" option, the output is used

as an interface to the GM shutdown system. Refer

to Troubleshooting, "High Coolant Temp Warning

Lamp Output Circuit - Test" for details.

Operation Of Engine Monitoring

When the ECM has detected an engine condition

g00769338

Illustration 193

that exceeds the acceptable limits, the warning

Schematic for the circuit of the warning lamp

lamp will turn on. The activation of the lamp depends

on the existing conditions and the programming of

the parameter for "Engine Monitoring". The lamp will

activate in one of the following modes:

The lamp not only turns on, but the lamp stays on.

The lamp will flash on and off.

If the lamp turns on continuously, the engine is in

warning mode. If the lamp begins to flash, the ECM

has begun to derate engine speed, vehicle speed,

or power.

If the parameter for Engine Monitoring is

programmed to "WARNING", the lamp will not

flash. The lamp only flashes when the engine is

programmed to "DERATE" or "SHUTDOWN".