Real Time Dampening (RTD) Diagnosis

Circuit Description
The suspension control module receives a vehicle speed signal input from the powertrain control module via the vehicle speed signal circuit and also receives vehicle speed data over the serial data class 2 circuit. Once vehicle speed has been detected, the suspension control module compares the two inputs for accuracy.


Conditions for Running the DTC
Continuously after vehicle speed has been detected from one or both inputs.


Conditions for Setting the DTC
Class 2 vehicle speed is greater than 32 km/h (20 mph) and the calculated speed input (hard wire) is less than 5 km/h (3 mph) continuously for 10 seconds.


Action Taken When the DTC Sets
^ Disable EVO outputs.
^ Stores a DTC C0550 in the suspension control module memory.


Conditions for Clearing the DTC
^ The suspension control module detects a vehicle speed signal from the PCM of greater than 32 km/h (20 mph).
^ Using a scan tool.
^ A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.


Diagnostic Aids

Important: Calibrate the suspension control module before replacement and cycle the ignition off and on to see if the DTC C0550 resets.

The replacement suspension control module must be calibrated when replacement is necessary.


Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
3. Tests whether the condition is module, system, or condition related.
4. Tests whether the condition has been corrected or identified as specified in the supporting text.
5. Tests for an open or short in the vehicle speed circuit of the suspension control module.