Low engine oil pressure & charging system lights after putting back the air cleaning

Re: Low engine oil pressure & charging system lights after putting back the air clean

Unfortunately you probably can't recover lost text. It's happened to all of us somewhere along the way.

You took it all apart, put it all together, turned the key but did not actually start the van? As JC said, lights on (you've entered a test mode) is normal. Plus, you've done an ECU reset, so don't be surprised if the engine gives you trouble starting, and it may not want to idle. Assuming you have all vacuum hoses and electrical connectors restored, it's unlikely you've caused any real harm, but it may torture you for a while.

Keep you foot on the gas if it stumbles and it should relearn. If the throttle body and plate are dirty, the ECU reset can really thru things off as it learned how to handle the dirt (it changes idle settings) but that learning is now lost. You may have to do a throttle body/plate cleaning to get it to run right.

May I ask WHY you wanted to stare at the tranny? Curiosity really has the better of me here.

Re: Low engine oil pressure & charging system lights after putting back the air clean

jc said:

Jerry,

Did you check the fluid levels for Oil and transmission fluid? When I start my car, the battery and oil light come on at startup and then go away.

Since you disconnected the battery, the computer has been reset and it will need to re-learn. I think you are ok to start the van. The lights should go off after the van starts up. If they don't then shut it off immediately.

Note, if it's really cold, then the oil light might stay lit for more than one or two seconds. Last week when it was -25 C, my oil light was on for about 10 seconds before it went off.

Regards, JC.

Click to expand...

JC,

[Sorry to reply later. had to reset password]

Thanks for your quick reply. This is a great site and you guys are awesome. I have been reading this site for almost a month and learnt quite a lot.

Are you saying that this is normal, i.e., you always see these two lights (engine oil pressure and charging system) on after disconnecting and reconnecting the battery? You mentioned about the temperature. I live in the SF bay area and it is quite warm here already. Did anyone else have the same situation?

The van was working fine before I disconnected the battery. I checked both engine and transmission oil levels a week or so before and they were ok, I think. I do not see anything on the ground now. When I checked the engine oil, the dipstick was smeared around the marks, so it is hard to say for sure. I always had the dealer do the oil. I assume that was ok.

The transmission oil was still pink and clear after 93k miles. The level was easy to see and it was about ¼’ above the high mark. I checked it when it was cold. You said that it was ok to overfill a bit. Others also mentioned that the levels vary even for the brand new vans/cars. I never touched the transmission so it was the original and over filled a bit.

Re: Low engine oil pressure & charging system lights after putting back the air clean

fibber2 said:

Unfortunately you probably can't recover lost text. It's happened to all of us somewhere along the way.

You took it all apart, put it all together, turned the key but did not actually start the van? As JC said, lights on (you've entered a test mode) is normal. Plus, you've done an ECU reset, so don't be surprised if the engine gives you trouble starting, and it may not want to idle. Assuming you have all vacuum hoses and electrical connectors restored, it's unlikely you've caused any real harm, but it may torture you for a while.

Keep you foot on the gas if it stumbles and it should relearn. If the throttle body and plate are dirty, the ECU reset can really thru things off as it learned how to handle the dirt (it changes idle settings) but that learning is now lost. You may have to do a throttle body/plate cleaning to get it to run right.

May I ask WHY you wanted to stare at the tranny? Curiosity really has the better of me here.

Click to expand...

Fibber2,



Thanks for your info. Strange this is so! How come I never read from anywhere. Scared the heck out of me!

No I have not started the van after I saw the lights. I never touched the car before other than driving. Found out recently I did not really know how to drive, e.g., I never used the emergency parking, always used “Drive”…

I wanted to take a look at the transmission is that I got two codes: P0973 and P2714. As you know they both relate to transmission. Someone a while ago asked the same question on this site but nobody replied. It appeared this is a pretty common issue among the Toyota family cars. I wanted to do a little diagnostics before deciding what to do next. Is it the sensor? Wiring? Or the transmission itself? The dealership would charge about $1000 just to do some preliminary diagnostics, e.g., drop the pan stuff. These guys did not even want to tell me what they found out initially, what they did. They just told me to put in another $500 to drop the pan.

