Steering Controls

Circuit Description
The electronic brake/traction control module (EBTCM), transmits a processed vehicle speed signal (VSS) from terminal 23 to terminal 4 of the Power Steering Control Module (PSCM). The PSCM uses the speed signal and the characteristic curve programmed in the microprocessor to determine the electric current variable for the power steering fluid flow control valve actuator.

Conditions For Setting the DTC
The power steering control module detects that the speed signal is no longer present at terminal 4.

Action Taken When the DTC Sets:
^ Power steering assist will default to partial manual steering.
^ The PSCM will store a code 21 in memory.

Conditions for Clearing the DTC:
^ Conditions for the fault are no longer present.
^ Using the scan tool.

Diagnostic Aids
^ Check for system voltage at terminal 6 with the key on and the engine off.
^ Check the ground circuit at terminal 8. Typical voltage drop readings are 500mV or less. When measuring the resistance it should measure at close to O (zero) ohms.
^ Use Terminal Repair Kit J 38125-A or J 35616-A to gauge all terminal contacts. Check for damaged connectors and poor wire to terminal connections.
^ If the DTC is an intermittent DTC try performing the tests shown while wiggling wiring and connectors, this can often cause the malfunction to appear.

Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
2. This step checks to see if the speedometer is operating properly.
3. This step checks for the speed signal input into the power steering control module.
5. This step replaces the power steering control module.