SPN 84 - FMI 10 (Fault Code 242)

Vehicle Speed Sensor Circuit Tampering Has Been Detected - Abnormal Rate of Change

Vehicle Speed Sensor Circuit

Fault Code: 242
PID(P), SID(S): P084
SPN: 84
FMI: 10/10
Lamp: Amber

REASON: Vehicle Speed Sensor Circuit Tampering Has Been Detected - Abnormal Rate of Change. Invalid or inappropriate vehicle speed signal. Signal indicates an intermittent connection or VSS

EFFECT: Engine speed limited to maximum engine speed without VSS parameter value. Cruise
control, gear-down protection, and road speed governor will not work.

Circuit Description:
The vehicle speed sensor senses the speed of the tailshaft gear on the vehicle's transmission. This speed signal is then transmitted to the engine electronic control module (ECM) and converted into a vehicle speed.

Component Location:
The vehicle speed sensor is located in the rear of the vehicle transmission.

Shop Talk:
Verify that the feature settings for the vehicle speed sensor anti-tampering (Fault Code 242), application type and automatic transmission are set correctly. If any of these are set incorrectly for your specific vehicle and application, Fault Code 242 could occur erroneously.

Driving techniques such as driving for extended periods of time in lower gears can log Fault Code 242. Fault Code 242 can be logged if the driver attempts to defeat the road speed governor by repeatedly cycling the keyswitch.

Once the speed signal has been restored the fault code will go inactive once the keyswitch is on for 30 seconds and the ECM senses zero vehicle and engine speed.

Read More:
SPN 84 - FMI 2 (Fault Code 241)
SPN 661 - FMI 4 (Fault Code 238)


Subscribe to receive free email updates:

0 Response to "SPN 84 - FMI 10 (Fault Code 242)"

Post a Comment