As you might know, I have no clues as far as how to tackle the issue but I am learning. It is also a good opportunity for me to learn about the cars. I know many of you are very knowledge but it seemed nobody bothered to put up any info, including many other sites. As I said, this is a pretty common Toyota problem.

Thanks for asking. I will push along and will surely need much help from you SIENNA experts.

Re: Low engine oil pressure & charging system lights after putting back the air clean

Jerry,

Here is what the two codes mean.


P0973 - Shift Solenoid A Control Circuit Low

P2714 Toyota - Pressure Control Solenoid 'D' Performance/Stuck Off

Possible causes- Faulty Shift Solenoid Valve SLT
- Shift Solenoid Valve SLT harness is open or shorted
- Shift Solenoid Valve SLT circuit poor electrical connection


Did you have these issues before you "looked at the transmission"? I'm wondering if the wiring to the tranny has been compromised and you are not getting a good signal.

Some members have had to change the transmission shift soleniods. Sounds like the dealership (aka stealership) will be charging a fortune to diagnose this issue.

Maybe fibber has some information on the tranny wiring to see if you can check that first yourself to see if any wiring is fraying or broken. I would start there first.

Regards, JC.

Re: Low engine oil pressure & charging system lights after putting back the air clean

JC,

[You are a senior member. Do you know how come I always need to reset password?]

Thanks. I had these codes before I took a look at the tranny.

I actually found out a good source for car repair before I almost subscribed to Alldatadiy.com or eautorepair.net. The source is your local library. You cannot find them by search. They hide under the database. The best way would be to ask the librarian.

At this moment I just want to have some knowledge so I know what the dealership is talking about, to find a competent repair shop. The source I mentioned from the library (chilton) had pretty detailed diagnostic procedure.

P0793 seems not a big issue you just need to change the sensor or harness or ECM. If the p2714 is true, that can be a pain. The code explanations you quoted were not Sienna specific.

Also while I was browsing the chilton database, I found out their procedure for checking the ATF. I will see if I can upload here.

Re: Low engine oil pressure & charging system lights after putting back the air clean

A little update [to see if anyone can help, and help others who see the post].

[Still need to reset password before posting!!!]

JC and Fibber2 are dead on right. I was able to start the van despite the warning lights without any problem.

I tested drive the van wanting to duplicate the problem now that I know a little more about the transmission.

I will get p0793 and P2714. On other day it is p0793 and p0776. The troubleshooting procedures for both p02714 and p0776 calls for checking other code first if coexisting, that is p0793, right? P0793 is for the speed sensor. Trouble was the testing by measuring the ohms through the ECM was ok. Calls for 560-680, was around 630. I checked both speed sensors including the one that is good. They both seem ok. Does that mean that the ECM is bad? How can I be sure it is bad? Or how can I be sure the speed sensor is good? Since I have other codes, could these other codes trigger it?

A little on the van behavior. It had been great until recently. After coasting and slowed down, acceleration sometimes was slow as if in neutral. Did not pay attention to the rev. I did feel that the van was not under full control of steering for a short time (a few seconds), kind of like in a free drop in an amusement park, lunging forward on its own.

I tested drive wanting to get more feel on the problem. First I drove slowly it was ok. Then I drove a little faster, one time I can feel the problem from the get-go, not a smooth ride. I am not there yet to tell when the gear shifted actually. A little later, the warning lights were on. Other time it was all right. I drove more and faster [still not too faster <40mph] it was ok. Does this mean the problem was intermittent?

Re: Low engine oil pressure & charging system lights after putting back the air clean

Update.

Even the diagnostics procedures above can be helpful, they are very preliminary, IMO. According to the p0793 procedure, I should assume the sensor (NC) was good because the ohms was within range, and proceed to change the ECM. But the sensor is not a simple resistance . It is a two wired sensor (magnetic based instead of the hall effect one) so it could be bad but still have good resistance.

I happened to measure the resistance of the sensor after the van was off. It turned out its resistance did not quickly return to normal. The other similar senor (NT) did quickly. Therefore, I unplugged the NC sensor and drove a bit. Without the sensor, the van was ok only having the code p0793. It was not a smooth ride but seemed better, no sudden lunges. Now I think the sensor was indeed bad. Any comments, anyone??

I also drove it manually. When it hesitated, it was in L. Shifting to 2 was good, felt right away. From 2 to 3 was delayed noticeably.