P0668

Symptoms

• The Check Engine light comes on
• It is possible to switch to emergency engine operation mode
• Reduced engine power
• Unstable operation of control systems
• Difficulty starting the engine in cold weather

Causes

• Short circuit of the sensor signal wire to ground
• Open or damaged temperature sensor circuit
• ECU internal temperature sensor malfunction
• Oxidation or damage to the ECU connector
• Internal ECU fault

How to Fix

1. Read all error codes with an OBD-II scanner and record the data
2. Visually inspect the wiring and connectors of the ECU for damage, oxidation or breaks
3. Measure the voltage in the temperature sensor circuit A with a multimeter (standard: 0.5–4.5 V)
4. Check the sensor resistance and compare with the manufacturer's technical data
5. Check the circuit for open circuit and short circuit to ground.
6. If the wiring and sensor are in good condition - diagnostics and replacement of the ECU

Related codes

Error P0668 by Vehicle Brand