GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Vivant 🢒 DTC 🢒 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

Connector End View Reference

    •  Engine Control Module Connector End Views
    •  Engine Controls Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions
    •  Scan Tool Output Controls

Circuit/System Verification

Start the engine, observe the DTC information with a scan tool. DTC 054 should not set.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector of the carbon monoxide (CO) sensor.

    2. Important: The test lamp is used to load the circuit and may not illuminate.

  2. Ignition ON, connect a test lamp between the 5-volt reference circuit of the CO sensor and the negative battery terminal.

    3. 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. Test for 4.8-5.2 volts between the 5-volt reference circuit of the CO sensor and the negative battery terminal.
    4. ⇒If less than 4.8 volts, test the 5-volt reference circuit of the CO sensor for a short to ground or open/high resistance. If the circuit/connections test normal, replace the ECM.
    ⇒If greater than 5.2 volts, test the 5-volt reference circuit of the CO sensor for a short to voltage. If the circuit/connections test normal, replace the ECM.
  4. Ignition ON, test for less than 0.2 volts between the low reference circuit of the CO sensor and the negative battery terminal.
    5. ⇒If greater than 0.2 volts, test the low reference circuit of the CO sensor for a short to voltage. If the circuit/connections test normal, replace the ECM.
  5. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit of the CO sensor and the negative terminal of the battery.
    6. ⇒If greater than 5 ohms, test the low reference circuit of the CO sensor for an open/high resistance. If the circuit/connections test normal, replace the ECM.
  6. Test the signal circuit of the CO sensor for an open/high resistance, short to ground, or a short to voltage.
  7. If all circuits/connections test normal, test or replace the CO sensor.

Component Testing
  1. Ignition OFF, disconnect the harness connector of the carbon monoxide (CO) sensor.
  2. Connect a DMM between the signal circuit and the low reference circuit of the CKP sensor.
  3. Test for 10-14 ohms between the signal circuit and low reference circuit.
    4. ⇒If the resistance is not with in the specified range, replace the CO sensor.
  4. Connect a DMM between the 5-volt reference circuit and the low reference circuit of the CO sensor.
  5. Verify that the resistance changes while turning the adjusting screw of the CO sensor.
    6. ⇒If the resistance do not change, replace the CO sensor.
  6. If all circuits/connections 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.