Skip to content
Tahoe / Yukon Service Manual

DTC U3000 (K85P Restraints Occupant Classification System)

DTC U3000 (K85P Restraints Occupant Classification System) Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC U3000 Control Module For symptom byte information, refer to Symptom Byte List. Circuit/System Description The internal fault detection is handled inside the control module. The symptom byte information is for engineering reference only. No external circuit diagnosis is involved. Conditions for Running the DTC The control module runs the program to detect an internal fault when power up is commanded. The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range. Conditions for Setting the DTC The control module has detected an internal malfunction. Action Taken When the DTC Sets The control module refuses all additional inputs. Conditions for Clearing the DTC A current DTC clears when the malfunction is no longer present. A history DTC clears when the control module ignition cycle counter reaches the reset threshold of 100, without a repeat of the malfunction. Diagnostic Aids When the ignition is turned ON, the K85P Restraints Occupant Classification System (ROCS) module performs tests to diagnose critical malfunctions within itself. When the ROCS module has completed the power-up mode, the module will establish communication with other related modules. The module will set DTC U3000, and communicate with other related modules that an internal fault DTC has been set. Reference Information Schematic Reference Data Communication Schematics Control Module References Connector End View Reference Master Electrical Component List Description and Operation Data Link Communications 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

  1. Ignition ON/Vehicle In Service Mode, engine OFF.
  2. Verify DTC U3000 is not set. ⇒ If DTC U3000 is set with symptom byte 55 or 99 2.1. Perform all necessary programming and setup procedures for the control module that sets the DTC. 2.2. Verify the DTC does not set. ⇒ If the DTC sets, replace the control module that sets the DTC. ⇓ If the DTC does not set 2.3. All OK. ⇒ If DTC U3000 is set active or in history with any symptom byte, except 55, or 99 Replace the control module that sets the DTC. ⇓ If DTC U3000 is not set
  3. All OK Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification For control module replacement, programming, and setup refer to: Control Module References