detroit 442

Fans are running as soon as ignition is switched on and even when engine is cold. Also the check engine light is staying on. Any ideas as to the cause of this problem and will i be able to repair it myself.

DaveD

iTrader: (2)

If you do the old black connectors thing, you'll probably find fault code 21 - Water Temp sensor.

Basically your ECU can't determine the engine/coolant temp, and it puts the fans on as a precaution (only at low speeds mind). You'll probably have a poor idle until the engine does warm up?

I have an intermittent problem on my WRX, but haven't changed the sensor yet 'cause it's in one of those typically hard-to-get-to places on top of the engine block! The sensor is around 30 quid from your friendly Subaru dealer, but I've no idea how much they would want to charge you for fitting.....

RICH WILD

It's fairly easy to fit yourself. Takes about 1/2 hour.

It's under the inlets, near the turbo on early cars. Will have to take a few pipes off (and intrecooler probably to get access. Just undo the connector and unscrew it and fit the new one. It will p1ss water out for a few seconds while you do the swap over, so be quick. Then top your coolant level back up.

Any mechanic should be able to do it for you.

Cheers

Rich

Hobbsy

Or the fuse that controls the cigar lighter. I had this below when a mobile phone charger blew up, the result was the fuse blown for that circuit and also constant fans. Check that B4 laying out for a new sensor.