From Ross-Tech Wiki
16502/P0118/000280 - Engine Coolant Temperature Sensor (G62): Signal too High
- Difficulties with starting a cold engine.
- Starting the engine when engine is warmish or warm, idle rpm immediately is 1200 - 3000 rpm.
- RPM at idle is irregular.
- With all engine temperatures idle rpm will often vary between 900 - 1000 rpm.
- With engine warm (90 °C) the engine temperature suddenly drops (70 °C) and slowly comes back to 90 °C.
- Bad acceleration during warm-up.
- Diesel Engines: Glow plug indicator may be on for a longer than normal time or at ambient temperatures where it shouldn't come on at all.
- The electrical signal coming from G62 is too low
- Wiring and/or connections faulty (short circuit?)
- Engine Coolant Temperature Sensor (G62) faulty
- Check wiring and connections
- Check / Replace Engine Coolant Temperature Sensor (G62)
- In many cars between MY 1995-2002 the G2/G62 had a bad reputation for failing often. The original G2/G62 sensor is black and the improved replacements are green.