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Generic P — Powertrain

Motor Electronics Coolant Temperature Sensor C Circuit Range/Performance

Brand: Generic

Type: P — Powertrain

Views: UK: 28 EN: 46 RU: 21

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Read freeze frame and live data for Coolant Temperature Sensor C and related sensors
Compare Sensor C temperature reading to other coolant temp sensors (A/B) or to ambient/expected behavior
Visually inspect sensor C connector and wiring for corrosion, damage, or loose terminals
Backprobe sensor connector to measure signal voltage with key ON / engine OFF and during warm-up
Measure sensor resistance (cold and after warming) and compare to manufacturer spec
Perform wiggle test on harness while observing live data for intermittent changes

Typical sensor circuit is a thermistor producing a voltage between ~0–5 V to the PCM (exact values depend on vehicle); voltage should change smoothly with temperature
At low coolant temperature the sensor resistance is high and measured voltage (with PCM pull-up) is near one end of the range; at high temperature resistance is low and voltage moves toward the opposite end
An open circuit often shows fixed/high voltage or an implausible reading; a short to ground often shows near 0 V
Expected behavior: steady, monotonic change in reported temperature with engine warm-up; no rapid jumps or frozen values

Connect a scan tool and record freeze frame, pending codes and live data for Coolant Temp Sensor C and other temp sensors.
Verify symptoms and note whether the sensor reading is constant, erratic, or out-of-range compared with ambient and actual engine temperature.
With ignition ON (engine OFF) backprobe the sensor connector: confirm reference voltage from the PCM (usually a pull-up) and check for a signal voltage. Compare to expected 0–5 V range for the vehicle.
Start engine and observe sensor voltage/temperature while engine warms. The value should change smoothly; if it is fixed or jumps to extreme values, suspect wiring or sensor.
Remove sensor and measure resistance at known temperatures (cold ambient and warmed sensor). Compare resistances to the vehicle specification or to a known-good sensor chart.
Inspect wiring harness from sensor to PCM for damage, pin corrosion, bent pins, or water intrusion. Repair any damaged wiring or connectors.
If wiring and connector check OK, install a known-good sensor (or swap with another identical sensor if available) and re-check. If code clears and data behaves, replace sensor.
After repairs clear codes and perform a test drive/warm-up cycle to verify the fault does not return. Re-scan for related codes.
If fault persists after sensor and wiring verified, consider PCM input circuit diagnostics or consult manufacturer's technical information for PCM testing or reflash procedures.