Where is the temp GAUGE sensor located?
Thread Starter
Cruisin'
Joined: Jun 2009
Posts: 19
Likes: 1
From: puyallup wa
Where is the temp GAUGE sensor located?
Where is the temp GAUGE sensor located on my 2003 TL-S? After I finished replacing the idle air control valve and egr valve (I had to remove throttle body, intake plenum, intake manifold for access + cleaning), temp gauge now goes off-scale high as soon as ignition switch is turned to "run" on a stone-cold engine. I have found a round connector with TWO wires that slides down vertically on a sensor; this is located immediately adjacent to the engine thermostat. This connector was one of many that were disconnected/reconnected, but the wires and connector appear undamaged, click and lock solidly when reconnected, and do not move the gauge at all when wiggled. I did read a thread in this forum stating that the GAUGE sensor was only one wire, but if THAT is true, then where IS the temp gauge sensor?
Burning Brakes
Joined: Dec 2003
Posts: 1,192
Likes: 331
From: Newport beach
https://acurazine.com/forums/second-...manual-988621/
check out page 248 (10-6) in the service manual.
10-8 gives info on troubleshooting.
check out page 248 (10-6) in the service manual.
10-8 gives info on troubleshooting.
Thread Starter
Cruisin'
Joined: Jun 2009
Posts: 19
Likes: 1
From: puyallup wa
Found ECT sensor, thank you White Tiger.
I guess the shop manual I'm using is different from yours, as page 248 doesn't pertain to ECT sensors or gauges, but rather " Multiplex Control Unit, Door".
Anyway, page 2126 of 22608 "Coolant Temperature Gauge Test" is the most relevant test I could find. I was stopped cold when it told me to
"4. Turn the ignition switch ON (II), and measure voltage between PCM connector terminal A31 and body ground." I cannot access the Powertrain Control Module" (PCM) or PCM connector A 31 because it is located under the console, and I was unable to pull the carpeting away on either driver or passenger side. However, it also says wire A 31 is green w/yellow stripe though! Moreover, the symptoms don't appear to align with the logic in this test.
-With the IGN SW in "off", the temp gauge reads bottom of scale. Turn it to position II, and the gauge goes off scale high, even if the car is 24 hours cold. Pull the connector from the sensor in position II, the gauge returns to bottom of scale, regardless of coolant temp.
-Checked resistance of the ECT sensor (not it's connector) between the two pins with engine cold, 81 ohms. Start engine and warm it up; resistance gradually drops as coolant warms, hitting 52 ohms, then slowly swinging between 52 and 56 ohms as the cooling system thermostat modulates. I believe this means the sensor checks good.
-Since I could not access the PCM, I checked the voltage from ground to the green and yellow wire at the disconnected sensor connector; zero volts w/IGN in position II. Checking from ground to the red wire read 5 volts w/IGN in position II. At this point, I thought grn+yel wire was broken, so I turned off IGN and checked resistance from ground to the grn+yel; got 1 ohm (shorted to ground). So much for a broken wire! I rechecked that resistance with the IGN in POS II, and got 1500 (1.5 kOhms). Is the PCM supposed to ground out the grn+yel wire when the IGN sw is off?
Each and every time I turn the IGN sw to position II, the VSA light comes on, followed two seconds later by the check engine light and yellow warning triangle. The only code code is P1519, which will not clear. Being that I just finished replacing the idle air control valve, this is very frustrating. But, it still makes sense because;
-the idle air control valve position is determined by the coolant temperature, which is totally whacked (read top of post)
-engine starts fine when warm, but is extremely hard to start when cold (exactly like trying to start a carburated engine WITHOUT A CHOKE in cold weather)
-A/C compressor clutch will not energize when air conditioning or defrost is turned on (both radiator fans instantly kick in, though)
-with no A/C or defrost selected, radiator fan never turns on.
Next, I will verify that I did install a throttle body gasket when reinstalling the intake plenum and manifold, and then meterize the connectors at the new idle air control valve. I would be astonished if Rock Auto sold me a bum IACV, as they have a great reputation!
I welcome any and all questions and comments; Acurazine has been most helpful.
