GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Vivant 🢒 HVAC 🢒 HVAC - Automatic 🢒 DTC 054

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 Descriptor

DTC 054: Carbon Monoxide (CO) Sensor Circuit

Circuit/System Description

The carbon monoxide (CO) adjuster is only used on vehicles that use leaded fuel. The CO adjuster is used in place of the oxygen sensor.

Conditions for Setting the DTC
    • The engine control system is in Open Loop.
    • The CO potentiometer is greater than 250 counts or the CO potentiometer is less than 5 counts.
    • The DTC runs continuously when the above conditions are met.

Diagnostic Aids

If a shared 5-volt reference circuit is shorted to ground or shorted to a voltage, other 5-volt reference circuits may be affected.

Reference Information

Schematic Reference

Engine Controls Schematics

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

Engine running, observe the DTC information with a scan tool. DTC 054 should not set.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the carbon monoxide (CO) sensor.
  2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit and ground.
    3. ⇒If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

    Important: The 5-volt reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.

  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit and ground.
    4. ⇒If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the ECM.
    ⇒If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Test the signal circuit for an open/high resistance, short to ground, or a short to voltage.
  5. If all circuits test normal, test or replace the CO sensor.

Component Testing
  1. Ignition OFF, disconnect the harness connector at the carbon monoxide (CO) sensor.
  2. Test for 10-14 ohms between the signal terminal and low reference terminal.
    3. ⇒If not with in the specified range, replace the CO sensor.
  3. Connect a DMM between the 5-volt reference terminal and the low reference terminal.
  4. Verify the resistance changes while turning the adjusting screw of the CO sensor.
    5. ⇒If the resistance does not change, replace the CO sensor.
  5. If all circuits test normal, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for engine control module replacement, setup, and programming.