If your Audi Allroad’s power windows are exhibiting erratic behavior, moving only a few inches at a time before stopping, you’re not alone. This issue is common in older models and can be frustrating to diagnose. This article explores potential causes and troubleshooting steps using VCDS (VAG-COM Diagnostic System) for Audi Allroad power window problems, specifically focusing on a 1999 Audi A6 quattro Avant as a case study.
Understanding the Problem: Intermittent Power Window Operation
The primary symptom is the power windows moving in short bursts, regardless of the switch used (driver master switch or individual door switches). Holding the switch or using the key fob remote doesn’t change the behavior. Occasionally, complete unresponsiveness occurs for short periods. The windows move smoothly and don’t retract when stopping, ruling out the pinch protection feature.
Initial Troubleshooting Steps: Mechanical and Electrical Checks
Before diving into VCDS diagnostics, perform these preliminary checks:
- Visual Inspection: Inspect window regulators, gliders, and door wiring harnesses for damage, wear, or corrosion. Pay close attention to the wiring loom within the door, as it flexes repeatedly and can be prone to breakage.
- Comfort Control Module (CCM): Some Audi models utilize a CCM to manage power windows. However, certain years, like the 1999 A6 in our case study, may not have a dedicated CCM. Its functions are integrated into other modules.
- Central Locking Module: In the absence of a CCM, the Central Locking module may play a role in power window control. Inspect this module for water damage, corrosion, or loose connections. Check the under-carpet wiring and connectors as well.
VCDS Diagnostics for Audi Allroad Power Windows
While the case study vehicle predates OBD-II and CAN-bus systems (using K-line/KW1281 protocol instead), VCDS can still provide valuable insights.
- Auto-Scan: A full vehicle scan using VCDS can reveal fault codes related to the power window system, even on older models. The provided auto-scan log, however, shows no relevant fault codes for the power window issue. Focus on addressing the existing fault codes related to the rear right door lock (01562 – Can’t Unlock/Won’t De-Safe), as these could potentially impact the centralized locking system and indirectly affect the windows.
- Module Coding: The auto-scan log also reveals that the Interior Monitoring module (Address 45) has a coding suggesting a 3-door Audi A3. This discrepancy should be investigated. While unlikely to be the direct cause of the power window issue, incorrect coding can lead to unexpected behavior. Consult the Ross-Tech wiki for proper coding procedures for your specific Audi model.
Further Investigation and Potential Causes
If initial troubleshooting and VCDS diagnostics yield no clear solution, consider these possibilities:
- Power Supply: Check the power supply to the power window motors and control modules. A weak battery or faulty alternator can cause intermittent operation. Use a multimeter to verify voltage levels.
- Wiring and Ground Connections: Thoroughly inspect all wiring and ground connections related to the power window system. Look for loose connections, broken wires, or corrosion.
- Relay Issues: Faulty relays can cause intermittent power window problems. Locate and test the power window relays.
- Door Control Modules: Individual door control modules could be malfunctioning. While not specifically mentioned in the auto-scan, these modules can be a source of problems.
Conclusion
Troubleshooting intermittent power window issues in an Audi Allroad requires a systematic approach. Start with visual inspections and basic electrical checks. Utilize VCDS to scan for fault codes and verify module coding. If the problem persists, delve deeper into power supply, wiring, relays, and door control modules. Remember to consult resources like the Ross-Tech wiki for model-specific information and wiring diagrams. While this case study focused on a 1999 A6, the general principles apply to other Audi Allroad models experiencing similar power window problems. A thorough investigation combined with VCDS diagnostics is key to pinpointing the root cause and restoring proper functionality.
