94 ls400 temp gauge issue..
03-23-14, 02:13 PM
#1
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94 ls400 temp gauge issue..
so while driving my temp gauge never gets past a quater. then it starts to go back down to cold line. i was thinking coolant temp sensor? any other suggestions.(btw if it matters, i have the infamous cluster problem. if thats also a cause of it)
after 30 mins of driving
after 30 mins of driving
03-23-14, 02:50 PM
#7
Lexus Champion
well the first thing to do is to replace that 20 year old, $20 gauge sensor, so that you make sure that what you are seeing on the temp gauge is even accurate - make sure to get the real Toyota part on this one, the part number is 83420-20040 and you can buy it at Sewell Lexus with our Club Lexus discount for $19.50
if your car is truly running colder than it should, this will quickly show up in much worse gas mileage, and as dc893 correctly points out, the thermostat is the most likely culprit!
and again, as critical and inexpensive as this part is, I would go with genuine Toyota (designed and built by Kuzeh) on the thermostat as well. - p/n 90916-A3003 ($15 at Sewell Lexus with discount)
also, the ECU does not get its temperature information from the same sensor as the temp gauge does, on 97 and earlier LS400, there is a separate sensor for the ECU called the Engine Coolant Temperature Sensor p/n 89422-20010 and this sensor can make a huge difference in both performance and mileage. ($49 at Sewell)
both sensors are right beside each other behind the passenger side coil, and easy to install if you can work on cars yourself
if your car is truly running colder than it should, this will quickly show up in much worse gas mileage, and as dc893 correctly points out, the thermostat is the most likely culprit!
and again, as critical and inexpensive as this part is, I would go with genuine Toyota (designed and built by Kuzeh) on the thermostat as well. - p/n 90916-A3003 ($15 at Sewell Lexus with discount)
also, the ECU does not get its temperature information from the same sensor as the temp gauge does, on 97 and earlier LS400, there is a separate sensor for the ECU called the Engine Coolant Temperature Sensor p/n 89422-20010 and this sensor can make a huge difference in both performance and mileage. ($49 at Sewell)
both sensors are right beside each other behind the passenger side coil, and easy to install if you can work on cars yourself
Last edited by LScowboyLS; 03-23-14 at 02:55 PM.
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03-23-14, 02:56 PM
#8
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well the first thing to do is to replace that 20 year old, $20 gauge sensor, so that you make sure that what you are seeing on the temp gauge is even accurate - make sure to get the real Toyota part on this one, the part number is 83420-20040 and you can buy it at Sewell Lexus with our Club Lexus discount for $19.50
if your car is truly running colder than it should, this will quickly show up in much worse gas mileage, and as dc893 correctly points out, the thermostat is the most likely culprit!
and again, as critical and inexpensive as this part is, I would go with genuine Toyota (designed and built by Kuzeh) on the thermostat as well. - p/n 90916-A3003 ($15 at Sewell Lexus with discount)
also, the ECU does not get its temperature information from the same sensor as the temp gauge does, on 97 and earlier LS400, there is a separate sensor for the ECU called the Engine Coolant Temperature Sensor p/n 89422-20010 and this sensor can make a huge difference in both performance and mileage. ($49 at Sewell)
both sensors are right beside each other behind the passenger side coil, and easy to install if you can work on cars yourself
if your car is truly running colder than it should, this will quickly show up in much worse gas mileage, and as dc893 correctly points out, the thermostat is the most likely culprit!
and again, as critical and inexpensive as this part is, I would go with genuine Toyota (designed and built by Kuzeh) on the thermostat as well. - p/n 90916-A3003 ($15 at Sewell Lexus with discount)
also, the ECU does not get its temperature information from the same sensor as the temp gauge does, on 97 and earlier LS400, there is a separate sensor for the ECU called the Engine Coolant Temperature Sensor p/n 89422-20010 and this sensor can make a huge difference in both performance and mileage. ($49 at Sewell)
both sensors are right beside each other behind the passenger side coil, and easy to install if you can work on cars yourself
03-23-14, 03:11 PM
#9
Lexus Champion
03-24-14, 10:44 AM
#10
If that doesn't fix the issue, the problem could be the gauge cluster. It is a fairly common issue that we see. Give us a call if we can help.
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262-456-4147
contact@taninauto.com
www.taninautoelectronix.com
03-24-14, 11:53 AM
#11
Had the same problem on my dad's 93... the only thing that does not work on the gauge is the temp sensor. Replaced the temp sending unit with a new one (not from Lexus... I know)... and that did not fix the problem.
03-24-14, 12:23 PM
#12
There is a simple way to test this. Ground out the single wire connector (temp sensor) on the thermostat housing area with the car on. The gauge in cluster should go to full Hot. If it does not, the cluster is the problem.
If it does, the sensor and or connector or wiring in the connector is bad.
If it does, the sensor and or connector or wiring in the connector is bad.
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