P0C1C

Code

Generic P — Powertrain

Electric/Auxiliary Transmission Fluid Pump Control Module Internal Temperature Sensor Circuit

Brand: Generic

Type: P — Powertrain

Views: UK: 22 EN: 38 RU: 28

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Page language: EN

Causes

Failed internal temperature sensor in the pump control module
Open or shorted sensor wiring (harness chafe, connector damage)
Corroded/loose connector or pins at module/sensor
Water intrusion or contamination of connector or module
Faulty pump control module (internal electronics)
Intermittent fault due to heat, vibration, or intermittent short to battery/ground

Symptoms

MIL/Check Engine or Transmission warning lamp illuminated
Transmission may enter limp-home mode or limit shift strategy
Auxiliary/electric pump may not run or run incorrectly
Erratic shifting, harsh engagement, or reduced transmission cooling
Stored DTC(s) related to temperature sensor or pump control
Possible reduced fuel economy or drivability changes under load

What to check

Read DTC(s) and freeze-frame data with a capable scan tool; note related codes and occurrence conditions
Inspect pump control module connector and wiring for corrosion, damage, pin push-out, or water intrusion
Backprobe connector and monitor sensor signal voltage and reference voltage with key ON, engine OFF
Measure sensor circuit resistance (if serviceable) and compare to specification or expected range
Perform wiggle test on harness while monitoring live data for intermittent changes
Check module power and ground circuits for proper voltage and continuity

Signal parameters

Reference supply: typically a 5 V reference from module/controller (verify exact spec for vehicle)
Typical sensor output range: ~0.5–4.5 V across operating temperature (sensor type dependent); out-of-range or implausible voltages indicate fault
Open-circuit indication: high resistance or infinite Ω between sensor signal and module (often >10 kΩ)
Short indication: very low resistance to ground or battery (often < 5–50 Ω) depending on circuit
Trigger thresholds (generic): signal below ~0.2–0.3 V or above ~4.7–4.9 V, or sudden erratic changes, commonly set fault criteria — verify vehicle-specific thresholds

Diagnostic algorithm

Retrieve all codes and freeze-frame data. Note when fault occurred (engine temp, ambient temp, pump commanded).
Inspect module and harness visually for damage, corrosion, fluid intrusion, rodent chew, or loose connectors.
With connector connected, monitor live data for the transmission pump/module temperature sensor while commanding pump ON/OFF. Observe for sensible temperature changes and stable signal.
With key OFF, disconnect connector and inspect pins for corrosion, bent pins, or water. Repair or clean as needed.
Measure sensor circuit resistance (if externally serviceable) or backprobe signal with key ON; verify 5V reference and good ground at module connector.
Perform continuity checks from sensor signal pin to module and from ground to chassis ground to detect opens/shorts.
Wiggle harness and heat/cool test (if safe) while monitoring live data to reproduce intermittent faults.
If wiring and connector are good but sensor signal remains out of range, test pump control module power/ground and signal processing; substitute known-good module if available or consult OEM procedures.
After repair or component replacement, clear codes, perform functional tests (pump operation and temperature readings), and road test to confirm code does not return.
If fault is intermittent and not reproducible, advise extended road test and monitor with datalogging; consider harness replacement or module replacement per OEM guidance.

Likely causes

Defective internal temperature sensor inside the pump control module
Connector corrosion or poor terminal contact at the pump control module
Open circuit in sensor signal or ground wire (broken wire, pin out)
Short to voltage or ground in sensor circuit
Pump control module internal failure

Fault status

⚠️ Status

Electric/auxiliary transmission fluid pump control module internal temperature sensor circuit fault — sensor signal out of range, open, short, or intermittent.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours