Detroit Fault Codes SPN 84/FMI 5 – EPA10 – GHG14

11/12/2025

SPN 84/FMI 5 - EPA10 - GHG14

Vehicle Speed Sensor Open Circuit

NOTE: This SPN is broadcast to the Motor Control Module (MCM) via the Common Powertrain Controller (CPC).

SPN 84/FMI 5

Description:

1. Disconnect the Vehicle Speed Sensor (VSS).

2. Measure the resistance between pin 13 of the Common Powertrain Controller (CPC) connector #3 (21–pin) and pin 1 of the VSS.

1. If the resistance is greater than 3 ohms, repair the open between pin 13 of the CPC connector #3 (21–pin) and pin 1 of the VSS.

2. If the resistance is less than 3 ohms, Go to step 3.

3. Measure the resistance between pin 14 of the CPC connector #3 (21–pin) and pin 2 of the VSS sensor.

1. If the resistance is greater than 3 ohms, repair the open wire between pin 14 of the CPC #3 connector (21–pin) and pin 2 of the VSS.

2. If the resistance is less than 3 ohms, Go to step 4.

4. Measure the resistance between pin 13 and 14 of the CPC connector #3 (21–pin).

1. If the resistance greater than 10 K ohms, replace the VSS.

2. If the resistance is less than 10 K ohms, repair the short in the harness between pins 13 and 14 of the CPC connector #3 (21–pin).

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