0084-01 Loss of Vehicle Speed Signal (31)

107

TM 9-2320-312-24-2

Troubleshooting Section

Expected Result:

i01638676

0084-02 Invalid Vehicle Speed

Results:

Signal (36)

OK STOP.

SMCS Code: 1900

i01638665

Conditions Which Generate This Code:

0084-01 Loss of Vehicle Speed

The "VSL Protection" is programmed less than

Signal (31)

2120 rpm, and the vehicle speed is constant when

the engine parameters indicate that the vehicle

SMCS Code: 1900

speed should be changing. This diagnostic code

will not occur if the "VSL Protection" parameter is

Conditions Which Generate This Code:

programmed to 2120 rpm.

The ECM does not detect vehicle speed when

Note: This code typically occurs when someone has

conditions indicate that vehicle speed should be

tampered with the vehicle speed signal.

present. This diagnostic code will not occur if the

"VSL Protection" parameter is programmed to 2120

System Response:

rpm.

Electronic System Response Engine rpm is limited

System Response:

to the programmed "VSL Protection" for one hour. If

the ECM is providing the speedometer signal, the

Electronic System Response The ECM will limit

speedometer will reflect the loss of speed when the

engine rpm to the programmed "VSL Protection". If

problem occurs and the vehicle is moving.

the ECM is providing the speedometer signal, the

speedometer will reflect the loss of speed when the

Service Tool Display or Lamps Caterpillar

vehicle is moving and the problem occurs.

Electronic Technician (ET) will display "DIAG" next

to "Vehicle Speed" on the status screen while the

Service Tool Display or Lamps Caterpillar

diagnostic code is active.

Electronic Technician (ET) will display "DIAG" next

to "Vehicle Speed" on the status screen while the

Engine Response The driver may think that the

diagnostic code is active. The Check Engine Lamp

engine power is low and that the engine is unable

will illuminate.

to reach the expected rpm. The derate will remain

for one hour after the fault is no longer active.

Engine Response The driver may think that the

engine power is low and that the engine is unable

Troubleshooting:

to reach the expected rpm.

Perform the following diagnostic procedure: "Vehicle

Note: A fuel system restriction has been known to

Speed and Speedometer Circuit - Test"

cause this diagnostic code although this occurrence

is not common. This situation exists because the

Results:

injectors are unable to provide sufficient fuel in

order to achieve the desired rpm under normal load

OK STOP.

conditions. Because the ECM cannot reach the

desired rpm under the normal load conditions, the

ECM suspects that the vehicle is under load. This

i01638681

should only occur when the vehicle is in motion.

0084-08 Vehicle Speed Out of

Range (36)

Troubleshooting:

Check the fuel pressure in order to ensure that

SMCS Code: 1900

a fuel system restriction is not the cause of the

problem when the vehicle is not moving.

Conditions Which Generate This Code:

Perform the following diagnostic procedure: "Vehicle

The "VSL Protection" parameter is programmed less

Speed and Speedometer Circuit - Test"

than 2120 rpm and the vehicle speed is greater

than 204 km/h (127 mph) for at least two seconds.

Results:

This diagnostic code will not occur if the "VSL

Protection" parameter is programmed to 2120 rpm.

OK STOP.