Temperature gauge barely working - sensor?
#1
Scooby Regular
Thread Starter
Temperature gauge barely working - sensor?
The temperature gauge on my dash has suddenly started staying near to zero even when the engine is warm. It might occasionally creep off the bottom to about 5%. The engine seems to be running no differently, and I plugged in a OBDII tool to check what temperature that reads, and that says around 70-80 degrees after a bit of a drive, so that seems OK. So is the temperature gauge feed off a different sensor from the one the ECU uses? I'm guessing it's on the pipe that runs across the top of the engine, but where in the pipe is it? I want to eliminate whether its the sensor, gauge, or wiring that's at fault.
The car is a 2005 WRX with a EJ205 standard engine.
The car is a 2005 WRX with a EJ205 standard engine.
#3
Scooby Regular
Item 12 - sits behind the alternator.
Always use the copper washer - Never use ptfe tape on the threads of the sensor as the gauge circuit grounds via the sensor body to earth
Always use the copper washer - Never use ptfe tape on the threads of the sensor as the gauge circuit grounds via the sensor body to earth
#4
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Thread Starter
Thanks for those digrams, very useful.
I just measured the resistance between each of the 3 pins without knowing how they are connected. Didn't think to measure the resistance between pin 3 and the body (ground).
Do you know if the ECU takes the coolant temperature from the same pin 3, or if pins 1 and 2 are used? There's wires going to all 3 wires, so I assume they are all used.
I just measured the resistance between each of the 3 pins without knowing how they are connected. Didn't think to measure the resistance between pin 3 and the body (ground).
Do you know if the ECU takes the coolant temperature from the same pin 3, or if pins 1 and 2 are used? There's wires going to all 3 wires, so I assume they are all used.
#5
Scooby Regular
ECU uses pins 1(common or shield) pin2 (signal)
Relevant Engine Wiring pages
ECU connections
Relevant Engine Wiring pages
ECU connections
#7
Scooby Regular
Thread Starter
The temperature suddenly started working again today! I haven't touched a thing, so maybe a loose connection has sorted itself out? Far too wet out to poke around anyway.
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