2000 f150 4.6l the temp sensor is reading low, below the usual normal reading. Woundering what the problem might be. Possible theromstat bad? 73,000miles on truck

 

Does the heat still work properly and have you noticed a loss of power or fuel economy?

 

heat works properly. no loss of power.

 

Well it's prob. just the temp sensor, it uses two ECT's, one for the PCM and one for the idiot gauge, if everything is ok, then the one for the gauge is prob. just bad.

 

Check the connections on the sensors, remove and reconnect ensuring you hear the click of the lock engaging.

 

2000 4.6 has only a CHT (CYLINDER HEAD TEMPERATURE) sensor. No coolant sensor. The CHT sends a signal to the PCM and the PCM sends a signal to the instrument cluster. Does the engine get up to operating temperature? Is the rad warm, hot or cold? The CHT is located on the driver side cylinder head in the valley at the front. Not an easy sensor to get to.

Regards

Jean Marc Chartier

 

Well thats funny, the Ford Service Manual on PTS I'm looking at definetly shows a ECT, and a CHT, and the ECT goes to the I/C.

 

I'll look into it more on the weekend and let you know the outcome.

 

I replaced the thermostat. and the temp gage is back to normal.

 

Just pull it out and clean the bottom of it - they'll develop a film or coating over time on the bottom. Clean. - Prolly only take you 15 minutes to do and it should be more accurate - Well, as accurate as they can be anyway

 

2000 model year still used a CHT and an ECT, the ECT is located near the t-stat on the crossover I believe. 2001 and later went to the CHT only setup......

 

My 2000 MY, 1999 build, did not have any CTS. I used the harness from my 4.6 to run this 5.4 and there was no CTS........

Regards

Jean Marc Chartier

 

You may be right, but the funny thing about that year (2000) is that some 4.6L's had COP ignitions and some had coil packs.. I'm not totally sure, but I'm thinking the ECT was deleted on the COP upgraded models - mid year.

 

My 00 was built in 99 and it had COP ignition.

Regards

Jean Marc Chartier

 

Dude not doubting you...maybe the build date comes to play..I just looked up in the PC/ED's for 1999-2004 and the last year it listed one was 2000...My PC/ED is the one hooked up to Ford's servers so I'd be willing to bet it is pretty accurate............... cheers!