GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 XLR 🢒 Engine 🢒 Engine Electrical 🢒 DTC C0800

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 C0800 03: Device Power 1 Circuit Voltage Below Threshold

DTC C0800 07: Device Power 1 Circuit Voltage Above Threshold

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

IGN

C0800

C0800

--

--

Ground

--

C0800

--

--

Circuit/System Description

The adaptive cruise module (ACM) monitors the Ignition 1 voltage circuit to determine if the voltage is within the normal operating range. When the ACM detects that the Ignition 1 voltage is below 9.2 volts or above 16 volts, the DTC C0800 sets.

Conditions for Running the DTC
    • Ignition is in RUN.
    • Vehicle moving at a speed greater than 40.2 km/h (25 mph).

Conditions for Setting the DTC

C0800 03

    • The ACM detects that the ignition 1 voltage is less than 9.2 volts.
    • The above condition is present for 7 seconds.

C0800 07

    • The ACM detects that the ignition 1 voltage is greater than 16 volts.
    • The above condition is present for 7 seconds.

Action Taken When the DTC Sets

The following actions occur:

    • Loss of adaptive cruise function
    • The DIC displays the Cruise Not Ready message.

Conditions for Clearing the DTC
    • The DTC becomes history when the fault is no longer present.
    • A History DTC clears after 100 malfunction-free ignition cycles.
    • The ACM receives a clear code command from the scan tool.

Diagnostic Aids
    • A high or low voltage DTC set in multiple modules indicates a concern in the charging system.
    • A possible cause of this DTC could be overcharging with a battery charger or jump starting.
    • A high or low voltage value in multiple modules indicates a concern in the charging system.

Reference Information

Schematic Reference

Cruise Control Schematics

Connector End View Reference

Component Connector End Views

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. Verify DTC  C0800 is set as current.
  2. Engine running, measure and record the voltage at the battery terminals.
  3. Verify that the battery voltage is 12.6-15.5 volts.
    4. ⇒If the battery voltage is not within the specified range, refer to Charging System Test
  4. Engine running, observe the scan tool ignition voltage signal parameter.
  5. Verify that the scan tool displays a value that is within 2  volts of the battery terminal voltage.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the adaptive cruise module (ACM).
  2. Ignition OFF, test for less than 3 ohms between the ground circuit terminal 12 and ground.
    3. ⇒If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify a test lamp illuminates between the Ignition 1 voltage circuit terminal 14 and ground.
    4. ⇒If the test lamp did not illuminate , test the circuit for an open/high resistance.
  4. If all circuits test normal, test or replace the ACM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ACM replacement, setup, and programming