Anyway, page 2126 of 22608 "Coolant Temperature Gauge Test" is the most relevant test I could find. I was stopped cold when it told me to
"4. Turn the ignition switch ON (II), and measure voltage between PCM connector terminal A31 and body ground." I cannot access the Powertrain Control Module" (PCM) or PCM connector A 31 because it is located under the console, and I was unable to pull the carpeting away on either driver or passenger side. However, it also says wire A 31 is green w/yellow stripe though! Moreover, the symptoms don't appear to align with the logic in this test.
-With the IGN SW in "off", the temp gauge reads bottom of scale. Turn it to position II, and the gauge goes off scale high, even if the car is 24 hours cold. Pull the connector from the sensor in position II, the gauge returns to bottom of scale, regardless of coolant temp.
-Checked resistance of the ECT sensor (not it's connector) between the two pins with engine cold, 81 ohms. Start engine and warm it up; resistance gradually drops as coolant warms, hitting 52 ohms, then slowly swinging between 52 and 56 ohms as the cooling system thermostat modulates. I believe this means the sensor checks good.
-Since I could not access the PCM, I checked the voltage from ground to the green and yellow wire at the disconnected sensor connector; zero volts w/IGN in position II. Checking from ground to the red wire read 5 volts w/IGN in position II. At this point, I thought grn+yel wire was broken, so I turned off IGN and checked resistance from ground to the grn+yel; got 1 ohm (shorted to ground). So much for a broken wire! I rechecked that resistance with the IGN in POS II, and got 1500 (1.5 kOhms). Is the PCM supposed to ground out the grn+yel wire when the IGN sw is off?
Each and every time I turn the IGN sw to position II, the VSA light comes on, followed two seconds later by the check engine light and yellow warning triangle. The only code code is P1519, which will not clear. Being that I just finished replacing the idle air control valve, this is very frustrating. But, it still makes sense because;
-the idle air control valve position is determined by the coolant temperature, which is totally whacked (read top of post)
-engine starts fine when warm, but is extremely hard to start when cold (exactly like trying to start a carburated engine WITHOUT A CHOKE in cold weather)
-A/C compressor clutch will not energize when air conditioning or defrost is turned on (both radiator fans instantly kick in, though)
-with no A/C or defrost selected, radiator fan never turns on.
Next, I will verify that I did install a throttle body gasket when reinstalling the intake plenum and manifold, and then meterize the connectors at the new idle air control valve. I would be astonished if Rock Auto sold me a bum IACV, as they have a great reputation!
I welcome any and all questions and comments; Acurazine has been most helpful.
Burning Brakes
Joined: Dec 2003
Posts: 1,192
Likes: 331
From: Newport beach
It is possible to receive a defective electronic part; especially if it is not oem. your CEL points to a malfunction in that part.
Do you still have the old IACV? Perhaps plug that in (do not install it), reset the PCM and turn the ignition to ON II (do not start the car) to see if the CEL registers once more.
If not; then plug the old back in; and confirm once more.
Do you still have the old IACV? Perhaps plug that in (do not install it), reset the PCM and turn the ignition to ON II (do not start the car) to see if the CEL registers once more.
If not; then plug the old back in; and confirm once more.
Thread Starter
Cruisin'
Joined: Jun 2009
Posts: 19
Likes: 1
From: puyallup wa
It is possible to receive a defective electronic part; especially if it is not oem. your CEL points to a malfunction in that part.
Do you still have the old IACV? Perhaps plug that in (do not install it), reset the PCM and turn the ignition to ON II (do not start the car) to see if the CEL registers once more.
If not; then plug the old back in; and confirm once more.
Do you still have the old IACV? Perhaps plug that in (do not install it), reset the PCM and turn the ignition to ON II (do not start the car) to see if the CEL registers once more.
If not; then plug the old back in; and confirm once more.
CEL did register. So I called Beck/Arnley, they said to measure resistance between the three pins on the new IACV, being mindful that there is a diode in the circuit path, so reverse leads (polarity) from DVOM and test a second time. I did, and the circuit was open (infinite ohms) regardless of polarity, regardless of pins; the new IACV was DOA! BUT, RockAuto was helpful and kind on agreeing to a refund. I have ordered another IACV as well as a new ECT sending unit (sensor). If these don't fix the problem, I am going to ask Acurazine for help on accessing my PCM under the center console. The shop manual directs me to "pull the carpeting" from both driver and passenger sides of the center console; it is clearly NOT that simple!
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