Before You Replace That ECU: A Common Fix for Fault Code 16502
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Before You Replace That ECU: A Common Fix for Fault Code 16502
The Issue at Hand
If you're dealing with fault code 16502/P0118/000280 - Engine Coolant Temperature Sensor (G62): Signal too High on your ECU (part number 06K907425E), don't rush to replace the ECU just yet. This code commonly appears on various 1.4 TFSI engine variants, including both the CYFB (with cylinder deactivation/ACT) and CNTC versions.
What We've Learned from Experience
After testing numerous ECUs with this exact fault code, we've discovered a pattern that could save you time and money: the problem is often not the ECU itself, but rather a broken or faulty wiring connector.
Check This First
Before condemning your ECU or even replacing the coolant temperature sensor:
- Inspect the wiring connector to the coolant temperature sensor (G62)
- Look for signs of:
- Physical breaks or cracks in the connector housing
- Corroded or damaged pins
- Loose or backed-out terminals
- Signs of water ingress or contamination
Why This Happens
The wiring connector is exposed to harsh engine bay conditions including heat cycles, vibration, and potential coolant leaks. Over time, these factors can cause the connector to deteriorate, creating intermittent or permanent connection issues that trigger the "signal too high" fault code.
The Bottom Line
We've received many ECUs for testing with this fault code, only to find the ECU was functioning perfectly. The real culprit? A faulty connector that could have been replaced for a fraction of the cost.
Save yourself the expense and downtime - always check the wiring and connectors first when diagnosing fault code 16502. A simple connector repair or replacement might be all you need to get back on the road.
Remember: Proper diagnosis starts with the basics. Check connections before replacing components.
