GMC Yukon Water Sensor Causing Multiple Engine Issues

I dealt with a similar car sensor issue on my 2003 GMC Sierra. Having some experience with auto electronics, I initially thought it was going to be much more complex. After running car diagnostics, the problem showed similar symptoms, rough engine and warning lights. My mechanic performed thorough sensor testing which revealed it was actually just a damaged cable connection to the water temp sensor, not the sensor itself. The repair involved cleaning the connector and replacing a section of wiring that had corroded. Total cost was 95 Euro for parts and labor. The sensor issue was resolved completely after fixing the connection. The most important lesson learned was not to immediately assume the sensor needs replacement. Often these sensor-related problems stem from wiring or connector issues. To provide more specific advice for your case, could you share: Have you retrieved the specific error codes? Does the rough running occur more when the engine is cold or warm? Are there any coolant temperature fluctuations showing on the dash? Have you noticed any coolant leaks? This information would help determine if your problem matches what I experienced with my Sierra.

Thanks for the feedback. My service record shows 119611 KM and I just got another malfunction indicator on the dash this morning. The error codes I got were P0116 and P0117, which point to electrical fault issues with the sensor circuit. The engine runs especially rough when cold, taking longer than usual to warm up. No obvious coolant leaks so far, but the temperature gauge has been acting erratic, jumping between normal and cold readings. After hearing about your wiring experience, I will have the connections checked first before replacing any parts. The auto electronics diagnosis makes sense since these symptoms started gradually rather than suddenly. Would still appreciate input from others who might have tackled similar sensor testing scenarios with this specific engine setup.

Thanks for providing those specific error codes, P0116 and P0117 are exactly what I encountered with my Sierra before finding the wiring issue. The erratic temperature readings you describe match my experience perfectly. The gradual onset of your moisture sensor problems strongly suggests a deteriorating connection rather than sudden sensor failure. On my Sierra, the connector pins had developed corrosion over time, causing inconsistent readings especially during cold starts. A few key points from my repair experience: The connector housing had trapped moisture, accelerating corrosion, The repair involved cleaning contacts and applying dielectric grease, Total repair time was under 2 hours, No sensor replacement was needed The rough running during cold starts is particularly telling. My engine showed identical symptoms until the wiring was fixed. Once repaired, the engine temperature sensor began reading correctly and cold start performance returned to normal. Consider requesting a detailed inspection of the entire sensor circuit, including: Connector integrity, Wire insulation condition, Ground connection quality, Pin corrosion checks The car diagnostics may also reveal if there are any related coolant temperature sensor issues affecting the readings.

The water sensor symptoms you described match my situation exactly. After checking my error codes again today, I can confirm both P0116 and P0117 are still present. The malfunction indicator keeps lighting up during cold starts. Your wiring repair experience is particularly relevant, my engine also runs rough when cold and the temperature readings are inconsistent. The electrical fault seems the most likely culprit given how the problem developed gradually. I have scheduled an appointment at my local shop to have the auto electronics thoroughly checked, specifically requesting inspection of: All sensor connections, Wiring harness condition, Electrical ground points, Connector corrosion Will ask them to test the complete sensor circuit before replacing any parts. The diagnostic steps you outlined make sense, especially checking for trapped moisture that could cause connection issues. Thanks for sharing your experience, it has helped narrow down the potential causes. Will update the forum once I get the results from the detailed car sensor inspection and what the actual repair involves.