Skip to content
Tahoe / Yukon Service Manual

DTC U3000 ((K43 Power Steering Control Module))

Diagnostic Instructions Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach. Diagnostic Procedure Instructions provides an overview of each diagnostic category. DTC Descriptors DTC U3000 44 Control Module – Data Memory Malfunction DTC U3000 49 Control Module – Internal Malfunction DTC U3000 4B Control Module – High Temperature DTC U3000 51 Control Module – Not Programmed DTC U3000 54 Control Module – Missing Calibration Symptom Byte Information: Symptom Byte List Circuit/System Description The power steering control module is paired to the power steering assist motor, and mounted to the steering gear. The power steering control module has the ability to detect and report internal malfunctions or missing data within the software. Conditions for Running the DTC Ignition ON. Power steering system voltage is 9–16 V U3000 4B – Repetitive steering input applied. Conditions for Setting the DTC The power steering control module detects an internal malfunction, experiences a high temperature event, or is missing programming or calibration. Action Taken When the DTC Sets The DTC is stored in memory. A “SERVICE POWER STEERING” message may be displayed on the instrument cluster. No steering assist or reduced steering performance. Conditions for Clearing the DTC A history DTC will clear after 40 consecutive malfunction free ignition cycles. Diagnostic Aids DTC U3000 4B does not indicate that a malfunction has occurred. Rather that the power steering control module had to limit current to the power steering motor to avoid thermal damage to the power steering system components. Discuss with the customer about driving conditions when the steering assist was reduced. Ensure that no steering components down stream of the power steering column assembly, such as ball joints, tie rod ends, universal joints, or the steering gear assembly, are mechanically binding. Reference Information Schematic Reference Power Steering Schematics Connector End View Reference Master Electrical Component List Description and Operation Power Steering System Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References for scan tool information. Circuit/System Verification DTC U3000 44 or U3000 49

  1. Verify that DTC U3000 44 or DTC U3000 49 is not set. ⇒ If the DTC is set Replace the K43 Power Steering Control Module . ⇓ If the DTC is not set
  2. All OK. DTC U3000 4B
  3. Verify that the DTC sets outside the conditions for running and setting. Since most occurrences of this DTC are caused by excessive driver inputs, review with the customer the conditions under which the DTC set. ⇒ If the DTC did not set outside of the conditions for running and setting 1.1. Ignition ON. 1.2. Operate the vehicle within the conditions that the customer experienced, avoiding excessive inputs, and verify the DTC does not reset. ⇒ If the DTC is set 1.2.1. Verify that no steering components down stream of the power steering column assembly are mechanically binding. Refer to Steering Effort Hard in One or Both Directions ⇒ If steering components are mechanically binding, replace the mechanically binding steering components. ⇒ If no steering components are mechanically binding, replace the K43 Power Steering Control Module. ⇓ If the DTC is not set 1.3. All OK. ⇓ If the DTC set outside of the conditions for running and setting
  4. All OK. The power steering is operating as designed. DTC U3000 51 or DTC U3000 54
  5. Ignition ON.
  6. Verify DTC U3000 51 or DTC U3000 54 is not set. ⇒ If DTC U3000 51 or DTC U3000 54 is set 2.1. Program the K43 Power Steering Control Module. 2.2. Verify the DTC does not reset. ⇒ If the DTC resets, replace the K43 Power Steering Control Module. ⇓ If the DTC does not reset 2.3. All OK. ⇓ If DTC U3000 51 or DTC U3000 54 is not set
  7. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Control Module References for control module programming and setup.