P0C1C: Electric/Auxiliary Transmission Fluid Pump Control Module Internal Temperature Sensor Circuit

What it means

The auxiliary transmission fluid pump control module detects a fault in its internal temperature sensor circuit. The code alone does not identify whether the fault is in the sensor, wiring, or module.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

The auxiliary transmission-fluid pump control module uses an internal temperature sensor circuit to monitor its own temperature. P0C1C means the circuit has a fault, but the code alone does not distinguish a sensor failure from an open or shorted connection or a module fault.

Common causes

Most likely first.

1. Faulty internal temperature sensor
2. Open or shorted sensor wiring
3. Poor connector connection
4. Faulty pump control module

Symptoms

• Transmission warning light may illuminate
• Transmission operation may be affected

How to diagnose it

1. Scan for related transmission and pump-module codes, and note live internal-temperature data and freeze-frame conditions before clearing anything.
2. Inspect the auxiliary pump control module connector and accessible wiring for looseness, corrosion, chafing, fluid intrusion, or heat damage.
3. Check the sensor-circuit wiring for opens or shorts using the manufacturer’s circuit test procedure.
4. Compare the reported internal temperature with ambient and other available temperature readings when the module is cold, looking for an implausible signal.
5. If the wiring checks pass, test the internal sensor and pump control module using the manufacturer’s procedure.

Common fixes

• Reconnect or clean a poor module connector where appropriate.
• Repair an open, shorted, or damaged temperature-sensor circuit wire.
• Replace the internal temperature sensor if separately serviceable and confirmed faulty.
• Replace the pump control module if its sensor circuit has failed internally.

Can I keep driving?

If shifts remain normal, drive gently and monitor for transmission warnings; the module may not be able to protect itself using accurate temperature data. Stop driving if shifting becomes harsh, delayed, slipping, or the vehicle enters limp mode.