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Tahoe / Yukon Service Manual

DTC C1194, C1195, or C1197

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 C1194 Air Reservoir Pressure Below Threshold DTC C1195 Air Reservoir Progress Level DTC C1197 Leveling Compressor Motor For symptom byte information, refer to Symptom Byte List. Circuit/System Description There is a single pressure sensor, internal to the Air Suspension Controller. It provides a signal to the K5 Automatic Level Control Module which interprets the voltage to determine the pressure and airflow in the system. Monitors progress when the system is attempting to charge the reservoir to determine proper airflow and pressure. Conditions for Running the DTC Ignition ON System voltage is 9–16 V Active charge event/periodic system pressure check Conditions for Setting the DTC C1194 The K5 Automatic Level Control Module determines that the pressure in the air reservoir is below the functional threshold for 5 seconds. C1195 The K5 Automatic Level Control Module determines the airflow in the Air Suspension Controller during recharge event is slower than .01 bar/sec or faster than 2 bar/sec. C1197 The K5 Automatic Level Control Module measures the manifold pressure in the Air Suspension Controller is greater than 5 bar for 7 seconds.. Action Taken When the DTC Sets System offline. Speed limited possible. The K5 Automatic Level Control Module sends a message to the instrument panel cluster to display SERVICE LEVELING SYSTEM message. Conditions for Clearing the DTC A present DTC will clear on the next consecutive malfunction-free ignition cycle. A history DTC will clear after 41 consecutive malfunction-free ignition cycles. Diagnostic Aids If there is a reservoir fault, system will operate slower, using only compressor. If condition occurs more often in freezing temperatures, moisture/contamination is likely cause. Inspection should include check for intake hose twisting or obstructed. Inspection should include check for leak at air tank or air line between compressor and air tank. Reference Information Schematic Reference Electronic Suspension Control Schematics Connector End View Reference Master Electrical Component List Description and Operation Automatic Level Control 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.
  2. Using a scan tool, perform the control function Pneumatic Connection Pressure Test.
  3. Verify Pneumatic Connection Pressure Test passes and reservoir pressure is 4–20 bar. ⇒ If test fails or pressure is not 4–20 bar Inspect the reservoir, compressor, and related air lines for damage, improper seating, or evidence of water/ice in the system. ⇓ If test passes and pressure is 4–20 bar
  4. Using the scan tool, perform control functions Test Compressor Pneumatic Operation.
  5. Verify the compressor runs and test passes. ⇒ If compressor doesn’t run, or test fails 5.1. Verify compressor air lines and fittings are not damaged or leaking. ⇒ If damage or leaking is found Repair damage or leaking air lines or fittings ⇓ If damage or leaking is not found 5.2. Replace the G4 Automatic Level Control Air Compressor. ⇓ If compressor runs and tests pass
  6. Replace the Air Suspension Controller.
  7. Clear DTCs. Operate system under the Conditions for Running the DTC.
  8. Verify DTCs do not reset. ⇒ If DTC sets Replace the K5 Automatic Level Control Module ⇓ If the DTC does not set
  9. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Air Suspension Controller Replacement Control Module References for K5 Automatic Level Control Module replacement, programming and setup.