The Gm Dtc U1510-00 indicates a problem with the Local Interconnect Network (LIN) bus communication. This diagnostic trouble code (DTC) can cause a check engine light (CEL) or malfunction indicator lamp (MIL) to illuminate. While a vehicle may run without noticeable issues, addressing this code is crucial. This article outlines a real-world diagnosis and repair of a U1510-00 code in a 2017 Chevrolet Silverado LTZ 6.2L.
Understanding the U1510-00 Code and Initial Diagnosis
A U1510-00 code often points to a communication fault on the LIN bus. Research revealed a technical service bulletin (TSB) linking this code to a potential ground (G102) failure, often accompanied by intermittent headlight issues. In this case, the Silverado exhibited no lighting problems. However, the G102 ground was inspected. Despite appearing corroded, it tested at approximately 50mV under load with high beams activated, indicating no significant ground issue. The ground was cleaned, but the reading remained unchanged.
Narrowing Down the Culprit: The Active Grille Shutter
Consulting the vehicle’s network diagram revealed the Active Grille Shutter Motor Module as the sole module communicating with the Powertrain Control Module (PCM) on the affected LIN bus. This significantly narrowed the diagnostic scope. Accessing the module involved removing the trip panel above the radiator and grille to locate connector X132.
Analyzing the LIN Bus Waveform
Using an oscilloscope, the communication wire (GREEN/VIOLET) at connector X132 was probed to analyze the LIN bus waveform. Initially, the waveform appeared normal. However, closer inspection showed the bus voltage being pulled down to only 7 volts, instead of the expected battery voltage (around 12 volts). This deviation suggested a problem within the Active Grille Shutter module, its power supply, ground connection, or wiring between the module and connector X132.
To confirm, connector X132 was disconnected and the waveform re-analyzed. The bus voltage now correctly pulled down to ground, confirming the issue was isolated to the circuitry connected to X132.
Confirming Power and Ground to the Active Grille Shutter
Load testing the power and ground circuits of the Active Grille Shutter module showed no issues, eliminating those as potential causes. This pointed definitively to a faulty Active Grille Shutter Motor Module.
Resolution: Replacing the Active Grille Shutter
Replacing the Active Grille Shutter Motor Module resolved the U1510-00 code and the CEL/MIL illumination. This case highlights the importance of systematically diagnosing communication issues on the LIN bus, using tools like oscilloscopes and network diagrams to pinpoint the root cause.
