Solar Sensors - A/C
02-24-14, 02:38 AM
#1
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Solar Sensors - A/C
Anyone have a suggestion regarding engine RPM drops to 500 RPM when A/C is switched on. The Rpm fluctuates between 500 -900 making city driving awkward. I did a scan and came uo with two codes B1421 & B 1424 indicating solar sensors. A/C is working ok. Am I on the right track?? Is it possible both sensors went out the same time. Any suggestions would be greatly appreciated.
LCAN:::confused
LCAN:::confused
02-24-14, 07:42 AM
#2
Moderator
Anyone have a suggestion regarding engine RPM drops to 500 RPM when A/C is switched on. The Rpm fluctuates between 500 -900 making city driving awkward. I did a scan and came uo with two codes B1421 & B 1424 indicating solar sensors. A/C is working ok. Am I on the right track?? Is it possible both sensors went out the same time. Any suggestions would be greatly appreciated.
LCAN:::confused
LCAN:::confused
Those two solar sensors are used to compensate the target temperature. One is located at the passenger side for a JDM Celsior as is shown below and the other at the driver side.
It is strange that two sensors fail at the same time. But the code 21and 24 mean so. You can check and compare them measuring the resistance when the sun is shinning and when not or just hide the sensor by your hand. If the resistance changes enough (K Ohm order change), sensors are OK, probably the A/C controller, the wiring or connection might have some problem.
03-03-14, 09:50 PM
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Solar sensors a/c
THANKS YAMAE & LEGHOST
I did as you suggested and the sensors checked out ok. I cleaned the throttle plate as was suggested in other threads, I did not remove any parts of the throttle body but just sprayed carb cleaner in the location and wipped it with a clean cloth. I did notice that the throttle plate was not fully closed with the ignition off, but it appeared to close with the ignition switched on. The result after cleaning was the fluctions problem was resolved, however the RPM is now steady @ 2000 Rpm at @ idle. Re-scanning I no longer have the solar codes; don't know why ??? I suspected a vacuum leak however so far cannot find one. There is a small plate just above the throttle plate with two phillips screws retaining it; when I removed it there was an excessive amount of carbon inside the port. and with the plate removed the RPM dropped to 1500 RPM. I cleaned out the carbon and installed the plate , however the RPM is still at 2000. I suspect this may be the source of the problem but not sure what process to perform next. How far into the throttle body shouild I venture or is there some other items I should be looking into? I don't have the option of just going to a parts shop to buy parts for this vehicle in tthis region. I would have to order parts from overseas which takes some time 45-60 days plus excessive shipping cost, so I don't want to go the route of trying new parts until I fine the solution; I need to discover the actual source of the problem and replace the required part / parts. Your advise would be greatly appreciated.
Thanking in advance for your advice.
LCAN
I did as you suggested and the sensors checked out ok. I cleaned the throttle plate as was suggested in other threads, I did not remove any parts of the throttle body but just sprayed carb cleaner in the location and wipped it with a clean cloth. I did notice that the throttle plate was not fully closed with the ignition off, but it appeared to close with the ignition switched on. The result after cleaning was the fluctions problem was resolved, however the RPM is now steady @ 2000 Rpm at @ idle. Re-scanning I no longer have the solar codes; don't know why ??? I suspected a vacuum leak however so far cannot find one. There is a small plate just above the throttle plate with two phillips screws retaining it; when I removed it there was an excessive amount of carbon inside the port. and with the plate removed the RPM dropped to 1500 RPM. I cleaned out the carbon and installed the plate , however the RPM is still at 2000. I suspect this may be the source of the problem but not sure what process to perform next. How far into the throttle body shouild I venture or is there some other items I should be looking into? I don't have the option of just going to a parts shop to buy parts for this vehicle in tthis region. I would have to order parts from overseas which takes some time 45-60 days plus excessive shipping cost, so I don't want to go the route of trying new parts until I fine the solution; I need to discover the actual source of the problem and replace the required part / parts. Your advise would be greatly appreciated.
Thanking in advance for your advice.
LCAN
03-03-14, 09:56 PM
#4
Lexus Champion
03-03-14, 09:57 PM
#5
Lexus Champion
you have to clean those little magic mystery holes in the throttle body!
also, please replace your engine coolant temp sensor with the correct one from the dealership - Toyota p/n 89422-30030 - ($49 at Sewell Lexus with our discount)
one of these two is very likely the issue!
also, please replace your engine coolant temp sensor with the correct one from the dealership - Toyota p/n 89422-30030 - ($49 at Sewell Lexus with our discount)
one of these two is very likely the issue!
Last edited by LScowboyLS; 03-03-14 at 10:02 PM.
03-04-14, 05:31 PM
#6
Moderator
>The result after cleaning was the fluctions problem was resolved, however the RPM is now steady @ 2000 Rpm at @ idle.
I doubt that the engine coolant temp sensor causes that high rpm. There is a simple way to check it. Use a resistor about 100 ohm (47-150 ohm would be OK) instead of the engine coolant temp sensor. If the problem is still there, the engine coolant temp sensor is not the cause. With a 100 ohm resistor, the engine will rev around 900rpm or little less. All you need to perform this is to remove the connector and attach a 100 ohm resistor to the removed connector terminals.
>Re-scanning I no longer have the solar codes; don't know why ???
The result is affected how bright the place where you check is. The code always appears when you check not at under the sunshine.
>I suspected a vacuum leak however so far cannot find one.
You need to check leaks intensively. I suggest you to check the lower side of PCV hose where you can't see without removing it.
>There is a small plate just above the throttle plate with two phillips screws retaining it; when I removed it there was an excessive amount of carbon inside the port.
This is the air mix path to injectors for the better gas mileage. The photo bellow is so. The air is sent via 8 smaller holes at the bottom and 2 larger holes at the side. What you have seen are those. Accumulated carbon deposits tend to block the passage and you would have lower engine rpm and a bad gas mileage. Cleaning this area increases the rpm but only about a few hundred rpm. 2000rpm is too much.
Anyway, there must be some other reason why you have 2000rpm. One of those may be the throttle position sensor. A failed or poorly adjusted one sometimes causes unusual idle rpm. It should be adjusted to set at 15.2±0.8% at the idle but you need a Toyota genuine diagnostic equipment called S2000 to do this.
The properly adjusted throttle position sensor and the clean throttle body should provide you 750rpm ± 50rpm after the ECU leaned things and fully warmed up.
If the tool S2000 is not available at all, one idea is to try and error rotating the throttle position sensor little by little but be careful not to mess things totally up. And also mark the original position before you try aiming to realign to the original position when not successful.
I doubt that the engine coolant temp sensor causes that high rpm. There is a simple way to check it. Use a resistor about 100 ohm (47-150 ohm would be OK) instead of the engine coolant temp sensor. If the problem is still there, the engine coolant temp sensor is not the cause. With a 100 ohm resistor, the engine will rev around 900rpm or little less. All you need to perform this is to remove the connector and attach a 100 ohm resistor to the removed connector terminals.
>Re-scanning I no longer have the solar codes; don't know why ???
The result is affected how bright the place where you check is. The code always appears when you check not at under the sunshine.
>I suspected a vacuum leak however so far cannot find one.
You need to check leaks intensively. I suggest you to check the lower side of PCV hose where you can't see without removing it.
>There is a small plate just above the throttle plate with two phillips screws retaining it; when I removed it there was an excessive amount of carbon inside the port.
This is the air mix path to injectors for the better gas mileage. The photo bellow is so. The air is sent via 8 smaller holes at the bottom and 2 larger holes at the side. What you have seen are those. Accumulated carbon deposits tend to block the passage and you would have lower engine rpm and a bad gas mileage. Cleaning this area increases the rpm but only about a few hundred rpm. 2000rpm is too much.
Anyway, there must be some other reason why you have 2000rpm. One of those may be the throttle position sensor. A failed or poorly adjusted one sometimes causes unusual idle rpm. It should be adjusted to set at 15.2±0.8% at the idle but you need a Toyota genuine diagnostic equipment called S2000 to do this.
The properly adjusted throttle position sensor and the clean throttle body should provide you 750rpm ± 50rpm after the ECU leaned things and fully warmed up.
If the tool S2000 is not available at all, one idea is to try and error rotating the throttle position sensor little by little but be careful not to mess things totally up. And also mark the original position before you try aiming to realign to the original position when not successful.
Last edited by Yamae; 03-05-14 at 12:02 AM.
03-04-14, 11:58 PM
#7
Moderator
The drawing below may help you some more.
