GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 Yukon XL Denali 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC C0615, C0620, C0625, or C0630

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 C0615 08: Left Front Position Sensor Circuit Signal Invalid

DTC C0615 55: Front Position Sensor Circuit Expected number of transitions not reached

DTC C0620 08: Right Front Position Sensor Circuit Signal Invalid

DTC C0620 55: Right Front Position Sensor Circuit Expected number of transitions not reached

DTC C0625 08: Left Rear Position Sensor Circuit Signal Invalid

DTC C0625 08: Left Rear Position Sensor Circuit Expected number of transitions not reached

DTC C0630 08: Right Rear Position Sensor Circuit Signal Invalid

DTC C0630 55: Right Rear Position Sensor Circuit Expected number of transitions not reached

Circuit/System Description

The electronic suspension control (ESC) module supplies a 5-volt reference to all 4 suspension position sensors. The return signal represents the position of the suspension for the module to activate the dampers or the air compressor for load leveling.

Conditions for Running the DTC

C0615-C0630 08

The ignition is ON.

C0615-C0630 08

Vehicle speed greater than 0 km/h (0 mph)

Conditions for Setting the DTC

C0615-C0630 08

The ESCM detects the position sensor signal voltage below 0.35 volt or above 4.75 volts.

C0615- C0630 55

No activity from the position sensor when activity is detected on 2 or more other position sensors.

Action Taken When the DTC Sets
    •  System defaults to normal damping force state.
    • The SERVICE SUSPENSION SYS message will be displayed after 3 consecutive ignition cycles.

Conditions for Clearing the DTC

C0615-C0630 08

    • Position sensor signal voltage is between 0.35 to 4.75 volts
    • Allow 30 seconds for redetection after clearing codes.

C0615-C0630 55

    • Activity is detected on all 4 sensors.
    • Redetection requires driving the vehicle.

Diagnostic Aids
    • If this fault condition is set along with DTC C0696, diagnose DTC C0696 first.
    •  Verify the sensor link is attached.

Reference Information

Schematic Reference

Electronic Suspension Control Schematics

Connector End View Reference

Electronic Suspension Control 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

Circuit/System Verification

Driving vehicle, observe the scan tool ESC suspension position sensor voltage. The reading should change between 0.35-4.75 volts as road conditions change indicating the sensor is active and the link is attached.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the suspension position sensor.
  2. Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit terminal C and ground.
    3. ⇒If greater than 1 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ESC module.
  3. Ignition ON, test for 3.7-5.5 volts between the 5-volt reference circuit terminal A and ground.
    4. ⇒If less than 3.7 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ESC module.
    ⇒If greater than 5.5 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ESC module.
  4. Install a 3A fused jumper wire at the signal circuit terminal B. Toggle the jumper wire between the low reference circuit terminal C and the 5-volt reference circuit terminal A. Verify the scan tool position sensor voltage parameter toggles between 0.35-4.75 volts.
    5. ⇒If the position sensor voltage does not toggle between the min and max values test the signal circuit for a short to voltage, short to ground or an open/high resistance. If the circuit tests normal, replace the ESC module.
  5. If all circuits test normal, test or replace the suspension position sensor.

Repair Instructions
    •  Electronic Suspension Front Position Sensor Replacement
    •  Electronic Suspension Rear Position Sensor Replacement - Left Side
    •  Electronic Suspension Rear Position Sensor Replacement - Right Side
    •  Control Module References for ESCM replacement, setup, and programming

Repair Verification
  1. Install any components or connectors that have been removed or replaced during diagnosis.
  2. Perform any adjustment, programming or setup procedures that are required when a component or module is removed or replaced.
  3. Clear the DTCs.
  4. Use the scan tool Diagnostic Counter Reset output control function to bypass the 3 consecutive ignition cycle requirement for setting a DTC. This will ensure that if a DTC was to be reset during the repair verification process, it will be displayed on the scan tool.
  5. Turn OFF the ignition for 60 seconds.
  6. Turn ON the ignition.
  7. If the repair was related to a DTC, duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to the Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedure