Vehicle Speed Parameters

TM 9-2320-312-24-2

Troubleshooting Section

Input 11 to the ECM can be used for the connection

This parameter determines the functionality of

of a normally closed high pressure A/C switch.

the exhaust brake. The exhaust brake can be

The ECM has a built-in timer. The timer is used

programmed only as an exhaust brake to aid in

to prevent excessive cycling of the cooling fan

slowing the vehicle or the exhaust brake can be

clutch due to successive cycling of the A/C switch.

programmed to put a load on the engine in order to

Programming this parameter to 0 disables the

warm up the engine faster.

function. Programming depends on the refrigerant,

Table 131

and the design of the air conditioning system as

well as the use of the signal input. Program the

Manufacturer/

Alternatives

Default

timer to 1 second for the connection of this input to

Model

another system. Programming the timer to 1 second

"Exhaust Brake

"None"

also provides a time delay. This feature requires the

GM 530/540

Only"

"Exhaust Brake

"Fan Control Type" parameter to be programmed

Only"

to "On/Off" or to "Variable Speed Fan Option S".

GMT-560

"None"

"Warm Up"

Also, the "A/C High Pressure Switch" parameter

"Exhaust Brake

must be programmed to "J1/P1:41"or to "J1/P1:62"

Other

& Warm Up"

Only"

for GMT-560.

Table 127

"Warm Up Mode Idle Speed"

Manufacturer

Minimum

Maximum

Default

OCT01 and newer Personality Modules.

N/A

This parameter determines the idle speed of

600

0 seconds

Other

0 seconds

the engine until the engine reaches operating

seconds

temperature.

OCT01 and newer Personality Modules.

Table 132

Minimum

Maximum

Default

Table 128

700 rpm

1400 rpm

1000 rpm

Minimum

Maximum

Default

0 second

600 seconds

0 seconds

i01726906

"Fan with Engine Brake On"

Vehicle Speed Parameters

This parameter determines whether the cooling fan

SMCS Code: 1901

will turn on when the engine brake has been active

for at least two seconds. This feature requires the

"Vehicle Speed Calibration"

"Fan Control Type" parameter to be programmed

to "On/Off". An on/off fan must also be installed in

order for this option to be functional.

This calibration is used when the ECM is configured

to use a vehicle speed sensor that is connected to

Table 129

the ECM vehicle harness connector J1/P1:32 & 33.

Manufacturer

Alternatives

Default

The "Vehicle Speed Calibration" is the value that is

N/A

used by the ECM in order to translate the vehicle

speed signal into kilometers per hour (miles per

Other

"YES"

"NO"

hour). When a vehicle speed sensor is connected

to an ECM input, the "Vehicle Speed Input" must be

OCT01 and newer Personality Modules.

programmed to "J1/P1:32 & 33". This parameter

is programmed in pulses per kilometer (PPKM) or

Table 130

pulses per mile (PPM). This parameter must be

Alternatives

Default

programmed. If this parameter is not programmed,

253-02 Check Customer or System Parameters

"YES"

"NO"

(56) will become active. This parameter affects the

cruise control and the ECM speedometer signal.

"Exhaust Brake Configuration"

Also, this parameter can affect the PTO operation,

extended idle and trip totals.

OCT01 and newer Personality Modules.