A VCDS (Vag-Com Diagnostic System) scan revealing glow plug circuit faults can be a common issue in diesel engines. This article will focus on understanding these fault codes, specifically using the example of fault codes 17055, 17056, 17057, and 17058, often found in VW TDI engines. We will explore potential causes and troubleshooting steps to resolve these issues.
Understanding Glow Plug Circuit Fault Codes
Fault codes 17055, 17056, 17057, and 17058 specifically indicate an electrical fault in the glow plug circuit for cylinders 1, 2, 3, and 4 respectively. These codes, often accompanied by a P0671, P0672, P0673, and P0674 designation, signal a problem within the electrical system that powers the glow plugs. A “Check Glow Plugs Vcds” scan result like this indicates the need for further investigation.
Common Causes of Glow Plug Circuit Faults
Several issues can trigger these fault codes:
- Faulty Glow Plugs: The most common culprit is a failed glow plug. Over time, glow plugs can wear out and fail to heat properly.
- Damaged Wiring/Harness: A damaged or corroded wire or connector in the glow plug harness can disrupt the electrical circuit. This can include damage to the harness boot.
- Faulty Glow Plug Relay: The relay responsible for supplying power to the glow plugs may be malfunctioning, preventing them from receiving the necessary voltage.
- ECU Issues: In rare cases, a problem with the engine control unit (ECU) can cause these fault codes.
Troubleshooting Glow Plug Circuit Faults with VCDS
Using VCDS, you can systematically diagnose the problem:
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Check Measuring Values: Within VCDS, access the measuring values for the glow plugs. This will display the voltage or current supplied to each glow plug. This data helps identify if a specific glow plug is not receiving power.
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Glow Plug Resistance Test: Using a multimeter, measure the resistance of each glow plug. A faulty glow plug will typically have a resistance outside the specified range. Compare your readings to the manufacturer’s specifications.
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Harness Inspection: Visually inspect the glow plug harness for any signs of damage, corrosion, or loose connections. Pay close attention to areas where the harness might rub against other components. If heat shrink was used for repair, ensure it’s properly sealed.
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Relay Testing: Test the glow plug relay using a multimeter to verify its functionality. You can also try swapping the relay with a known good one to see if the fault code clears.
Conclusion: Resolving Glow Plug Issues
“Check glow plugs vcds” is a valuable diagnostic step for addressing diesel engine starting problems. By understanding the fault codes and utilizing VCDS alongside other diagnostic tools, you can effectively pinpoint the root cause and perform the necessary repairs. Remember to consult your vehicle’s specific repair manual for detailed instructions and specifications. Addressing these issues promptly can prevent further damage and ensure reliable cold weather starts.
